Date of Graduation
Statler College of Engineering and Mineral Resources
Mechanical and Aerospace Engineering
Derek R Johnson
Andrew C Nix
Gregory J Thompson
The US natural gas extraction industry has grown by 25% over the past decade. This has encouraged the well completion industry to utilize produced natural gas to meet power demands previously obtained with diesel fuel. The major "prime-movers" of diesel fuel consumption are over-the-road (OTR) trucks, high horsepower drilling, and high horsepower hydraulic fracturing engines. The US Department of Energy (DOE) recently granted West Virginia University (WVU) funding, under agreement DE-FE0013689, to "Assess Fugitive Methane Emissions Impact Using Natural Gas Engines in Unconventional Resource Development." As part of the funding, WVU was tasked with creating engine activity cycles representative of the prime-movers' in-use operation.;In-use data were collected from the major prime-movers in the Marcellus shale play region. Cycles were created to replicate the engine speed and load activity. Cycle creation was achieved by applying a Markov chain Monte Carlo (MCMC) technique. The Markov chain utilized second-by-second concatenation and a transition probability matrix based on the collected data distribution. This approach allowed for a large number of cycles to be created. Comparing cycles to collected data employed a Performance Value (PV), which accounted for data statistics and distribution. Populations of 10,000 cycles were created for each of the major prime-movers.;Optimization of cycles was achieved with the use of a genetic algorithm (GA). The GA used the genetic operators of crossover and mutation, had a population of 100 cycles, and lifespan of 50 generations. The GA was executed for of the major prime-mover cycles: OTR trucks, drilling, and hydraulic fracturing improving their PVs by 18%, 62%, and 65%, respectively compared to the best individual of the initial population. The final cycles were exercised on a Cummins ISLG natural gas engine mounted to an 800 horsepower dynamometer for verification of regression criteria. The drilling and hydraulic fracturing cycles met all regression criteria defined by the CFR however, the OTR cycle did not. A Savitsky-Golay (SG) smoothing technique was applied to the cycle, resulting in a 1.25% increase in the PV. The smooth OTR cycle met all regression criteria. This completed the definition of all three prime-mover cycles.
Heltzel, Robert S., "Development of Engine Activity Cycles for the Prime-Movers of Unconventional Well Completion" (2016). Graduate Theses, Dissertations, and Problem Reports. 5790.