Enercorp Sand Solutions Inc. v. Specialized Desanders Inc.

1. Case Identification

• Case #: IPR2018-01748
• Patent #: 8,945,256
• Filed: September 17, 2018
• Petitioner(s): Enercorp Sand Solutions Inc.
• Patent Owner(s): Specialized Desanders Inc.
• Challenged Claims: 1-16

2. Patent Overview

• Title: Desanding Apparatus and System
• Brief Description: The ’256 patent discloses a system for removing particulates, such as sand, from fluid streams produced from oil and gas wells. The invention uses an elongated, inclined vessel that leverages gravity to separate solids and liquids from a gas stream, with the inclination being a key feature intended to improve separation efficiency and ease of cleaning compared to prior horizontal designs.

3. Grounds for Unpatentability

Ground 1: Obviousness over Hemstock and Davis - Claims 1-7, 9-11, 13, and 16 are obvious over Hemstock in view of Davis.

• Prior Art Relied Upon: Hemstock (Patent 6,983,852) and Davis (a 1985 article titled "Sedimentation of Noncolloidal Particles at Low Reynolds Numbers").
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner asserted that Hemstock, which shares an inventor with the ’256 patent, taught nearly all limitations of the challenged base claims. Hemstock disclosed a horizontal desanding vessel with a fluid inlet, a spaced-apart fluid outlet, an upper freeboard portion, and a lower belly portion for collecting solids. The only key element not explicitly disclosed in Hemstock was the vessel's non-zero inclination. Petitioner argued that Davis, a foundational paper on sedimentation principles, explicitly taught that inclining a settling vessel was a well-known and effective technique to enhance solid-liquid separation rates by increasing the available surface area for settling.
  • Motivation to Combine: A POSITA would combine Hemstock's desander with the inclination taught by Davis to achieve a predictable improvement in performance. The primary goal of a desander is to efficiently separate sand, and inclining the vessel would achieve more rapid settling, thereby reducing the re-entrainment of solid particulates into the outgoing fluid stream. This desire for improved efficiency provided a strong motivation for the simple modification.
  • Expectation of Success: A POSITA would have had a reasonable expectation of success in this combination. The proposed modification involved applying a well-understood physical principle (enhanced gravity settling in an inclined channel) to a known apparatus (the Hemstock desander) to achieve an expected and desirable result (faster and more efficient separation).

Ground 2: Obviousness over Hemstock, Davis, and Miller - Claims 8, 12, 14, and 15 are obvious over the combination of Hemstock, Davis, and Miller.

• Prior Art Relied Upon: Hemstock (Patent 6,983,852), Davis (1985 article), and Miller (Patent 1,458,234).

• Core Argument for this Ground:

  • Prior Art Mapping: This ground built upon the inclined vessel combination of Hemstock and Davis and added Miller to teach limitations found in the dependent "Inclination Angle Claims" (8, 12) and "Eccentric End Claims" (14, 15). Petitioner argued that Miller disclosed an inclined separator mounted on a jack, demonstrating that making the inclination angle variable to suit operating conditions was a known practice (teaching claim 8). Miller's drawings depicted an angle of approximately 10-15°, falling squarely within the claimed range of "about 2 to 20 degrees" (teaching claim 12). Furthermore, Miller taught an eccentrically-located, smaller-diameter outlet pipe for solids removal, which Petitioner contended rendered the use of a smaller, eccentric vessel end obvious for the same purpose (teaching claims 14 and 15).
  • Motivation to Combine: A POSITA would be motivated to incorporate Miller's features for clear design advantages. Making the inclination angle variable provides operational flexibility to optimize separation for different fluid stream properties. More significantly, implementing a smaller-diameter cleanout end, as suggested by Miller's design, provides a strong economic incentive by reducing the size and cost of the required high-pressure access closure, which is a major expense in such vessels.
  • Expectation of Success: Success was reasonably expected because adding a variable angle mechanism and an eccentric end were known design choices for separation vessels. These were presented as straightforward engineering modifications to optimize performance and reduce manufacturing costs, with predictable and beneficial results.

• Additional Grounds: Petitioner asserted two additional grounds that mirrored the logic of the first two, but substituted the Engineering Data Book (a 1994 industry reference) for Davis as the source for teaching inclined vessels (Ground 2 in the petition) and combined the Data Book with Miller to challenge the eccentric end claims (Ground 4 in the petition).

4. Key Claim Construction Positions

• "freeboard portion": Petitioner argued that this term, which is not standard in the art, should be construed to mean the substantially gas-filled portion of the desanding vessel located above the gas/liquid interface. This construction was crucial for mapping the features of prior art separators, which have analogous gas-phase regions, onto the claim language.
• "replaceable": Petitioner contended that this term, as applied to the inlet nozzle in claims 4 and 5, refers to a component that can be removed and replaced without requiring welded modifications to the pressure vessel. This construction was important to show that Hemstock’s flanged nozzle met this limitation, as it could be unbolted and replaced.

5. Arguments Regarding Discretionary Denial

• Petitioner argued that discretionary denial under 35 U.S.C. §325(d) was inappropriate because the asserted grounds were not the same or substantially similar to the prior art considered during prosecution. The examiner's rejections had relied on a different primary reference (Lowrie), which was directed to liquid-liquid separation on a pitching marine vessel. The applicant overcame that rejection by arguing Lowrie was non-analogous. Petitioner contended its grounds, based on the inventor's own, highly analogous prior art (Hemstock) combined with references teaching the specific claimed improvements, presented a new and much stronger case for unpatentability that the examiner had not considered.

6. Relief Requested

• Petitioner requested institution of an inter partes review and cancellation of claims 1-16 of Patent 8,945,256 as unpatentable.