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England and Wales Court of Appeal (Civil Division) Decisions
You are here: BAILII >> Databases >> England and Wales Court of Appeal (Civil Division) Decisions >> Schlumberger Holdings Ltd v Electromagnetic Geoservices AS  EWCA Civ 819 (28 July 2010)
Cite as:  EWCA Civ 819,  RPC 33
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COURT OF APPEAL (CIVIL DIVISION)
ON APPEAL FROM THE HIGH COURT OF JUSTICE
CHANCERY DIVISION (PATENTS COURT)
The Hon Mr Justice Mann
HC 07 CO1084/HC 07 CO1487/HC 07 CO 1488
Strand, London, WC2A 2LL
B e f o r e :
THE RT HON LORD JUSTICE JACOB
THE RT HON LORD JUSTICE SULLIVAN
| Schlumberger Holdings Limited
(a company incorporated in the British Virgin Islands)
|- and -
|Electromagnetic Geoservices AS
(a company incorporated in Norway)
Michael Silverleaf QC and Hugo Cuddigan (instructed by Freshfields Bruckhaus Deringer LLP) for the Respondent/Claimant
Hearing dates: 26-30 April 2010
Crown Copyright ©
Lord Justice Jacob:
The problem addressed by the Patent
 Although there have been significant improvements in modern times (including the introduction of 3D seismics in the 1980s), seismics do not provide a complete solution in the search for oil. They do not always give the detail and characterisation of sub-strata that an oil company would wish to have. It is sometimes useful to have a different "view" of what is down there. The more information that is available, the better. Under some conditions seismics cannot see everything that needs to be seen.
The Patented Solution
 It has been appreciated by the present applicants that while the seismic properties of oil-filled strata and water-filled strata do not differ significantly, their electromagnetic resistivities (permittivities) do differ. Thus, by using an electromagnetic surveying method, these differences can be exploited and the success rate in predicting the nature of a reservoir can be increased significantly. This represents potentially an enormous cost saving.
(It was common ground that the reference to "permittivities" could be ignored).
1. A method of performing a survey of subterranean strata in order to search for a hydrocarbon containing submarine reservoir (35), or to determining the nature of a submarine reservoir (35) whose approximate geometry and location are known, which comprises: applying a time varying electromagnetic field to the subterranean strata; detecting the electromagnetic wave field response; seeking, in the wave field response, a component representing a refracted wave (43,43C); and determining the presence and/or nature of any reservoir (35) identified based on the presence or absence of a refracted wave component (43,43C); in which the transmitted field is in the form of a wave, and in which the distance between the transmitter (37) and a receiver (38) is given by the formula
0.5 λ ≤ l ≤ 10 λ;
where λ is the wavelength of the transmission through the overburden (34) and l ?the distance between the transmitter (37) and the receiver (38).
1A. A method of performing a survey of subterranean strata in order to determine whether a submarine reservoir (35), whose approximate geometry and location are known, contains hydrocarbons or water, which method comprises: applying a time varying electromagnetic field to the subterranean strata; detecting the electromagnetic wave field response; seeking, in the wave field response, a component representing a refracted wave (43,43C); and determining whether the reservoir (35) contains hydrocarbons or water based on the presence or absence of a refracted wave component (43,43C); in which the transmitted field is in the form of a wave, and in which the distance between the transmitter (37) and a receiver (38) is given by the formula
0.5 λ ≤ l ≤ 10 λ;
where λ is the wavelength of the transmission through the overburden (34) and l is the distance between the transmitter (37) and the receiver (38).
"Overburden" means the rock between the sea bottom and the subterranean strata the subject of interest (whose position and depth have been determined by seismic methods) "l" (the transmitter/receiver distance) is also called the "offset."
 The present invention arises from an appreciation of the fact that when an EM field is applied to subterranean strata which include a reservoir, in addition to a direct wave component and a reflected wave component from the reservoir, the detected wave field will include a 'refracted' wave component from the reservoir. The reservoir containing hydrocarbon is acting in some way as a wave guide. For the purposes of this specification, however, the wave will be referred to as a 'refracted wave', regardless of the particular mechanism which in fact pertains.
 Be that as it may, a refracted wave behaves differently, depending on the nature of the stratum in which it is propagated. In particular, the propagation losses in hydrocarbon stratum are much lower than in a water-bearing stratum while the speed of propagation is much higher. Thus, when an oil-bearing reservoir is present, and an EM field is applied, a strong and rapidly propagated refracted wave can be detected. This may therefore indicate the presence of the reservoir or its nature if its presence is already known. Preferably, therefore, the method according to the invention further includes the step of analyzing the effects on any detected refracted wave component that have been caused by the reservoir in order to determine further the content of the reservoir based on the analysis.
 This is best explained by reference to [fig. 2 of the patent reproduced here:]
37 and 38 are the transmitter and receiver respectively. 41 represents the "direct wave", which can be considered to be the wave which passes directly through the water. Since seawater is relatively conductive (relatively less resistive) the signal or wave attenuates faster than waves passing through more resistive structures. 34 is the seabed (the top of the overburden). 35 is the target layer, supposed for these purposes to be more resistive if it contains oil than it would be if it contained water. 42a and 42b represent a supposed reflected wave, being reflected off the top of the questioned layer. 43 is the "refracted wave". It represents a wave which is said to pass into the layer, and then to be refracted so that it can be picked up via the sort of route shown. This is the key to the invention. It depends on being able to "seek" this wave and identify it. If the layer contains water and not oil, the wave will not be present, or at least not in the same way, and the overall measured signals picked up will be different. As will appear from paragraph 0012 of the patent, it is said that the direct wave and the reflected wave, both of which will have passed through media which will have a lower resistivity than the questioned (oil-bearing) layer, will have attenuated more than the refracted wave, so that detection is facilitated; and it is said it (the refracted wave) will travel faster and with less attenuation in the more highly resistive layer, and so be detected first and more strongly. In the words of the patent:
 The transmitted wave also results in a refracted wave 43. This is composed of a downward portion 43a which descends through the overburden 34, a refracted portion 43b which travels along the layer 35, and an upward portion 43c which travels back up through the overburden 34. Since the refracted portion 43b travels much faster through the oil-bearing layer 35 and with far less attenuation, the refracted wave 43 is detected first by the detector 38 and at a relatively high signal level, compared to the direct wave 41 and the reflected wave 42a, 42b.
The attacks on Validity
Obviousness over Chave
Obviousness over MacGregor
Novelty and obviousness over Srnka
Novelty over Yuan
The names of the citations are those used by the parties and Judge for the purposes of this case.
The Person skilled in the Art
(a) How the question arises
Accordingly, looking at what actually happened in practice, those with a practical interest in this invention would not have included a CSEM specialist, especially where a marine survey was involved.
There were only two sources (sets of equipment) in the world capable of carrying out marine CSEM of the sort needed, and they were in the hands of academics in Cambridge/Southampton, and at the Scripps Institute in San Diego.
If you approach him [i.e. a CSEM expert] and say, "Can I use it for these purposes?" we are not suggesting that, in those circumstances, when the CSEM sat down and thought about it, he would say, "Sorry, it is not going to work." He would say, "It has a good enough chance of working to give it a run although we have never thought of doing this before.
(b) Same for all purposes?
If the art is one having a highly developed technology, the notional skilled reader to whom the document is addressed [i.e. the cited piece of prior art] may not be a single person but a team, whose combined skills would normally be employed in that art in interpreting and carrying into effect instructions such as those which are contained in the document to be construed.
7.1.2 Competent skilled person – group of people as "skilled person"
Sometimes the "skilled person" may be a group of people, such as a research or production team. For the purposes of Art. 56 EPC the person skilled in the art is normally not assumed to be aware of patent or technical literature in a remote technical field. In appropriate circumstances, however, the knowledge of a team consisting of persons having different areas of expertise can be taken into account (T 141/87, T 99/89). This would be the case in particular if an expert in one particular field was appropriate for solving one part of the problem, while for another part one would need to look to another expert in a different area (T 986/96).
Thus, the board stated, for example, in T 424/90 that in real life the semiconductor expert would consult a plasma specialist if his problem concerned providing a technical improvement to an ion-generating plasma apparatus. In T 99/89 too, the board took the view that "competent skilled person" could be taken to mean a team of two or possibly more experts from the relevant branches.
In T 164/92 (OJ 1995, 305) it was observed that sometimes the average skilled person in electronics, particularly if he did not have an adequate knowledge of programming languages himself, might be expected to consult a computer programmer if a publication contained sufficient indications that further details of the facts described therein were to be found in a program listing attached as an annex thereto.
 The starting point in this area of debate should be the classic formulation in Catnic Components v Hill & Smith  RPC 183. At p 242 Lord Diplock said:
"My Lords, a patent specification is a unilateral statement by the patentee, in words of his own choosing, addressed to those likely to have a practical interest in the subject matter of his invention (i.e. 'skilled in the art'), by which he informs them what he claims to be the essential features of the new product or process for which the letters patent grant him a monopoly … The question in each case is: whether persons with practical knowledge and experience of the kind of work in which the invention was intended to be used, would understand that strict compliance with a particular descriptive word [etc]". (My emphasis)
I do not agree that this well-known passage is relevant at all to the point now in issue. Lord Diplock was concerned with something quite different – how the court is to determine the scope of patent claims. The notional skilled reader (which may be a team) is assumed to have the patent in hand, to have read it with his common general knowledge and to interpret the claims on that basis. (Actually the modern (post-EPC) formulation of the rules about that are to be found in Kirin-Amgen  UKHL 46 with some refinements in later cases.) Lord Diplock was not even considering a notional team at all – which is hardly surprising given the simplicity of the mechanical invention in that case.
….. I must draw a distinction between section 3 [= Art. 56] and section 14(3)[= Art. 83]. Each of these refers to the person skilled in the art, and it has been assumed that since the words are the same the person and his attributes must also be the same, whichever section is in play. In the case of the classical mechanical engineering patent, this is true. Whether one is asking if the addressee can read the drawings and the description, so as to be able to work the invention, or if the skilled man can proceed from the drawings and descriptions of the prior art to the new product or process without inventiveness, there is no difficulty in using the same notional skilled artificer as the touchstone. But the position here is different. Once given that we are concerned with a series of different arts practised in this complex field, it cannot be assumed that the arts in which the hypothetical persons are skilled will be the same whether they are addressees who start with the patent and try to make it work, or persons who start with the prior art and try to get to the patent. This is indeed obvious in the present case, since the amino acid sequencer who is a vital member of the discovering team will be redundant when the addressees are seeking to fabricate (say) the claimed expression vectors, since ex hypothesi they will know, not just the five or six bases which were derived en route to the discovery but the full length of the protein sequences.
I agree ... that the question in this case really is: Would it have been obvious to a man, who I can perhaps describe as the drawing-board man, to go to a bearing man with a view to seeing if he could get assistance on the question of reduction of frictional effect? There have of course been a number of cases where it has been rightly pointed out that it is no good just considering what might or might not have been obvious to the workman in the particular field with which the patent is concerned (in this case the drawing-board man) because very often the man working in a relatively limited field will realise that he must seek outside assistance to enable him to solve particular problems with which he may be faced, and I was referred to a number of well known authorities in which it is pointed out that nowadays in particular you do not want to consider what might be obvious to one particular individual working in one particular field because very often it is quite inevitable that a team of individuals is going to be involved and if it would be obvious to the team then that is good enough. But so far as I am aware this is not a case in which those who use apparatus of this kind were struggling desperately to get over some problems which really completely inhibited their activities; it is not a case where manufacturers of apparatus of this kind were really failing to put the apparatus on the market because they could not produce anything that was sufficiently friction-free. There is no reason why the manufacturer of apparatus of this kind, or a user of apparatus of this kind should be looking for outside assistance, though no doubt he might be thinking from time to time well, it would be nice if one could reduce the frictional effect; but there is not, so far as I am aware, any history of any specific problem. There is not anything pointing to this, that there would be some need for somebody within the relevant field to be looking for outside assistance. Of course, if they were, they might, I suppose, have gone to a bearing man, but they might have gone to some other sort of specialist who might be able to deal with friction problems. I think I would be prepared to accept that if once they went to the bearing man it is indeed likely that magnetic repulsion might be suggested as a possible solution to the frictional problems in this particular field.
29 The question of the addressee of the specification is unusually difficult in this case. Before the date of the patent, it seems that the persons principally concerned with sterilisation indicators were, unsurprisingly, microbiologists. …. The patentees say that the inventive step lay in the discovery that some enzymes present in bacteria (or bacterial spores) commonly used to test for sterilisation can survive (in the sense of still being active after) a sterilisation cycle which kills the micro-organism. The defendants say that this is obvious to any enzymologist, [the judge spelt out why]. …. So, in essence, the defendant's position is that it is all obvious to an enzymologist …
30 It seems to me that as a matter of principle invention cannot lie in bringing into a notional team working on a particular problem a new notional member with different skills from those of the existing notional team. The specification necessarily describes the attributes of the team to which it is addressed. Here, the team consists (notionally) of a microbiologist and an enzymologist. … The addressee of a specification is the person likely to have practical interest in an invention: here, it is the maker and seller of sterilisation indicators who wishes to make an indicator following the directions of the patent, and I am satisfied that for this purpose he employs a microbiologist with interests in the relevant area and an enzymologist who can carry out the directions of the specification. …
Mr Thorley submitted that if read as saying there can never be invention in bringing a different skill into a team for the purpose of obviousness, this passage was wrong. If on the other hand Pumfrey J was merely saying on the facts that the notional team would include an enzymologist, there was no problem. I am bound to say I think Pumfrey J was saying the former. And if so, I do not agree. It may be possible (I say no more) to explain the actual decision on the basis that the invention was simply obvious to an enzymologist.
I would add that although it has to be remembered that a specification may fail to provide sufficient details for the addressee to understand and apply the invention, and so be insufficient and invalid, it is often possible to deduce the attributes which the skilled man must possess from the assumptions which the specification clearly makes about his abilities.
The fact that Pumfrey J qualified this view by the words "often possible" may indicate that he was not saying that the person skilled in the art is taken to have the same skills come into play whatever topic of patent law is under consideration.
In some cases a patent claim may cover a wide field so that some parts of it will be obvious to the notional skilled person in one field and other parts will be obvious to the notional skilled person in another. That is not unfair to the patentee … but [is] simply a reflection of the fact that the scope of the protection sought is wide. I accept, of course, that in some cases there will be invention in marrying together concepts from two unrelated arts, but that is not what Mr Carr is arguing for here.
We would add one further comment here: there is an interrelationship between obviousness and insufficiency. At first blush one might suppose that an idea which requires masses of work to implement would be more readily rejected by, or less likely to occur to, the notional unimaginative skilled person/team who is the addressee than one which can be readily put into practice. This produces an apparent paradox: the less sufficient the description, the less is an idea likely to be obvious. The answer to the paradox is this: that if the notional skilled person/team is one that is prepared to contemplate an immense amount of work, that attribute must also be considered part of the person/team's consideration of what is obvious. Obviousness and sufficiency of description must be considered by the same person/team.
In the present case, however, the principle of introducing a rare earth chelate by a dyeing process quite clearly forms part of the solution to the technical problem to be solved (see points 3.4 and 3.5 above). The expert in dyeing cannot therefore be the skilled person who was faced with the task of solving the problem, because the very fact of choosing to introduce rare earth chelates by a dyeing process is the essential feature of the solution proposed. The board consequently takes the view that the skilled person faced with the task of solving the problem posed was not an expert in dyeing, but rather an expert in security materials who specialised in the marking (identification, authentication, etc.) and protection (against imitation, forgery or counterfeiting) of security documents and similar materials.
The idea of introducing rare earth chelates by a process of dyeing security fibres, etc., at a stage subsequent to their production - the process defined in claim 1 – is the essential part of the teaching of the contested invention as reflected in the solution to the problem posed. The technical problem addressed by an invention must however be so formulated as not to contain pointers to the solution, since including part of a solution offered by an invention in the statement of the problem must, when the state of the art is assessed in terms of that problem, necessarily result in an ex post facto view being taken of inventive step.
Suppose that there is a cloistered world of CSEM experts to whom the application of their marine craft to oil exploration was quite obvious, but whose views had not crossed into the realms of the actual oil explorers, and let it be supposed that the application of CSEM was in no way obvious to the latter. If Mr Burkill's submissions were correct, there would be a skilled addressee team of geophysicists, and the patent would not fail for obviousness; and the CSEM specialists would be prevented from doing something which is quite obvious to them. That seems to be wrong in principle, and that result is avoided if they are part of the team. If, next, one supposes that CSEM is not obvious to them, then their introduction to the skilled addressee team still does not render the invention obvious, and the new technique is truly inventive. Again, that is consonant with principle. The invention will result from marrying together two unrelated arts (to revert to what Laddie J said in Inhale) but that would be a correct result where the inventive concept would not be obvious to the practitioners of either. I stress that this part of the reasoning is not used to determine the constitution of the team; it is used to test the consequences of the arguments.
The correct approach in this case
The Place of Secondary Evidence
Being wise after the event counsel for the appellants pointed out that this was really an easy problem to solve …..
The whole history of this matter shows the falsity of that analysis. Dozens of inventors, and no doubt others as well, had tried and failed to find a satisfactory solution.
(a) What was the problem which the patented development addressed? Although sometimes a development may be the obvious solution to another problem, that is not frequently the case.
(b) How long had that problem existed?
(c) How significant was the problem seen to be? A problem which was viewed in the trade as trivial might not have generated much in the way of efforts to find a solution. So an extended period during which no solution was proposed (or proposed as a commercial proposition) would throw little light on whether, technically, it was obvious. Such an extended period of inactivity may demonstrate no more than that those in the trade did not believe that finding a solution was commercially worth the effort. The fact, if it be one, that they had miscalculated the commercial benefits to be achieved by the solution says little about its technical obviousness and it is only the latter which counts. On the other hand evidence which suggests that those in the art were aware of the problem and had been trying to find a solution will assist the patentee.
(d) How widely known was the problem and how many were likely to be seeking a solution? Where the problem was widely known to many in the relevant art, the greater the prospect of it being solved quickly.
(e) What prior art would have been likely to be known to all or most of those who would have been expected to be involved in finding a solution? A development may be obvious over a piece of esoteric prior art of which most in the trade would have been ignorant. If that is so, commercial success over other, less relevant, prior art will have much reduced significance.
(f) What other solutions were put forward in the period leading up to the publication of the patentee's development? This overlaps with other factors. For example, it illustrates that others in the art were aware of the problem and were seeking a solution. But it is also of relevance in that it may indicate that the patentee's development was not what would have occurred to the relevant workers. This factor must be treated with care. As has been said on more than one occasion, there may be more than one obvious route round a technical problem. The existence of alternatives does not prevent each or them from being obvious. On the other hand where the patentee's development would have been expected to be at the forefront of solutions to be found yet it was not and other, more expensive or complex or less satisfactory, solutions were employed instead, then this may suggest that the ex post facto assessment that the solution was at the forefront of possibilities is wrong.
(g) To what extent were there factors which would have held back the exploitation of the solution even if it was technically obvious? For example, it may be that the materials or equipment necessary to exploit the solution were only available belatedly or their cost was so high as to act as a commercial deterrent. On the other hand if the necessary materials and apparatus were readily available at reasonable cost, a lengthy period during which the solution was not proposed is a factor which is consistent with lack of obviousness.
(h) How well has the patentee's development been received? Once the product or process was put into commercial operation, to what extent was it a commercial success. In looking at this, it is legitimate to have regard not only to the success indicated by exploitation by the patentee and his licensees but also to the commercial success achieved by infringers. Furthermore, the number of infringers may reflect on some of the other factors set out above. For example, if there are a large number of infringers it may be some indication of the number of members of the trade who were likely to be looking for alternative or improved products (see (iv) above [I interpolate there does not seem to be a "(iv) above", but no matter].
(i) To what extent can it be shown that the whole or much of the commercial success is due to the technical merits of the development, i.e. because it solves the problem? Success which is largely attributable to other factors, such as the commercial power of the patentee or his license, extensive advertising focusing on features which have nothing to do with the development, branding or other technical features of the product or process, says nothing about the value of the intention.
… it will be necessary to go back to November, 1987 [the priority date] and try to understand the attitudes and thinking of those in the art at the time. That can best be achieved by looking at what was happening and the attitudes of those concerned in the field in the 1980s. Such evidence does, I believe, enable me to decide whether the opinions of the witnesses are consistent with the facts or hindsight reconstructions of the type which are not persuasive.
… the question of obviousness is probably best tested, if this be possible, by the guidance given by contemporaneous events.
In applying the statutory criterion [i.e. as to whether an alleged inventive step was obvious] and making these findings [i.e. as to obviousness] the court will almost invariably require the assistance of expert evidence. The primary evidence will be that of properly qualified expert witnesses who will say whether or not in their opinions the relevant step would have been obvious to a skilled man having regard to the state of the art.
And, a little later, after describing the danger of complications which can arise about secondary evidence, he added:
Secondary evidence of this type has its place and importance, or weight, to be attached to it will vary from case to case. However such evidence must be kept firmly in its place. It must not be permitted, by reason of its volume and complexity, to obscure the fact that it is no more than an aid in assessing the primary evidence.
These documents are treating the plaintiff's invention as both novel and inventive. They do not comment that it had been an obvious development from what had gone before. The defendants thought that the plaintiff's idea was worth copying. It was under these circumstances that the defendants chose to manufacture and market nappies incorporating the DFS system in infringement of the plaintiff's patent.
Conflicting expert opinion on obviousness
But just because the opinion is admissible:
it by no means follows that the court must follow it. On its own (unless uncontested) it would be "a mere bit of empty rhetoric" Wigmore, Evidence (Chadbourn rev) para. 1920. What really matters in most cases are the reasons given for the opinion. As a practical matter a well-constructed expert's report containing opinion evidence sets out the opinion and the reasons for it. If the reasons stand up the opinion does, if not, not.
I have no hesitation in repeating this. It cannot be emphasised enough. Reasons for the opinion are what really matter. It follows that it is generally not enough for the court to conclude that it accepts the opinion of one expert or the other. It too must descend into the reasons for the opinions.
Secondary Evidence – The Facts in this case
(a) Why not done before?
i) CSEM is only useful in deeper water (below 500m) because in shallower water radiation through the air interfered too much (air has very low conductivity). Whilst that is correct technically, people were looking for sub-sea hydrocarbons at a depth of greater than 500m by the late 70s and well below that not so long after.
ii) CSEM requires specialist apparatus and until the Patent there were only two teams (both academics) who had it. But Dr Chave gave evidence that the apparatus cost about US$1m. That is a trivial amount to an oil company. Cost of the apparatus cannot be a reason why the technique was not used for oil exploration in the manner proposed by the earlier.
iii) Some suggested that funding was a problem (e.g. a newspaper interview with Dr Srnka in 2004). But funding would surely not have been a problem if anyone had realised just what CSEM had the potential to do. The funds were not there because the invention was missed. No other explanation fits.
iv) It was not until the technique was proved to work that there was any real excitement. What mattered was not the idea but proof it worked. Mr Silverleaf sought to emphasise this, saying the real excitement (by those who expressed it – see below) only came about when the first trial off the coast of Angola showed it did. This is to my mind hopeless. If the idea was good enough to provide a "fair expectation of success" (see per Lord Hoffmann in Conor v Angiotech  UKHL 49,  RPC 716 at ) then why was it not tried earlier remains the question.
v) There were considerable improvements in computers and mathematical methods of analysis over the years making it easier in practice to use the idea by 2000. This cannot be an explanation though it was floated faintly and with no detail by Dr Chave. The fact is the technique was actually being used by the academics from the late 1970s. No one suggested that the very apparatus could not have been used for the inventors' purpose if anyone had had the idea.
vi) Hydrocarbon exploration companies were content with the major improvements which had been made with seismics and were not ready for CSEM. The Judge thought that was a possible explanation ( "reasonably well served by seismic techniques and in those circumstances had not had great cause to look at (for example) CSEM"). That will not do either. It is not as though seismics and CSEM were incompatible one with the other. Improving seismics could have gone hand-in-hand with the use of CSEM if anyone had thought of it.
vii) Insufficient demand for oil to make it worth adopting the technique. That cannot be the explanation. Once the demand warranted deep water prospecting it warranted the use of CSEM as part of the exercise.
 This material does not demonstrate clearly what factors were behind the take-up of marine CSEM in the period after 2000 but they suggest what some of them may have been. They suggest that better equipment and different techniques may have been among those reasons. Lack of funding for development also affected it previously. It may have been the case that the change in demand for oil played a part in resurrecting an idea that had previously have been thought to be not worth pursuing. I can make no clear finding about it. What I do find, however, is that I cannot infer from the take-up of CSEM in that period, when it had not been taken up before, that it was providing something novel or non-obvious in patent terms. There may be other explanations that were operating consistent with want of novelty.
He must have meant non-obviousness here (and in several other places) rather than "want of novelty" for he had made no finding of lack of novelty.
I think that the truer analysis is that the industry was being reasonably well served by seismic techniques, and in those circumstances had not had great cause to look at (for example) CSEM.
Looking with hindsight, the industry did have cause for looking at CSEM. It is a useful additional tool to seismics and would have been so years before the date of the Patent if anyone had thought of it or realised it could be used in that way.
(b) Pre- and Post- invention reactions of real skilled people.
(i) Prof. Constable
Statoil proposes the use of seafloor electromagnetic (EM) sounding as a fluid predictor over existing prospects. The seafloor EM method is not new - it has been in development for nearly 20 years and is being carried out by universities such as Cambridge, Toronto, and Scripps Institute of Oceanography. I personally have been active in this field for 16 years. The method works by injecting EM energy of around 1 Hz into the seafloor. Measurements of attenuation as a function of range and frequency provide estimates of seafloor resistivity. The proposed application to direct detection of hydrocarbons is, to the best of my knowledge, novel.
The conclusions of the model assessment are that if the target is not too small compared with its depth of burial, and the water depth is sufficient to suppress the air wave, then the controlled source signature of the oil-filled layer is detectable, yielding the controlled source amplitudes that are a factor of 2 to 10 different than for models without the oil layer. The signals are above the noise threshold, and the experimental parameters (frequency, range, antenna length, and power) are practicable.
There are weaknesses to the study: computer models of a 3D source and 1D target could have been carried out fairly easily with publicly [sic] available code, and one of the analogue model studies used radar frequencies and wave propagation rather than the diffusive propagation necessary to detect deep targets. However, the work took the group from almost no experience in this field to having a reasonable physical insight into the method. Their conclusions are not only basically correct, but they have discovered properties of the method known only to a very few experts (i.e. that the parallel/inline mode split is diagnostic of buried layers).
I used a 3D source/1D target code during my visit to verify Statoil's qualitative and quantitative conclusions. I would also note that the choice of controlled source EM is appropriate, as a thin resistive layer is invisible to other commonly used EM method, magnetotelluric sounding. In conclusion it is my opinion that the proposed method has a reasonable chance of success for sufficiently large targets (the type being suggested).
Should Statoil continue with this program it would be appropriate to commence field trials.
I wish Statoil every success in its endeavour; it is pleasing to see innovative research coming out of the industry sector.
However, I explained to Nancy Wilson (my contracts officer) that (a) this was a great research project that was going to make us all famous and that Scripps really ought to be associated with it.
I also pointed out that it was Statoil's idea and money making all this happen.
… vast saving of avoiding the costs of drilling test wells into structures that do not contain economically recoverable amounts of hydrocarbon
An important paragraph says:
The method relies on the large resistivity contrast between hydrocarbon-saturated reservoirs, and the surrounding sedimentary layers saturated with aqueous saline fluids. Hydro-carbon reservoirs typically have a resistivity of a few tens of ?m or higher, whereas the resistivity of the over and under-lying sediments is typically less than few ?m. In the following sections it will be demonstrated that this resistivity contrast has a detectable influence on SBL data collected at the sea bed above the reservoir, even though the hydrocarbon bearing layers are thin compared to their depth or burial. The effect of the reservoir is detectable in SBL data at an appropriate frequency, and if the horizontal range from source to receiver is of the order of 2-5 times the depth of burial of the reservoir in typical situations.
The significance of this is the demonstration, for the first time, that resistivity contrast can be used for thin layers of hydrocarbon: that the effects are detectable. The authors, including some of the few experts in the world on CSEM are presenting that as new information. As Mr Thorley put it, they were saying: "look we can do it with thin layers."
In the space of just a few years a new geophysical technique has appeared on the scene – marine controlled source electromagnetic (CSEM) sounding, also known as Seabed Logging by Statoil and R3M by ExxonMobil."
Actually, marine CSEM is not that new; Charles Cox of Scripps Institution of Oceanography proposed the method in the 1970s to compensate for the loss of MT signal at the deep ocean seafloor. By towing an EM transmitter close to the seafloor, EM energy couples well to seafloor rocks but, like the MT signal, gets absorbed quickly by seawater.
So why, if the method has been around for 30 years, has the exploration community just "discovered" CSEM? There are at least two reasons:
The first is that if the water depth is shallow compared with skin depth EM energy from the transmitter reaches the atmosphere where it becomes a true wave and propagates geometrically. This "air wave" rapidly becomes the dominant signal at the seafloor receivers and removes the sensitivity to seafloor geology that we have in deeper water. Thus until hydrocarbon exploration moved to water around 1000m deep, it was difficult to take advantage of the marine CSEM method
Second, it has long been known that the marine CSEM method is preferentially sensitive to resistive rocks (compared with MT methods, which are most sensitive to conductive rocks), and thin resistive horizons in particular. However, it was not until Statoil and ExxonMobil demonstrated that the method works with horizons as thin as oil and gas reservoirs that it became clear that marine CSEM could be used to discriminate resistive drilling targets from conductive ones. Of course, because oil and gas are resistive compared to sand and shale, this appears to provide direct detection capabilities.
Does marine CSEM work?
Undoubtedly yes, for big enough targets in relatively deep water. However, even though the method has been around for 30 years in the academic communities, the intensive application to continental shelf exploration is very new, and there is still a lot of work yet to be carried out to develop the interpretational skills and experience to get the most out of this method.
The take-home points:
? The marine CSEM method is not new, but the application to hydrocarbon is.
his later remarks might be thought to be less consistent with real novelty [again the Judge must have meant non-obviousness] than his first remarks might be said to be.
From an academic point of view, this project was an application of standard CSEM practice and represents no new techniques, just a novel target. However, I don't see any harm in introducing SBL as a terminology - I can appreciate that it looks good within Statoil, and it will probably help 'sell' the technique.
It is of course true that the invention represents the application of standard CSEM practice to a novel target. That was the very idea which had been missed for so long and which generated the enthusiasm shown by Prof Constable.
However, as someone who has worked in marine controlled source electromagnetic sounding (CSEM, aka 'seabed logging') for nearly 20 years, it is not clear to me what intellectual property Statoil is claiming in this regard. CSEM as practised off Angola is an innovation pioneered by Scripps Institution of Oceanography over 20 years ago, and indeed your colleagues visited me and Charles Cox in late 1998 to learn more about it from us. Also, the use of CSEM for hydrocarbon exploration has been advocated for some time, see for example Hoversten … and indeed appears in my proposals for my 'Seafloor Electromagnetic Methods Consortium' since at least mid-1998.
Given my considerable experience in CSEM and since Statoil's efforts to promote this field have been publicised …, it would be useful if you could be more precise as to the particular 'know-how and technology' that you are concerned about.
History does not relate what the answer was.
 EMGS put much stress on Prof Constable's apparent expressions of view in his peer review and subsequently. It seems to me that the court must be careful about the weight that is put on this sort of evidence. Prof Constable would probably have been qualified to be an expert in these proceedings. To place too much reliance on his expressed views on novelty (or, I suppose, against novelty had he expressed any clear ones) would be to admit extra expert evidence without leave, and, worse still, without proper testing in cross-examination. That would be true in any case where such evidence was relied on, but it is even truer in the present case where his later remarks might be thought to be less consistent with real novelty than his first remarks might be said to be. At one level he is not saying much which turned out to be particularly controversial at the end of the day. In his two later emails he stated that nothing new was done so far as the techniques were concerned. That was not disputed by EMGS - the actual CSEM techniques were not relied on as novel as far as the 019 patent is concerned. The most that Prof Constable said was new was actually pointing those techniques at hydrocarbon layers. The most he seems to be saying is that that had not been done before in fact (though he did say that others had thought about it). If he was getting excited about anything in his peer review letter then it was about no more than that. The question of whether that is true as a matter of fact, and if so whether that supports novelty, is a matter to be judged by reference to all the evidence and the prior art. If he was expressing a view on novelty in his peer review, it was seriously tempered by what he said about previous advocates of the idea in his last email. I think it just as likely that he was expressing keenness and encouragement because the oil industry was at last picking up and running with a ball that he had thought had been available for play for some time. All in all, therefore, the expressed but untested attitude of Prof Constable does not assist me much.
(ii) Prof Sinha and Dr MacGregor
 Dr Eidesmo first met Prof Sinha on 15th March 2000. They outlined to him their proposal to use Sea Bed Logging as a direct hydrocarbon indicator. Dr Eidesmo's evidence was that at no time did Prof Sinha suggest that he had thought of this approach before; on the contrary he was excited by the presentation, and thought it would work. I have seen Prof Sinha's note of the meeting. It reflects neither excitement nor a sense of déja vu. In a subsequent email of 31st March 2000 Prof Sinha agreed with a view apparently previously expressed by Dr Eidesmo:
"'I will say that in my opinion a positive field test will change dramatically the field of active source EM (and may be MT) because of the large impact this will have for the oil industry.' I'm continuing with some modelling, but nothing I've seen yet discourages me at all."
Take, for example, the reaction of Professor Constable after Statoil had presented this inventive concept to him. If he had felt that there was nothing in the concept, his report would have been very downbeat. Instead, it was the exact opposite. To quote a few telling passages:
"The seafloor EM method is not new … [but] the proposed application to direct detection of hydrocarbons is, to the best of my knowledge, novel."
"In conclusion, it is my opinion that the proposed method has a reasonable chance of success for sufficiently large targets (the type being suggested)."
"I wish Statoil every success in its endeavour, it is pleasing to see innovative research coming out of the industry sector."
Thus he expressly states that he thought the concept was new, and the way he speaks about it is not consistent with a view that it was obvious to him. This is not all, because we also know Professor Sinha was excited when Statoil presented the inventive concept to him – even Professor Sinha himself admits this. In cross examination he tried to rationalise this by saying that he was excited not at the concept but at the fact that an oil company were interested in it. However he then had to wriggle uncomfortably when he was asked to explain why, according to his own evidence, he went on to seek an explanation for Statoil's results so far and to speculate on what might be happening. This is the one point in Professor Sinha's testimony where I felt he was being less than convincing. I am satisfied his excitement reflected the fact that the concept had not occurred to him before.
If Professors Constable and Sinha were run-of-the-mill academics, these reactions might not carry much weight. However, they are two of a tiny handful of world experts in this technology. They clearly both found the concept exciting, so I do not for one moment believe they could have regarded it as obvious. If it was not obvious to two such eminent experts, it certainly cannot have been obvious to the unimaginative person skilled in the art who provides the proper legal test for obviousness. ….
From the evidence submitted, it is clear that Professor Sinha's and Dr MacGregor's interest in the subsea structure has been directed mainly towards geologically active zones at or near boundaries in tectonic plates. Although they refer to contacts and presentations to oil industry representatives in the late 1990s, they have not produced any evidence to show that they contemplated using EM methods for the direct detection of buried hydrocarbon reservoirs. In fact, Professor Sinha says in his first witness statement at para 36, that when he was asked in 1998 by LASMO, an oil company for whom he was doing some consultancy work, whether and EM survey could be used for direct hydrocarbon detection, he concluded that it would not be possible using magneto-telluric techniques. He did not apparently even consider whether CSEM techniques would work.
It seems from the evidence they have presented, that what Professor Sinha and Dr MacGregor were offering oil exploration companies in the late 1990s was primarily a method of detecting sedimentary layers below basalts. Basalt is relatively opaque to conventional seismic techniques, so a method which could "see through" the basalt overburden would be of great value to those interested in finding sedimentary layers as it is the latter which may contain hydrocarbon deposits. CSEM was being offered as a technique to achieve this. As basalt has a relatively high resistivity, what was being offered was a technique to detect a thin, relatively-conductive layer in a more-resistive substrate. I can find nothing in their evidence to suggest they had contemplated using CSEM to directly detect oil reservoirs in the present context, i.e. to detect a thin relatively-resistive layer of hydrocarbons within more-conductive substrate. Indeed, Dr MacGregor conceded in cross examination that she had not previously even considered this problem, and Professor Sinha also effectively conceded it when he admitted that at the March 2000 meeting he had initially been doubtful about whether a split would occur.
From this I conclude that Professor Sinha had not considered using CSEM as a means of directly detecting buried layers of hydrocarbon at the time of the meeting on 15 March 2000. That conclusion is, of course, consistent with the excitement he showed at the meeting and with his own admission that he discuss the split at some length during the meeting because he wasn't convinced it would exist. It follows that I am satisfied the requisite casual link is present.
 It is not disputed that Prof Sinha and Dr MacGregor gave evidence to the above effect. However, again this evidence has to be treated with caution. Again, putting a lot of weight on it is tantamount to admitting another two more experts without their evidence being properly tested in the context of this action. It also has to be noted, in the context of the 019 patent, that the actual invention in the Southampton patent relates to the split. There is no particular claim to the direct detection techniques, without the split, claimed in the 019 invention. There may be a number of reasons, not inconsistent with obviousness, why these two academics had not previously turned their minds to marine CSEM and hydrocarbons (if they hadn't), some of them demonstrating how clever it was and others demonstrating that they were thinking about something else. The application for the patent may demonstrate no more than their view that what was referred to was patentable, motivated by an attempt to get some financial benefit from it. Whether they are right about patentability is the question that arises in this action. They were certainly not saying the whole thing was old hat, but what else they should be taken as saying is more questionable. Accordingly, while there is material here that EMGS is entitled to rely on, it must be approached with caution. I do not, however, dismiss it from my consideration of the matter.
It is also clear to me as a scientist that this application step is not obvious. Beside the specific reasons I have given above, the most evident proof for this is that nobody actually saw this connection for almost a decade after this chapter [i.e. Chave] was written.
One is entitled to infer that Schlumberger had no real answer in the shape of one of their own employees who could explain why. Nor for that matter were they in a position to find an oil company geophysicist (whether still employed or retired) to give an answer.
CSEM –what's All the Excitement About??
The controlled source electromagnetic (CSEM) method may be the most significant new technology for oil and gas exploration since the development of 3-D seismic 20 years ago. The promise for the technology lies in its ability to differentiate resistive, potentially oil-bearing intervals from surrounding, more conductive water-bearing units. The principle is the same as that used in well logging devices to identify hydrocarbon zones in well bores. The technique is not new but the capability to resolve relatively thin resistive intervals in the depth domain offers new promise to lower risk through direct hydrocarbon indicators in conjunction with modern seismic methods.
Although Mr Peace refers to the principle being the same as in well-logging devices, the use there is over a very short range. Dr Brown produced a note for the Court indicating that it had a range of up to 2m and was performed down an actual borehole. Neither side made any points based on the existing knowledge of this technique.
Electro-Magnetic explorations methods have been around … as deep water marine methods since the mid-1990's when Marine MT was essentially declared a commercial exploration tool. These methods have however been rightly regarded as somewhat fringe geophysical methods of use only as regional exploration tools of low resolution and then only suitable for applications in certain more difficult geological provinces such as sub salt, sub basalts, sub carbonates etc.
However with the addition of higher frequency source and a change in the basic geophysical technique, EM methods have recently undergone a metamorphosis…
Mr Peace was not called and no explanation was offered as to why not. What he says about the way CSEM was regarded prior to the Patent is clearly important – it is more or less exactly the pre-Patent status of CSEM in the minds of exploration geophysicists for which Mr Thorley contended.
Obviousness over Chave
 The paper contains an introductory section which itself contains the following:
Recent developments in instrumentation and submarine geology have spawned increasing interest in the use of electromagnetic (EM) methods for seafloor exploration. Previously, little attention had been given to their use in the marine environment, due both to the success of the seismic techniques in delineating sub-surface structure and to a pervasive belief that the high electrical conductivity of seawater precluded the application of EM principles. Marine EM exploration of the solid earth has progressed substantially in academic circles over the past two decades; the adaptation of this technology for commercial purposes is only beginning.
Over three-fifths of the Earth's surface is covered by oceans. Even though petroleum is produced from huge deposits on the relatively shallow continental shelf, the immense area of the ocean represents a largely unexplored and an exploited resource base. Until recently, little economic interest was shown in the ocean floor environment ... however, the recent discovery of intense hydrothermal activity and poly-metallic sulphide deposits of unprecedented concentration and scale on the crest of the East Pacific rise ... has aroused interest in the possibility of deep-sea mining and spurred research into the mid-ocean ridge ore genesis as an analog to terrestrial occurrences ... While [ visual location is] capable of examining its surficial geology, they are not able to adequately assess the actual extent of the deposits and the nature of the geological structures in which they are found. Seafloor conductivity mapping is one of the few geophysical tools suitable for this purpose, just as the EM methods are one of the major geophysical techniques used in mineral exploration on land.
Over the past few decades, the search for petroleum reserves has been extended from the continent's off-shore into progressively deeper water, making the continental shelves a focus for geophysical exploration. The principal geophysical tool for this is the seismic method, and the success of the seismic approach is attested to by the level of offshore drilling activity and the subsequent production of oil. However, there are marine geological terranes [sic] in which the interpretation of seismic data is difficult, such as regions dominated by scattering or the high reflectivity that is characteristic of carbonate reefs, volcanic cover, and submarine permafrost. Alternative, complementary geophysical techniques are required to study these regions.
... This paper emphasises the differences between seafloor and terrestrial EM applications, especially with regard to noise, resolving ability, and apparatus....Most of the existing work on seafloor EM has been motivated by solid earth problems as opposed to exploration ones. The real data discussed reflect this difference, which is principally one of scale.
 There is then much discussion of the theories behind EM surveying, with a reference to TM and TE modes. This discussion is accompanied by a certain amount of algebra and a number of graphs. The relevant equipment is described. At page 947 of the publication Dr Chave turns to "Controlled Source EM Methods". The technique is described. He deals with the fact that thin resistive layers are relatively insensitive to the TE mode and at page 948 he deals with the nature of the transmission. He says:
"The choice of operating an EM system in either the frequency domain, transmitting a set of discrete frequencies one or a few at a time, or the time domain, transmitting a square or triangular step and measuring the transient response of the seafloor-ocean system, also exists. The physics of the two methods are identical, the response in one domain being the Fourier transform of the response in the other domain. Because of the finite and inexact nature of practical measurements, this transformation cannot usually be made outside the realm of theoretical studies. The choice of one system over another must be made on the basis of practical and logistical considerations."
 At page 950 Dr Chave turns to some modelling. His modelling seeks to demonstrate the effect of buried layers of differing resistivities on the signals generated by the sort of equipment shown in the patent.
"It is instructive to examine the behaviour of the horizontal electric field for geometric (range-dependent) and parametric (frequency-dependent) soundings in the presence of the simplest structural complication, a buried layer. In each case a specific model consisting of a half-space of conductivity 0.05S/m containing 1 km thick layers either 10 times more or less conductive and centered at depths of 1.5 and 5.5 km is considered; these values are intended only to be illustrative. Figure 16 shows the geometric sounding curves. The low conductivity zone behaves as a lossy waveguide which traps and guides the signal, resulting in slower attenuation with range when compared to the half-space case. The deep buried layer produces a smaller effect, as expected from the diffusion nature of EM induction, and requires a larger range for the trapping to become apparent. If the buried layer has a higher conductivity than the surrounding material, greater attenuation will ultimately result at long range, but the low conductivity waveguide created between the seafloor and the layer results in an increase in signal strength at intermediate distances. The HED [horizontal electric dipole] method is preferentially sensitive to relatively low conductivity zones due to the presence of the TM mode. The existence of a minimum usable source-receiver spacing of 1-3 times the burial skin depth, depending on the sense of the conductivity contrast, is also apparent. Longer ranges are required to detect low conductivity material. Figure 17 shows parametric sounding curves for the same model at ranges of 5 and 10 km."
 Figure 16 shows, by way of a graph, that the attenuation of the received signal, as one moves farther away than the transmitter, is less than where there is a uniform half space. The relative differences are less marked where the buried layer is deeper, but it is still shown to exist.
 Then the paper sets out details of the equipment developed at Scripps for conducting marine CSEM surveys and gives some information about experiments and surveys conducted. At page 958 it refers to an experiment in the ocean with an express reference to a basalt layer. At page 959 there is a reference to another survey involving a different system:
"The layout is based on the same frequency domain dipole-dipole system used for deep sounding, so the theory developed by Chave and Cox (1982) and Chave (1984b) is directly applicable. In particular, it may be shown that resistive features such as permafrost layers and basalt flows can be mapped using frequencies and source-receiver ranges attainable by the experimental system ..."
 The inventive concept in the relevant claims (there is no need to distinguish between them for these purposes) is the application of the CSEM techniques described in Chave to the search for, or identification of, hydrocarbon-bearing layers. The Chave paper does not go so far as to apply its techniques specifically to that end, but it contains all the other elements short of that. It models a marine CSEM survey and shows the anticipated result where a relatively resistive layer is sandwiched between two less resistive layers. It identifies the benefits of using a horizontal (as opposed to a vertical) electric dipole and identifies that the TM component of the signal is more sensitive to resistive layers. Where a CSEM survey is modelled in those conditions the refracted wave has the effect that one can detect the signals from the survey. The resistive layer operates as a sort of waveguide. Professor Schultz accepted that all that was present in the Chave paper. He also accepted that the authors of the paper had in mind the mapping of resistive layers. What is not present there is an express link with a search for hydrocarbon in a layer, and there is no express statement that the technique could be used for that purpose.
 So the missing step is the application of those marine CSEM techniques to a search for, or identification of, hydrocarbon layers. Dr Chave's evidence was that that step would be an obvious one for the skilled addressee to take, and I accept that evidence. Even if the paper is directed to other objects in terms of exposition (permafrost, and so on), it is general in its terms, and describes general techniques. Hydrocarbon layers are, for these purposes, just other resistive layers, albeit thinner than others under consideration. I think that Dr Chave is right about this. "
[147 I therefore find that the application of the Chave modelling technique to potentially hydrocarbon-bearing layers was obvious. That is the heart of the alleged invention. In his contemporaneous correspondence Prof Constable expressed the view that what was happening was the application of an established technique to a new target; I think that he was right. But the application to the new target was not, in patent law terms, inventive over the Chave paper.
Even if the application of CSEM to detection of hydrocarbons is not directly disclosed in Chave (which in my opinion it is) it would have been obvious to the skilled addressee reading Chave that the marine CSEM methods it describes may be used to search for hydrocarbon-bearing subterranean reservoirs and to measure the resistivity of reservoirs whose contents are not known.
Obviousness over MacGregor
There are numerous regions in the world where the presence of shallow high velocity layers makes the imaging of deeper structure using conventional seismic reflection techniques a difficult task. Of particular interest are continental shelf areas where potentially oil bearing sedimentary structures are obscured by layers of basalt, carbonate or salt. These high velocity layers limit the penetration of seismic waves and can cause reverberations which mask reflections from deeper sedimentary structures, leading to ambiguities in interpretation.
Additional constraint on the structure can be gained by studying the electrical resistivity. The resistivity of basalt, carbonate and salt is typically in the range 100-1000 ?m, whereas the resistivity of the surrounding sedimentary sequences are typically 1-10 ?m. This marked contrast provides an ideal target for electromagnetic prospecting techniques. By mapping such variations in resistivity many of the ambiguities inherent in conventional seismic techniques can be resolved. In addition sediment resistivity is in itself an interesting property to measure.
 …The focus is on resolving the extent of a highly resistive layer, which is basalt and not a hydrocarbon layer, but with the view of learning something about the layer underneath. As the introduction says, the model maps contrasts. It is finding out about the resistive layer between two less resistive layers, and also trying to find out about something underneath (including where it starts, in vertical terms). It is doing that by relying on signals that have taken a refracted route. It is obvious that that technique can be applied to layers other than basalt; and obvious that it is their comparative resistivities that are discernible. Although the relatively resistive layer in this case is not a hydrocarbon-filled layer, the application of these techniques to oil exploration is flagged by the references to "potentially oil bearing sedimentary structures" in the article itself. The technique in this paper was the utilisation of known physics, including the refracted wave through a known resistive layer. It was, in Dr Chave's view, which I accept, obvious to do it the other way round, that is to say to see if the effects of the refracted wave could be detected in order to see if it indicated a resistive layer, and to do that in the context of a sedimentary layer which was not beneath a more resistive layer.
Anticipation or obviousness over Srnka
Novelty – the Law
In order to be an anticipation the disclosure must be clear and unambiguous. I repeat the classic exposition in General Tire & Rubber Co. v. Firestone Tyre & Rubber Co. Ltd:
"To anticipate the patentee's claim the prior publication must contain clear and unmistakable directions to do what the patentee claims to have invented . . ."
"A signpost, however clear, upon the road to the patentee's invention will not suffice."
"The prior inventor must be clearly shown to have planted his flag at the precise destination before the patentee."
Every Act of Parliament must be approached with the conviction that its language is capable of a reasonable construction when carefully examined (Bismag v Amblins (1940) 58 RPC 209 at 232).
Items of prior art said to be novelty destroying are not of that kind. One has to consider how they would be understood on their date of publication (in this case 1986) by the notional person skilled in the art. There is no reason why such a person, just as in the case of a real person, must find a meaning. In real life there are documents which have no clear meaning, documents so obscure that one throws up one's hands saying "I have no idea what this author was really trying to say." The notional skilled reader can do likewise, and if he or she does, the document is not novelty-destroying. It is not "clear and unambiguous."
The Srnka disclosure
 The patent is entitled "Method and apparatus for offshore electromagnetic sounding utilising wavelength effects to determine optimum source and detector positions". The abstract reads as follows:
"An improved method and apparatus for electromagnetic surveying of a subterranean earth formation beneath a body of water. An electric dipole current source is towed from a survey vessel in a body of water substantially parallel to the surface of the body of water and separated from the floor of the body of water by a distance less than approximately one-quarter of the distance between the surface and the floor. Alternating electric current, preferably including a plurality of sinusoidal components, is caused to flow in the source. An array of electric dipole detectors is towed from the survey vessel substantially collinearly with the current source. Each electric dipole detector of the array is separated from the current source by a distance substantially equal to an integral number of wavelengths of electromagnetic radiation, of frequency equal to that of a sinusoidal component of the source current, propagating in the water. A gradient detector array is also towed by the survey vessel in a position laterally separated from, or beneath, the mid-point of the current source. Additionally, an array of three-axis magnetic field sensors mounted in controllable instrument pods are towed by the seismic vessel on the flanks of the current source. Frequency-domain and time-domain measurements of magnetic and electric field data are obtained and analysed to permit detection of hydrocarbons or other mineral deposits, or regions altered by their presence, within sub-floor geologic formations covered by the body of water".
 The section headed "background of the invention" contains, inter alia, the following:
"Electromagnetic survey systems are being used increasingly to explore for oil and gas on land. However, at present, practical methods for exploring for oil and gas in the offshore environment are restricted to the measurement of the natural magnetic and gravitational fields at the earth's surface, of the reflection of seismic energy from subsurface structures, or the seepage of chemical substances from mineral deposits beneath the sea floor into the sea water or atmosphere. Although passive techniques such as natural-source magnetotellurics can provide useful information about the lower crust and upper mantle, electromagnetic sounding techniques employing an active source are better suited for surveying subterranean formations within five to ten kilometres beneath the sea floor. Because practical techniques for active electromagnetic sounding of earth formations beneath the sea floor have not hitherto been known, the electrical structures of continental margins and offshore basins remain largely unknown, despite the scientific and economic importance of these areas….
'Resistivity' methods using an active source of direct electric current, or very low frequency alternating current…have been proposed for determining the apparent resistivity of geologic formations beneath the sea…"
 At column 3 there appears a "Summary of the Invention":
"According to the method of the invention, an electric dipole current source is towed from a survey vessel in a body of water substantially parallel to the surface of the body of water and separated from the floor by a distance less than approximately one-quarter of the distance between the surface and the floor. Alternating electric current is caused to flow in the source, said current including at least one sinusoidal frequency component. At least one electric dipole detector, including a pair of detector electrodes, is also towed from the survey vessel substantially collinear with the current source and spaced from the current source by a distance substantially equal to an integral number of wavelengths of electromagnetic radiation propagating in the water and having frequency equal to that of the sinusoidal component. A characteristic of the current emitted by the source and a characteristic of the potential difference between the pair of detector electrodes are measured. From these measurements, a characteristic of the "complex mutual impedance" of the current source and the dipole detector is determined. Preferably the current emitted by the source includes a plurality of sinusoidal components, each having a distinct frequency. Preferably, several dipole detectors are towed collinearly with the source. Measurements of the current characteristic and the potential difference characteristic should preferably be made at a plurality of frequencies for each source-detector pair…
"Potential difference measurements at the electrode pairs of the gradient array and dipole array, and magnetic field measurements at the magnetic field sensors, are made while the vessel is moving or stationary, and the measurements are interpreted to permit the detection of hydrocarbons or other mineral deposits, or regions altered by their presence, within sub-floor geologic formations covered by the body of water. Frequency-domain measurements of magnetic and electric field data are analysed to construct the complex impedance spectrum of the sub-floor formation beneath each survey station…"
 The real difficulties start to creep in in the section entitled "Description of the Preferred Embodiment":
"…The potential differences between [the source and transmitter electrodes] are measured and amplified, and thereafter further processed and recorded by electrical equipment…aboard [the] vessel. The measured data is interpreted in a manner to be discussed below, to permit characterisation of earth formation beneath floor of body of water and to locate regions in sub-floor formation which possess 'anomalous' properties indicative of mineral deposits. In a particular application, the measured data is interpreted to determine the presence and depth of a buried resistive layer, such as resistive layer 25, which has a resistivity different from the average resistivity of that portion of [the formation above that layer]."
Layer 25 is a reference to one of the drawings (I have omitted other numeric cross-references to drawings). It shows a layer below the overburden similar to the layer shown in the drawing of the patent. The italicised words in the above passages are my emphasis in order to identify terms which are important to the patent and which cause problems of interpretation.
 The description goes on:
"It is preferred that [the source dipole] and the electric dipole detectors be towed substantially collinearly, substantially parallel to [the] surface, and in approximately the lower quarter of the column of [the] water between [the] surface and [the] floor. As the depth below surface at which dipole current source and the dipole detectors are towed decreases to less than three-fourths the distance between the floor and the surface, the strength of the signal at the dipole detectors which is indicative of the electrical resistivity of the sub-floor formation (the 'anomaly' signal) rapidly decreases due to masking by the water between the floor and the dipole detectors. It is additionally desirable to tow the apparatus within the lower quarter of the column of water between surface and floor because in that region, the sensitivity of the anomaly signal to the height above floor at which the apparatus is towed is sufficiently weak that fish need only control the actual tow depth to within about 5% of the desired tow depth".
"If [the source electrodes] are separated by a first distance, and adjacent pairs of [detector electrodes] are also separated by substantially the first distance, then for direct detection of buried resistive layer located a second distance D, below floor, the mid-point of current source and the mid point of one of the electric dipole detectors should be separated by at least two D and preferably should be separated by at least three D. Also for detection of [the] buried layer, the output current at [the source dipole] should preferably include a sinusoidal component having frequency equal to the 'skin depth frequency' associated with [the] buried resistive layer. Such skin depth frequency [and here the patent sets out the skin depth formula referred to above]…is that frequency which makes the electromagnetic skin depth in the [overburden] equal to the depth, D, of the buried resistive layer". [This recitation omits the cross-referencing to the drawing but is sufficiently clear without it.]"
"…I have found that the influence of the electromagnetic coupling directly between [the] source and each dipole detector (which coupling is independent of the characteristics of earth formation [in the overburden]) on the potential difference measurements at such dipole detector may be desirably reduced by spacing each such dipole detector from the source an integral number, n, of wavelengths ?w, of the electromagnetic signal from [the] source. Wavelength ?w is given by [a given expression]. If [the source and detector] are so spaced from each other, all of the changes in the phase of the signal measured at each detector (relative to the phase of the output current at [the] source) are due to electromagnetic signals propagating along or below [the] floor…"
"If it is desired to make the surveying system particularly sensitive to a resistive layer buried at a depth D below the floor, and if the average conductivity…of [the overburden] is known to a depth just above depth D, then the separation between [the source and detector] should be chosen to be substantially equal to an integral multiple of 2pD(??s)½ and the source current should be chosen so as to include a sinusoidal component having frequency substantially equal to the skin depth frequency associated with depth D".
"It is desirable to generate, from the potential difference measurements made at each dipole detector, a signal indicative of the complex mutual impedance of [the source and detector]. From analysis of variations or 'anomalies' in the phase and amplitude of such complex mutual impedance signal, the presence of a buried resistive layer such as [the layer shown in the drawing] may be determined. I have found that the depth to such buried layer may be estimated by employing a plurality of detector dipoles in the electric dipole detector array and employing a variable frequency dipole source, and making potential difference measurements at each detector for each of a plurality of distinct source frequencies. In particular, it has been found that the frequency at which the phase or amplitude anomalies indicative of [the] buried layer are at a peak (or maximum) will decrease as the separation between source and detector increases, until such separation increases to a critical separation equal to three times the depth of [the] buried layer beneath [the] floor. Beyond such critical separation, the value of source frequency giving the peak signal anomalies remains substantially constant. By determining the value of such substantially constant frequency…the depth of [the] buried resistive layer may be estimated as…"
 Srnka relies on "complex mutual impedance". In technical terms that means:
"the linear relationship between the EM field and a source current for a given frequency source receiver offset in geometry." (Dr Chave)
In more everyday terms it can be viewed as the strength and phase of the received signal. The complex mutual impedance instructions involve comparing the amplitude and phase of the received signal with the amplitude and phase of the source signal. They will vary in accordance with the frequency and in accordance with offset.
Novelty of the Patent over Srnka
Q. I think we have agreed that Srnka enables you without the difficult bits of the teaching to set up and carry out a marine CSEM survey looking for buried resistive layers?
A. Well, by removing what I think are some of the essential bits of the teaching, you have a very generic statement of a source and a receiver and multiple frequencies that seems to be a very standard bit of practice as of 1986.
Q. And it specifically tells you to do this, to go and look for hydrocarbon reservoirs which are buried resistive layers, does it not?
A. Well, the patent, in its totality, tells you that. You have now asked me to remove big sections of it. Whether it would be effective in so doing by removing those sections I think is a matter of great conjecture.
Q. You have just read those sections. I have not asked you to remove any of the sections which refer to hydrocarbon reservoirs; so that bit of the teaching is unaffected by what I asked you to do, is it not?
A. Well, I mean, I do not know how to respond. It just seems a nonsense to me to even pose that; to cherry pick sections of a document whose stated aim is to do one thing, remove teaching on how to achieve big aspects of that and then ask me to conclude, "Well, it is still telling us to do it". No, it is a different document then. I must consider it in its totality.
Q. You would agree that Srnka in its reduced form, as we just discussed, includes within it the indicator for resistive or not resistive – the indicator for hydrocarbon or not that 019 has?
A. I am no longer sure what it means having excised those sections that you have asked me to pretend do not exist. All it then says is, "I am aware that there can be resistive layers. I am going to set up a generic CSEM experiment and through some method to be determined I will say something about whether the layer can be detected." That is about all it says when you take out all of the relevant bits you have asked me to take out. I really do not think it is saying anything other than that.
Q. But all of which you agree was conventional at this date?
Dr Chave's new interpretation was that "anomaly" and its derivatives meant a difference between the reading that one got on site with a buried layer and the reading one would expect to get if there were no resistive (or perhaps conductive) layer, the latter being based on a known physical reference survey or a model. He did not give reasons for his newly-expressed view. He did, however, strongly defend it in cross-examination. In doing so he is likely to have been influenced by some modelling that he did which, he said, demonstrated that "anomaly" in his sense did coincide with the results of modelling - one could see the results and effects that Srnka described.
Obviousness over Srnka
 It is obviously a problem with Srnka that its detailed teaching is somewhat unclear and obscure. If it stood by itself that lack of clarity, and that obscurity, would almost certainly stand in the way of an obviousness claim, or at least an obviousness claim based on the detailed teaching. But it does not stand alone for these purposes. I have already found the central teachings of Chave to be common general knowledge. This includes teaching of the refracted wave. If Mr Burkill is right that that paper does not disclose the application of the known physics to the direct detection of a hydrocarbon layer, then in my view Srnka does. Its text makes it plain that it is concerned with detecting the presence (as well as the depth) of hydrocarbon layers, even though other things are mentioned, and even though it is not plain how that is to be achieved in practice. Accordingly, if the invention is not obvious over Chave because the missing element of seeking hydrocarbon layers is not an obvious application (contrary to my primary view) it is obvious over Srnka when Srnka is placed against the permissible background of the common general knowledge elements of Chave. I accept that there was no direct evidence from Dr Chave on that particular way of putting the case, but it is a conclusion that I consider I am entitled to draw on the basis of the very extensive evidence that was given about Srnka, the Chave paper and common general knowledge. If there is a gap in between the Chave paper (embodying common general knowledge for these purposes) and the invention of the kind suggested by Mr Burkill in his description of the inventive step, then it is, in effect, filled by Srnka.
(a) The very fact that Srnka is so obscure in meaning as not really to have one is a very telling factor against obviousness. Even read with the knowledge of the CSEM technique (which a CSEM expert would have had in 2000, and indeed would have had years earlier) the most one could get would be a suggestion that some unintelligible technique might be useful for "detection of hydrocarbons." I do not see that as telling anyone, including a CSEM person, that the standard CSEM method could differentiate between identified thin layers which might contain hydrocarbon or might contain water/brine.
(b) It entirely overlooks the fact that although Srnka had belonged to and been abandoned by a mighty oil company and had been widely discussed by CSEM experts, nothing had come of it. It is not as though Srnka was an obscurely published document. In its time it was before the very eyes of all the sorts of people to whom it is said it would have made the invention obvious. The position had not changed over the years.
(c) A case of obviousness by a combination of Chave and Srnka overlooks the fact that whatever Srnka is talking about is not conventional CSEM and is inconsistent with it. To say that the unimaginative skilled person (whether CSEM expert or exploration geophysicist) would have the wit to ignore the core Srnka teaching is going too far.
Anticipation by Yuan?
… the matter relied upon as prior art must disclose subject-matter which, if performed, would necessarily result in an infringement of the patent. …. it follows that, whether or not it would be apparent to anyone at the time, whenever subject-matter described in the prior disclosure is capable of being performed and is such that, if performed, it must result in the patent being infringed, the disclosure condition is satisfied. The flag has been planted, even though the author or maker of the prior art was not aware that he was doing so.
(a) Yuan is not concerned with a "hydrocarbon containing submarine reservoir" within the meaning of the claims in dispute (1 and 1A as proposed to be amended).
(b) Yuan is not concerned with:
(i) "searching for a hydrocarbon containing submarine reservoir" within the meaning of claim 1;
(ii) "determining the nature of a submarine reservoir" within the meaning of claim 1;
(iii) "performing a survey .. to determine whether a submarine reservoir … contains hydrocarbon or water," within the meaning of claim 1A.
(c) Yuan is not enabling.
(d) Yuan does not make her determination "based on the presence or absence of a refracted wave component."
(e) Yuan does not necessarily involve operating within the parameters l (transmitter/receiver distance) and ? (wavelength) of claim 1.
The Disclosure of Yuan
 This is a "poster presentation" given at the American Geophysical Union meeting in San Francisco in December 1998. A "poster presentation" is in effect a paper which is "delivered" by its being placed on a large board so that those interested can read it and, if they think fit, copy it. It is entitled "Electromagnetic assessment of offshore methane hydrate deposits in the Cascadia margin" and it is by J Yuan, G Cairns and R N Edwards. …
 Methane hydrate is an ice-like white solid. It is, as its name suggests, a form of methane in a sort of ice-like form. Technically, it is a "clathrate" i.e. gas molecules encased in water molecules. It is perhaps, in the future, a potential source of methane, though at the moment no-one knows how to extract it economically and practically. At present it is a nuisance to drilling. It occurs in sedimentary layers. Technically it is a hydro-carbon.
 Yuan contains the following. It starts with a section entitled "Importance of Assessment" and says:
"The assessment of off-shore methane hydrate is relevant because the deposits are expected to become a very important natural energy resource…."
Under the problem of "assessment", she says:
"It is difficult to assess the total mass of hydrates from conventional geophysical remote sensing. While the base of hydrate deposits stands out clearly on seismic sections as the Bottom Simulating Reflector (BSR), the diffuse upper boundary is not well delineated.
"Our group is developing a number of complementary geophysical techniques, one of which, the use of an electromagnetic method, is described here."
 Next is a section entitled "Refraction electromagnetics":
"Marine sediment conducts electrical current ionically through saline fluid present in interconnected pores and fractures. Methane hydrate, like ice, is electrically insulating. Deposits of hydrate in sediment replace the conductive pore water, restrict the flow of electric current and thereby increase the bulk resistivity of the rock. Refraction electromagnetic data are obtained by measuring the analogue of the time taken for an electrical disturbance generated in a sea floor transmitter to diffuse through the sediment to a sea floor receiver (Edwards 1997). The travel time is related linearly to the resistivity: the higher the resistivity the shorter the travel time. The analog used is the phase difference between the transmitted and received signals viewed as a function of frequency. In simple terms, a linear variation in phase difference with frequency between the transmitted and received signals corresponds with a simple time delay and may be converted to an apparent resistivity."
 Next there is a section entitled "Electrical conductivity of hydrate" which I do not need to quote save for the last sentence:
"The amount of hydrate present can be directly related to conductivity."
 Under "apparatus" Yuan sketches a conventional marine CSEM setup and refers to the prior art Chave paper. The diagram shows one transmitter and two receivers.
 Yuan apparently conducted a 10 day experiment on board ship in 1998 off Canada's west coast.
 The paper then goes on to show the result of some modelling, demonstrating apparent resistivity and phase differences for a transmitter/receiver separation of 500 metres. Details of the survey are then given and there is shown "apparent resistivity computed using the phase difference method for transmitter receiver separations of 85, 185, 200 and 300 metres…." The actual results are then graphed. The first graph (fig.9) is entitled: "Recorded stacked transient signals on the sea floor and in the water column". The data analysis section declares that:
"Using this scheme we inverted all data in frequency domain with half space models."
 Fig.10 is:
"A plot of the difference in phase measured at a given site and the phase of the signal in the water column against corresponding theoretical models having a variable sea floor conductivity."
 The conclusions include the following:
"1. We have designed and constructed a marine sea floor transient electric dipole-dipole apparatus suitable for assessing offshore methane hydrate.
2. The apparatus has been tested successfully over known hydrate deposits west of Vancouver Island.
3. Estimates of apparent electrical resistivity of the sea floor have been obtained with an experimental accuracy of better than one per cent for a wide range of transmitter-receiver separation using a differential phase analysis method.
4. Preliminary results reveal that the resistivity of the sea floor is remarkably uniform at about 1.15 ohm.metres to a depth of in excess of 100 metres. There is some evidence for higher resistivity values near [a relevant site] which may indicate the presence of hydrate."
(a) The meaning of "hydrocarbon containing reservoir" (I leave out submarine which adds nothing in this debate)
The question is always what the person skilled in the art would have understood the patentee to be using the language of the claim to mean (per Lord Hoffmann in Kirin-Amgen  UKHL 46 at .
It merely has to be capable of containing something (namely fluids). A reservoir can be an empty reservoir. I think that it is used in that sense in the 019 patent - see the opening sentence, which uses the word broadly.
And at :
It is a reservoir because of its porosity, which is capable of holding a fluid. The methane hydrate is a hydrocarbon, literally speaking. So sediment containing methane hydrate in its pores is literally a reservoir which contains a literal hydrocarbon.
(b) Was Yuan "searching" or "determining the nature of"?
(c) Is Yuan enabling?
Does Yuan base her determination on the refracted wave component?
seeking, in the wave field response, a component representing a refracted wave, and determining
[claim 1] the presence and/or nature of any reservoir identified based on the presence or absence of a refracted wave component
[claim 1A] whether the reservoir contains hydrocarbons or water based on the presence or absence of a refracted wave component.
 So far as using the refracted wave is concerned, it is not plain that Yuan was using that either. It is true that there is a section of the paper called "Refraction Electromagnetics"; it is true that one of the physical aspects of refracted waves, namely the quicker transmission of signals, is relied on, and it is true that the refracted wave is always there (in terms of physics, as Dr Chave pointed out) but it is not clearly exploited in the manner in which the 019 patent seeks to exploit it. This paper is much more focussed on measuring bulk resistivity and modelling results. Again, therefore, the paper does not anticipate.
I accept that entirely.
(e) Does Yuan disclose working within parameters of the claims?
She shows a model in accordance with various frequencies, but her actual frequencies are not used. Her modelled frequencies, when "plugged into" the relevant formulae, show a wavelength range of 575 to 32,000m. When those wavelengths are applied to the offset formula in integer 10 of claim 1, this would give a range of offsets from 288m to 320 Km. There is a slight overlap between the top of Yuan's actual ranges and the bottom of the ranges generated with integer 10.
"Integer 10" is the formula at the end of claims 1 and 1A: 0.5 ? = l = 10 ?.
Conclusion on Yuan
Lord Justice Sullivan:
Lord Justice Waller: