Whether Public Viewing Amounts to Enabling Disclosure is Context Dependent

Betser-Zilevitch v PetroChina Canada Ltd 2021 FC 85 Manson J

            2,584,627 / Steam-Assisted Gravity Drainage

In this decision, that turned primarily on claim construction, Manson J held the 627 patent to be valid but not infringed. There is no new law, but the decision illustrates that the claims may be construed with reference to the function of the invention, and that whether public viewing of the prior art amounts to prior disclosure is context dependent.

The 627 Patent generally relates to a modularized (Steam-Assisted Gravity Drainage) SAGD well pad for heavy oil (bitumen) production [10]. A “well pad” is a collection of well pairs used in extraction of heavy oil production. “Modularized” means that the well pad is made off-site in modules that are then transported to the well site and assembled. This is in contrast to “stick built” well pads that are entirely constructed on-site. Construction of a well pad is a major undertaking that takes months. The main advantage of modularization is reduced costs flowing from reduced on-site construction costs [7]. The well pad has several levels, which, as I understand it, are like floors in a building, except that the levels are open. The key aspect of the 627 patent was that the main flow lines were on the “first level” [12], [116], [117].

In the defendant’s allegedly infringing well pads the production flow lines were located on a higher level, which requires scaffolding for workers in the field to access, and not on the lowest level [135]. The key claim construction issue was therefore as to the meaning of “first level” in the claim. The experts disagreed as to the meaning of the term. In light of the “ambiguity” in the claims, Manson J held that the term “would be understood with reference to its functions and objects, as provided in 627 Patent specification” [116]. The object was to constrain the placement of the flow lines at a level such that they would be connected without the need for scaffolding, thus improving safety and reducing costs [116]–[118]. This illustrates that reference to objective of the invention may be useful to construe the claims.

Because Manson J held that there was ambiguity, he didn’t need to address the question of whether recourse to the disclosure is appropriate even in the absence of a finding that the claims are ambiguous. I can’t resist digressing on this point. In my view, recourse to claims is always appropriate: as Lord Hoffmann pointed out in Kirin-Amgen [2004] UKHL 46 [33], the skilled person “reads the specification on the assumption that its purpose is both to describe and to demarcate an invention.” Words take their meaning in part from the context in which they are used; the common general knowledge is part of the context, and I can’t think of any reason why the disclosure should not also be considered part of the relevant context. Since the disclosure and claims are both part of the specification, a skilled person reading the claims would have to make an effort to avoid seeing the disclosure, and I can’t think of any justification for such an artificial approach. In this case, Manson J found an ambiguity allowing recourse to the specification on the basis of a disagreement between the experts as to the meaning of the terms. If that is all it takes, then we might as well just recognize that consideration of the disclosure is always appropriate in claim construction.

An issue that arose in respect of obviousness was the relevance of prior art modularized well pads that had been transported on public roads and parked uncovered in a public parking lot [159]. The patentee argued that that “[m]erely viewing, without more” is not enough [164] relying on Bombardier 2017 FC 207 [490]. Manson J noted that “The degree of scrutiny required upon visual inspection is context specific. The level of scrutiny required to discern the external elements of a skate in a public arena, as in Bauer Hockey FC [2010 FC 361], above is evidently higher than the scrutiny required to view the components of a large SAGD module” [165]. The point, as I understand it, is that in order to be set up in an anticipation or obviousness attack, the prior art must have been become “available to the public” before the relevant date, and the information which is the quid pro quo for the patent is made available only if the requirements for enabling disclosure are satisfied. A view from a distance of a well pad in which flow lines are visible may be an enabling disclosure, even though a view from a distance of hockey skates does not provide an enabling disclosure of the details of the fabrication method.