Application of Oilfield Geomechanics Techniques to Geologic Carbon Capture, Utilization, and Storage (CCUS) Projects

Abstract

Abstract With increasing industry and government attention directed toward climate change mitigation, CO2 injection wells are expected to play a vital role in America’s emerging energy infrastructure and to make up an ever-increasing share of commercial wellbore geoscience activities. The Environmental Protection Agency (EPA) assigns CO2 injection wells to a category distinct from oil and gas wells, asserts regulatory primacy, and imposes a specific set of regulatory guidelines that drive well planning procedures for what it defines as Class VI injectors. These permitting requirements for a Class VI injector are notably stricter than for a traditional hydrocarbon producing well, which also drives an expectation for greater precision in quantifying several geologic parameters during well planning. For geomechanics teams, this presents a valuable opportunity to develop customized models to optimize drilling and injection procedures, following in the footsteps of what has already been accomplished with horizontal drilling and hydraulic fracturing in the onshore unconventional space over the past two decades. In this paper, we examine the application of oilfield geomechanics techniques, including pore pressure prediction, rock strength estimation, and wellbore stability analysis to assist in drilling and completion of CCUS wells. We walk through the workflow to build a robust 1-D geomechanical model, calibrated to available offset data utilizing field and wellbore scale geomechanical modeling platforms. Next, we identify best practices for drilling and completing CO2 injectors. Finally, we apply the geomechanical modeling methodology to CCUS wells, focusing on four key operational risks that are exacerbated compared to similarly situated oil and gas wells: overpressure, borehole breakout, fault reactivation, and stress changes with depletion and injection. We conclude by considering future research opportunities in this field.