Search Team

Search by Last Name

Canrig Drilling Technology Ltd. v. Trinidad Drilling L.P.

Area of Law:

Patent Infringement


1. Defendant sought to preclude the testimony of Plaintiff’s non-obviousness expert, Keith Womer, on the ground that it was not based on sufficient facts or data.
2. Plaintiff sought to preclude the testimony of Defendant’s expert witness, Arthur Zatarain, on the grounds that it would not be helpful to the jury and was not relevant to issues in the case.
3. Plaintiff sought to preclude the testimony of Defendant’s damages expert witness, Thomas Britven, on the grounds that he did not reliably apply his methods to the facts of case.


1. Denied.
2. Granted in part and denied in part.
3. Denied.


Opinions of Keith Womer:
The court declined to preclude Keith Womer’s testimony that the asserted patents were non-obvious.  Womer opined that the asserted patents were not obvious in light of secondary consideration evidence for one of Plaintiff’s products.  Slip op. at 14.  Defendant argued Womer’s opinions should be excluded because there was no evidence that Plaintiff’s product embodied the asserted patents.  Id.  The court noted that Womer was entitled to assume the underlying facts on which he based his opinion, and that Defendant failed to ask any questions on the issue during Womer’s deposition.  Id. at 15.  Defendant’s recourse was to cross-examine Womer at trial regarding the basis for his assumption that the product at issue embodied the asserted patents.

Opinions of Arthur Zatarain:
The court granted in part and denied in part the motion to exclude Arthur Zatarain’s testimony regarding proper claim construction and inequitable conduct on the part of Plaintiff.  The court ruled because the risk of confusing the jury was high when an expert opines on claim construction, Zatarain would not be permitted to “present to the jury any opinions regarding proper claim construction.”  Id. at 16.

The court and both parties agreed that opinions regarding inequitable conduct were not “relevant to any issue in the case.”  Id.  Defendant argued, however, that statements Zatarain’s expert report that related to issues other than inequitable conduct should be admissible.  The court agreed and ruled that Zatarain could testify regarding his opinions that were not directed to inequitable conduct.  Here, that meant that Zatarain could testify that certain prior art was not before the PTO, but he could not testify as to why that art was not before the PTO.  The court also noted that Zatarain would not be allowed to “speculate regarding whether the PTO would have reached a different result if all relevant prior art references were before it.” Id. at 17.

Opinions of Thomas Britven:
The court declined to exclude Thomas Britven’s testimony regarding the appropriate royalty.  Plaintiff made several objections to calculations Britven used in an analytical approach to calculate a reasonable royalty.  Britven’s calculations compared profitability in various scenarios.  Plaintiff argued that because Britven’s calculations did not account for all the variables that may have affected profitability, they should be inadmissible. The court disagreed but noted that Plaintiff’s arguments were “relevant to the appropriate weight to which Britven’s opinions may be entitled.”  Id. at 19.

Plaintiff also argued that Britven’s consideration of a certain license agreement was inappropriate because he had no basis for his assumption that it was comparable.  Id. at 20.  The court noted again that an expert is entitled to assume underlying facts, and that it would be up to Defendant to prove the underlying assumptions at trial, subject to Plaintiff’s cross-examination.