PTAB

IPR2025-01424

Liberty Energy Services LLC v. US Well Services LLC

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Petition
petition

1. Case Identification

2. Patent Overview

  • Title: Mobile Grid Assembly for Hydraulic Fracturing System
  • Brief Description: The ’801 patent relates to a hydraulic fracturing system using a mobile grid assembly to power electric fracturing pumps. The system features multiple mobile power units (MPUs) linked by a common bus interconnect to enable load sharing and improve operational efficiency in space-limited environments.

3. Grounds for Unpatentability

Ground 1: Obviousness over Reckels and IEEE Red Book - Claims 1-4, 6, 8-10, 12-14, 16, 18, and 19 are obvious over Reckels in view of IEEE Red Book.

  • Prior Art Relied Upon: Reckels (WO 2018/071738) and IEEE Red Book (ANSI/IEEE Std 141-1986).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Reckels discloses a mobile electric fracturing system with separate power generation trailers and pump trailers. Reckels explicitly suggests its gas turbines and pumps can be connected to a "common bus bar" to allow generators to run at different loads for load sharing. However, Reckels does not provide detailed implementation guidance. Petitioner asserted that the IEEE Red Book, a well-known professional standard for industrial electric power distribution, remedies this by teaching main-tie-main systems where multiple power sources and loads are linked via a tie bus or interconnecting cable, which serves the same function as Reckels’ "common bus bar" to provide load sharing and redundancy.
    • Motivation to Combine (for §103 grounds): A POSITA, when implementing Reckels’ general suggestion of a common bus bar, would naturally consult a standard industry reference like the IEEE Red Book for detailed design principles. The motivation was to achieve the well-known benefits of such systems—improved efficiency, operational flexibility, and redundancy—by applying a standard, documented power distribution architecture to Reckels' mobile fracturing application.
    • Expectation of Success (for §103 grounds): A POSITA would have a high expectation of success, as the combination involved applying a predictable, standard electrical engineering design to a known type of industrial system to achieve its expected benefits.

Ground 2: Obviousness over Reckels, IEEE Red Book, Coli, and Solar Turbines - Claims 5 and 15 are obvious over Reckels, IEEE Red Book, Coli, and Solar Turbines.

  • Prior Art Relied Upon: Reckels (WO 2018/071738), IEEE Red Book (ANSI/IEEE Std 141-1986), Coli (Application # 2012/0255734), and Solar Turbines (a 2016 product guide).
  • Core Argument for this Ground:
    • Prior Art Mapping: This ground builds on the system of Ground 1 by providing specific, real-world component examples to meet limitations related to generator power output. Claim 5 requires a system with multiple generators whose individual power outputs are less than that of a larger, isolated single generator. Petitioner pointed to Coli for teaching typical fracturing pumps (e.g., 2,500 hp) and a large, isolated mobile generator (the 31 MW TM2500+). Petitioner then used Solar Turbines to show a smaller, commonly used generator (the 5.7 MW Taurus 60) that would be suitable for the multi-generator system of Reckels. The combination of these references allegedly discloses all elements of claim 5.
    • Motivation to Combine (for §103 grounds): A POSITA tasked with building the conceptual system from Reckels and IEEE Red Book would be motivated to consult references like Coli and Solar Turbines to select specific, commercially-available, and appropriately-sized pumps and generators. This represents a routine and necessary step in the engineering design process to move from a system schematic to a practical, working implementation.

Ground 3: Obviousness over Reckels, IEEE Red Book, and Oehring178 - Claims 7 and 17 are obvious over Reckels, IEEE Red Book, and Oehring178.

  • Prior Art Relied Upon: Reckels (WO 2018/071738), IEEE Red Book (ANSI/IEEE Std 141-1986), and Oehring178 (Application # 2017/0030178).

  • Core Argument for this Ground:

    • Prior Art Mapping: This ground addresses limitations requiring a Variable Frequency Drive (VFD) and a Motor Control Center (MCC) on the external mobile pump units. Reckels disclosed VFDs but located them in an "electric room" on the main power generation trailer. Oehring178, however, explicitly teaches placing both VFDs and MCCs directly on the same mobile trailer as the fracturing pumps they control. Petitioner argued the combination of these references renders the claimed configuration obvious.
    • Motivation to Combine (for §103 grounds): A POSITA would combine these teachings to create a more modular and efficient system. Placing motor controls on the same trailer as the motors is a well-known design choice. Modifying Reckels by moving the VFDs from the power trailer to the pump trailers, as taught by Oehring178, would be a simple substitution of one known element location for another to obtain the predictable result of a more integrated pump unit.

  • Additional Grounds: Petitioner asserted an additional obviousness challenge (Ground 4) for claims 11 and 20 based on the combination of Reckels, IEEE Red Book, Oehring178, and Kumar, arguing Kumar teaches using isolation transformers on the pump trailers to filter harmful harmonics generated by the VFDs.

4. Relief Requested

  • Petitioner requests institution of an inter partes review and cancellation of claims 1-20 of Patent 11,211,801 as unpatentable.