Hybrid Fracturing Pump Drive With Torque-Assisted Gas Engine Shifting
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Solution Overview
Problem
Hydraulic fracturing operations face challenges with noise and particulate emissions from diesel-powered fleets, and reciprocating gas engines are not responsive to variable loads, making them impractical for use in oilfield pumping due to fuel quality issues and regulatory compliance.
Innovation Solution
A hybrid system combining a reciprocating gas engine with a dual electric machine and magnetic drive, which includes a gas preprocessing unit to condition field gas for use as fuel, and a dual electric machine to provide torque assistance and maintain engine speed, allowing for variable speed operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If diesel-powered fleets are used for hydraulic fracturing operations, then pumping capacity and power availability are sufficient, but noise and particulate emissions increase causing regulatory and community issues
Solution Approach 1:
The patent combines a reciprocating gas engine with an electric motor into a hybrid power system. The gas engine provides base power with lower emissions, while the electric motor supplements power during high-demand periods, achieving both reduced harmful factors and maintained power availability.
Solution Approach 2:
The electric machine in the hybrid system serves multiple functions: it acts as a motor to supplement power when needed, and can also function as a generator to recover energy during braking or load reduction, providing versatile power management while reducing overall emissions.
2Object-generated harmful factors
If reciprocating gas engines are used for oilfield pumping, then emissions are reduced compared to diesel, but responsiveness to variable loads and fuel quality issues make them impractical
Solution Approach 1:
The hybrid system merges the emissions advantages of gas engines with the load-responsive capabilities of electric motors. The electric motor provides immediate torque response to variable loads, compensating for the gas engine's slower response, while the gas engine maintains lower emissions during steady-state operation.
Solution Approach 2:
The electric motor acts as an intermediary between the gas engine and the pump load. It buffers the load variations, allowing the gas engine to operate more steadily while still meeting peak power demands, thus improving overall system adaptability without sacrificing emissions benefits.
3Object-affected harmful factors
If VFD electric motors are used to reduce noise, then noise levels decrease, but system complexity and setup time increase making them impractical in the field
Solution Approach 1:
The hybrid system combines the gas engine's mechanical drive capability with electric motor assistance, achieving noise reduction through the quieter operation of the electric motor during variable load conditions, without requiring complex VFD control systems.
Solution Approach 2:
The hybrid system uses the electric machine's inherent ability to provide torque at variable speeds without requiring external power lines or complex control infrastructure. The system serves itself by using the electric motor's natural characteristics to reduce noise during operation.
4Reliability
If gas preprocessing units are added to condition field gas, then fuel quality improves enabling gas engine operation, but device complexity increases
Solution Approach 1:
The gas preprocessing unit performs fuel conditioning in advance of engine operation, removing contaminants and adjusting composition to meet engine requirements. This preliminary treatment ensures reliable operation while keeping the preprocessing functions integrated and compact to minimize overall system complexity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The hybrid system improves power transfer and responsiveness to variable loads, reducing noise and emissions, and enables the use of field gas as fuel, making it suitable for hydraulic fracturing operations.
Implementation Method 1
The driveline may include a magnetic drive
Implementation Method 2
A dual electric machine is operably mounted at a position selected from a group consisting of: (1) at the first end of the reciprocating gas engine, and (2) within the driveline
Implementation Method 3
a reciprocating gas engine having a first end and a second end. The reciprocating gas engine has an operating system that seeks to establish a constant operating speed
Data Source
AI summary
Oilfield pumping systems are improved by the incorporation of a reciprocating gas engine having a mode of operation that seeks to maintain a constant engine speed or rotational velocity. A driveline including a transmission with shiftable gears connects the reciprocating gas engine with a hydraulic pump configured for use in oilfield hydraulic fracturing operations. A control system is configured with programmatic instructions for operating a dual electric machine that alters torque emanating from the reciprocating gas engine to facilitate upshifting of gears in the transmission. This may be done by preloading the reciprocating gas engine with reverse or negative torque operating against that emanating from the reciprocating gas engine prior to the upshifting of gears, and/or by providing positive torque to assist that of the reciprocating gas engine after the upshifting of gears.