Shale gas has recently emerged as a major energy source in the United States. Shale are fine-grained rocks of which matrix permeability is on the order of nano-darcies, which means that the key to economic production of gas is stimulation of reservoirs by hydraulic fracturing. It is of great importance to diagnose characteristics of created fracture geometry such as fracture height, thickness, azimuth, etc., to control and optimize fracturing process. Practically, two techniques are available to monitor fracture geometry created by hydraulic fracturing inclusive microseisimic and tiltmeter monitoring techniques. In this study the focus was on monitoring techniques using tiltmeter instruments, especially surface tiltmeters. This work presents a numerical code to determine ground deformation due to a pressurized penny-shaped crack embedded in semi-infinite space (what is faced in hydraulic fracturing). Currently, there are no analytical solutions available for a pressurized crack in semi-infinite space. Therefore, there should be a numerical technique to solve governing equations in these cases. Moreover, a calculation scheme is required to perform into the code to consider general shapes of cracks like noncircular or non-elliptic cracks with nonplanar surface. In this thesis work, the MATLAB software was used to develop a numerical analysis code. Next, analytical solutions for infinite space and the numerical code was examined to find out the difference of calculation results between them, in case the effect of ground surface on deformation addressed, which is justify the recommended approach for a crack in a semi-infinite space. The results demonstrated that the developed numerical code result of the prospective work will accurately calculate the surface deformation caused by hydraulic fracturing, so that it can be an advantageous tool to interpret data gathered by surface tiltmeters in order to estimate fracture geometry. Keywords: Numerical code, Penny-Shaped crack, Semi-infinite space, Surface deformation, Tiltmeter
July 28th, 2016
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