IP Law Daily Noninfringement judgment over hydraulic fracturing methods affirmed
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Tuesday, March 31, 2020

Noninfringement judgment over hydraulic fracturing methods affirmed

By Brian Craig, J.D.

The district court properly construed the patent claim "polymer-continuous liquid phase" as a single phrase.

Concluding that the federal district court in Marshall, Texas, properly construed patent claims concerning hydraulic fracturing methods, the U.S. Court of Appeals for the Federal Circuit has affirmed the district court’s stipulated judgment of noninfringement. The Federal Circuit concluded that it had jurisdiction to consider an appeal involving a stipulated judgment of noninfringement where the judgment resolves the infringement issue. The appeals court also found no error with the district court’s construction of the claim "polymer-continuous liquid phase" to constitute a single phrase (EnerPol, LLC v. Schlumberger Technology Corp., March 31, 2020, Stoll, K.).

EnerPol, LLC accused Schlumberger Technology Corporation of infringing certain claims of U.S. Patent No. 6,949,491 directed to hydraulic fracturing methods. Hydraulic fracturing, sometimes called fracking, is used in oil and gas well development. Following the district court’s claim construction decision, EnerPol moved for entry of final judgment of noninfringement. EnerPol also filed a stipulation of inability to prove infringement and a proposed final judgment. The district court then entered a stipulated judgment of noninfringement in favor of Schlumberger. In its decision, the district court concluded that based on the claim language and specification, the term "polymer-continuous liquid phase" should be construed as a single phrase. The district court also construed "continuous liquid phase" in the patent claim. EnerPol challenged the district court’s construction of two disputed claim terms. Schlumberger cross-appealed requesting dismissal of EnerPol’s appeal for lack of appellate jurisdiction.

Jurisdiction. The appeals court first rejected Schlumberger’s argument that the stipulated judgment of noninfringement deprived the Federal Circuit from considering the appeal. Where a claim construction order does not resolve the issue of infringement, it is not a final decision, and, accordingly, is not appealable. Schlumberger argued that EnerPol’s appeal should be dismissed because the district court’s judgment does not clearly or specifically explain how the district court’s constructions led to the noninfringement judgment, thus rendering any opinion by the Federal Circuit modifying those constructions advisory only.

The Federal Circuit distinguished its previous holding in Jang v. Boston Scientific Corp., 532 F.3d 1330 (Fed. Cir. 2008) that a judgment is reviewable only if it is possible for the appellate court to ascertain the basis for the judgment challenged on appeal. In the present case, the final judgment specifically identifies both the asserted patent claims and the particular claim constructions impacting those claims. The district court construed the disputed claim term of "polymer-continuous liquid phase" as a single phrase with a single meaning. The district court’s judgment was indisputably based on that single phrase. Because the noninfringement judgment in this case resolves the infringement issue and thus constitutes an appealable final judgment, the Federal Circuit had jurisdiction to consider the appeal.

Claim construction. The Federal Circuit also held that the district court properly construed the terms "polymer-continuous liquid phase" and "continuous liquid phase" in the patent claims. The construction of claim terms is based on the claim language, the specification, and the prosecution history. The Federal Circuit agreed with the district court’s construction of "polymer-continuous liquid phase." The district court held that "polymer-continuous liquid phase" requires "polymer in a liquid state that is greater than fifty percent by volume of the fluid that does the fracturing in the formation. The claim language, specification, and prosecution history all support this construction. Each time the specification refers to a "polymer-continuous liquid phase," it describes the polymer converting from a solid to liquid before being displaced out of the wellbore and into the rock formation. The specification also repeatedly uses the terms "continuous" and "external" synonymously when describing the degradable polymer, further supporting the district court’s construction that the polymer be in a liquid state so that the polymer can be external in the fracturing fluid.

Furthermore, the district court construed "continuous liquid phase" to also mean "polymer in a liquid state that is greater than fifty percent by volume of the fluid that does the fracturing in the formation. There was no dispute that the term "continuous liquid phase" should be interpreted to have the same meaning as "polymer-continuous liquid phase."

Therefore, the Federal Circuit affirmed the district court’s construction of the claim terms and the stipulated judgment of noninfringement.

This case is Nos. 19-1079 and 19-1120.

Attorneys: Robert P. Courtney (Fish & Richardson PC) for EnerPol, LLC. Maximilian A. Grant (Latham & Watkins LLP) for Schlumberger Technology Corp.

Companies: EnerPol, LLC; Schlumberger Technology Corp.

MainStory: TopStory Patent GCNNews FedCirNews

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