Introduction

Recent media coverage has highlighted a major shortcoming in the industry of unconventional resource production, inducement of seismic events. Seismicity in certain areas of the midcontinent North America has increased drastically in the past few years. This has come to be understood as a result of pore pressure, and stress field perturbation due to water injection. Water disposal and hydraulic fracturing practices both introduce quantities of water to the subsurface which may alter the mechanical quasi-equilibrium established through geologic time. Such rapid perturbation of established stress fields can in some cases cause earthquakes. Because many of these operations are based in historically seismically quiescent regions, even magnitude 3–5 earthquakes may cause significant damage that can no longer be ignored. The public's perception, and media's coverage, of this phenomena has produced a significant discussion topic, which impedes the economies of Shale 2.0, which will seek to achieve a more efficient development of shale resources. It is clear that operators do not understand the mechanical impact of such injections, as unpredicted seismic events have been induced at an increasing rate and of increasing magnitude. Regulators in Oklahoma have taken steps to reduce the risk of operators inducing seismic events, however the lack of means to quantify induced seismicity potential has hindered deployment of effective policy. With the advent of induced seismicity, institutionalized trust is compromised once again, and this time during a serious shift in the economies of unconventional production, underpinning not just the importance of the social license to operate, but the effect such public support can have when attempting to deploy the vast infrastructure necessary to realize unconventional petroleum resources at half of the value which they were previously produced.

In order to address these concerns, a workflow is proposed, to combine advanced modeling techniques, with large geologically and geophysically constrained datasets. This workflow is applied to investigate the relationship between complex regional fault systems, and their collective impact on stress fields in a region. The outputs of this modeling workflow can be combined into proxies, and used to investigate areas of the model with stress fields more likely to be perturbed through high-volume injections. Plotting these proxies on a map provides a tool that is simple to interpret, and which leverages large amounts of data and advanced modeling. This simple tool can be utilized by geoscientists, regulators, and the general public.

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