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 describes a system and method for removing particulates, such as sand, from multiphase fluid streams produced by oil and gas wells. The invention centers on an elongated, cylindrical vessel that is inclined from the horizontal to use gravity to separate entrained solids and liquids from a gas stream.

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 argued that Hemstock disclosed a desanding apparatus nearly identical to that of the ’256 patent, including an elongated vessel, a fluid inlet and outlet, and a design that slows fluid velocity to allow particulates to fall into a "belly portion." The primary difference, Petitioner asserted, was that Hemstock’s vessel is horizontal, whereas the challenged claims require the vessel to be inclined at a non-zero angle. Davis, a foundational article on sedimentation, was cited for its explicit teaching that inclining settling vessels or channels significantly enhances the speed and efficiency of solid-liquid separation.
  • Motivation to Combine: A POSITA would combine the teachings of Hemstock and Davis to improve the performance of Hemstock’s desander. Petitioner contended that a POSITA would be motivated to incline the Hemstock vessel to achieve more rapid sand settling, thereby preventing the re-entrainment of solid particulates into the fluid stream leaving the outlet. This desire to improve particulate settling efficiency was presented as a direct and implicit motivation to apply the well-known principle taught by Davis.
  • Expectation of Success: Petitioner argued that a POSITA would have had a reasonable expectation of success. Inclining vessels to improve gravitational separation was a well-established and predictable technique in the art. Applying this known principle to Hemstock’s existing separator would be expected to yield the desired improvement in separation efficiency without any negative or unforeseen consequences.

Ground 2: Obviousness over Hemstock and the Data Book - Claims 1-16 are obvious over Hemstock in view of the Data Book.

• Prior Art Relied Upon: Hemstock (Patent 6,983,852) and the Data Book (Engineering Data Book, Gas Processors Suppliers Association, 1994).
• Core Argument for this Ground:
  • Prior Art Mapping: This ground presented a similar argument to Ground 1, with Hemstock providing the foundational horizontal desander. The key difference was the substitution of the Data Book for Davis. The Data Book, a standard industry reference, was cited for its teaching that "slug catchers"—separators designed to handle multiphase flow—are often inclined from one to ten degrees to absorb fluctuating liquid flow and improve separation.
  • Motivation to Combine: The motivation to combine was based on improving the Hemstock device's ability to handle unstable multiphase flow, particularly "slugs" of liquid, which Hemstock itself acknowledges are common. A POSITA would have recognized that inclining the vessel, as taught by the Data Book for slug catchers, would improve liquid-vapor separation efficiency and make the device more robust. The Data Book also provided specific, conventional inclination angles (1-10 degrees), directly suggesting the modification for claims 8 and 12.
  • Expectation of Success: As the Data Book is an authoritative engineering guide, a POSITA would have had a high degree of confidence that applying its standard design principles for inclined separators to Hemstock's functionally similar desander would be successful and effective.

Grounds 3 & 4: Obviousness with the Addition of Miller - Claims 14 and 15 are obvious over Hemstock, Miller, and either Davis (Ground 3) or the Data Book (Ground 4).

• Prior Art Relied Upon: Hemstock (Patent 6,983,852), Miller (Patent 1,458,234), and either Davis or the Data Book.
• Core Argument for this Ground:
  • Prior Art Mapping: These grounds built upon the combinations in Grounds 1 and 2 to address claims 14 and 15, which require the vessel to have a smaller-diameter, eccentric end downstream of the fluid outlet. Miller, a 1923 patent, was introduced for its teaching of a separation vessel with an eccentrically located, smaller-diameter outlet pipe at its lower end to facilitate the removal of collected solids.
  • Motivation to Combine: Petitioner argued a POSITA would be motivated to add Miller’s eccentric end design to the inclined Hemstock vessel for clear economic and functional reasons. Quick-release closures for cleanout ports (as taught in Hemstock) are expensive, and their cost increases with size. Reducing the vessel diameter at the cleanout end, as taught by Miller, would reduce fabrication costs. Furthermore, placing this smaller end eccentrically at the lowest point of the inclined vessel would naturally improve the efficiency of removing accumulated solids.
  • Expectation of Success: This modification was presented as a straightforward mechanical combination of known elements for predictable purposes. A POSITA would have reasonably expected that adding a feature designed for cost reduction and improved solids removal (from Miller) to a separator vessel (the inclined Hemstock) would function as intended.

4. Key Claim Construction Positions

• "freeboard portion": Petitioner argued this term, not routinely used in the art, refers to the substantially gas-filled portion of the desanding vessel above the gas/liquid interface. This construction was based on its usage in the ’256 patent specification.
• "replaceable": As used in claims 4 and 5 regarding the inlet nozzle, Petitioner proposed this term refers to the capacity to be removed without requiring welded modifications to the main pressure vessel. This construction was argued to be consistent with the specification and common usage in the art for ease of maintenance.

5. Arguments Regarding Discretionary Denial

• Petitioner argued that the asserted grounds were not the same or substantially similar to those previously presented to the USPTO during prosecution, making discretionary denial under §325(d) inappropriate. It was noted that the examiner previously relied on the Lowrie patent, which the applicant successfully distinguished as not being a desanding system and not teaching an inclined vessel. Petitioner contended that the newly cited art—specifically Davis, the Data Book, and Miller—remedied these deficiencies by directly teaching the key missing element of inclining a vessel to improve particulate separation.

6. Relief Requested

• Petitioner requested institution of an inter partes review and cancellation of all challenged claims (1-16) of the ’256 patent as unpatentable.