Semester

Summer

Date of Graduation

2021

Document Type

Thesis

Degree Type

MS

College

Statler College of Engineering and Mineral Resources

Department

Mechanical and Aerospace Engineering

Committee Chair

Derek Johnson

Committee Member

Andrew Nix

Committee Member

Scott Wayne

Abstract

The United States (U.S.) has experienced a natural gas “boom” due to the development of unconventional shale plays, but well development is energy intensive. Operations use electric drilling rigs typically powered by either three high-horsepower diesel engines (HHPDE) or three dedicated natural gas engines (DNGE) and associated generators. From a first law analysis, HHPDEs peak at 42% efficiency at full load, while DNGE peak at about 30%. Most of the fuel energy is lost as heat rejected by the exhaust and radiators. Concurrently, during cold seasons rigs utilize boilers to provide steam throughout the rig to prevent freezing and provide comfort. The U.S. Department of Energy (DOE) and the National Energy Technology Laboratory (NETL) recently granted West Virginia University (WVU) funding, under agreement DE-FE0024297, to “develop and validate new knowledge and technology to improve recovery efficiency and minimize environmental implications of unconventional resource development.” As part of the funding, WVU was tasked with auditing the energy consumption during the horizontal drilling of an unconventional well, processing the data, and assessing methods to reduce fossil fuel consumption and associated emissions during the development phase. My research analysis focused on a combined heat power (CHP) approach as a means to improve the utilization factor (UF) of fossil energy consumed during development. Engine activity, boiler fuel consumption, and exhaust gas temperatures were recorded during winter drilling of an entire well in the Marcellus shale. Four characteristic activity cycles were extracted from recorded engine and boiler activity to represent four energy consumption scenarios. Exhaust and jacket water heat exchangers (E-HEX, JW-HEX) were designed and simulated, and results were analyzed in 0-D models for the four case scenarios. A 584-kWh hybrid energy management system (HEMS) was also designed and simulated into the model as another method to reduce fossil fuel energy consumption during well development. HHPDE UF improved on average from 35.7% to 55.7% if only E-HEXs were used and improved to 72.7% if JW-HEXs were also used. DNGEs were less efficient than HHPDE; therefore, more waste heat was available and at a higher quality (temperature). DNGE average UF increased from 19.0% to 34.9% using E-HEX only. HEMS utilization improved UF up to an average of 76.9% and 39.1% for HHPDE CHP and DNGE CHP systems, respectively

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