Understanding the risk of induced earthquakes associated with oil and gas development and procedures for risk mitigation [electronic resource]

In this thesis, I investigate three main topics. First, the developing issue of the risk associated with earthquakes triggered by oil and gas operations, including the characterization of the injection site, the assessment of triggered earthquake risk, and a case study in South Texas where I apply our suggested practices. Second, I examine the mechanisms of deformation at a heavy oil reservoir undergoing cyclic steam stimulation. Finally, I explore the possibility of tectonic tremor in the aftermath of the 2010 M 8.8 Maule, Chile earthquake using a temporary seismic array. The chapters within this thesis demonstrate the importance of multi-disciplinary studies in determining where and how subsurface failure might occur. Starting in 2009, the central and eastern United States has seen an unprecedented increase in earthquakes. A region once known for having relatively low levels of earthquake activity has now exceeded the earthquake rate of California. These earthquakes are suspected to be the result of oil and gas operations. Couple this with a lack of sufficient regulations to manage the issue and a lack of comprehensive protocols and guidelines, and we are left with a human-induced issue that has the potential to cause damage in regions with significant exposure. Part of this dissertation builds off previously published regulations and guidelines that seek to mitigate the risk of these triggered earthquakes, but often do not include important information. In response to this, I provide a comprehensive outline of how a site could be characterized in order to fully inform the potential for triggered earthquakes and offer suggestions for injection and seismic monitoring and reporting to increase the ability to correlate potentially triggered earthquakes with operational practices, ultimately informing the risk in a region. In addition, I developed a risk assessment procedure that includes the earthquake hazard, operational factors, exposure and vulnerability, and risk-tolerance. In addition, I offer suggestions for the utilization of a modified traffic light system that will allow operators and regulators to mitigate triggered earthquake risk in a proactive manner. These guidelines are then applied to the Eagle Ford Shale operational area in South Texas as a case study and example of how publically available data can inform triggered earthquake risk in an operational setting. In addition to triggered earthquake risk and mitigation, I performed a multidisciplinary study to explore possible mechanisms leading to the observed deformation as the result of steam injection at a heavy oil production pad. The deformation was due to substantial pore pressure increases following the first instance of steam injection at the site. This reservoir is of particular interest because of its unique data set and physical properties. Here, we present a review of the possible deformation mechanisms. We performed a examined the correlation between the observed microseismic events, surface deformation, steam injection and modeled pore pressure changes in the reservoir (Maharromov, 2016) as determined using the tilt observations. We concluded that the microseismic events outside the reservoir likely follow theory introduced in Segall (1989), which describes stress changes outside a reservoir due to pore pressure changes. Finally, I explored the possibility of tectonic tremor occurring in the aftermath of the 2010 M 8.8 Maule, Chile earthquake using the temporary Chile RAMP array. I applied a hypocenter determination method developed by Dr. Satoshi Ide and found the aftershocks to be too numerous, even months after the mainshock, to successfully apply the technique.

Keywords: Geophysics.
Advisor: Zoback Mark D. primary advisor. Thesis advisor
Beroza Gregory C. (Gregory Christian) advisor. Thesis advisor
Segall Paul