Basin-Scale Reservoir Management Strategies for CO2 Storage

Abstract Injection of CO2 into geologic formation creates a buildup of pressure within the storage formation(s). Proximately located injection and storage projects in the same basin/formation may induce significant buildup in pressure and impose pressure interference effects, impacting injectivity, reducing available storage resources, and increasing pressure-induced risks. This research employed basin-scale numerical modeling to analyze how pressure fronts in the subsurface evolve when CO2 is injected from multiple projects located in proximity. Simulation of CO2 injection occurred under different conditions: 1) injection using multiple wells into a single storage formation (baseline), 2) injection using multiple wells into multiple, stacked formations, and 3) varying injection well spacing. TOUGH3-ECO2M was used to construct a site geologic model and simulate CO2 injection over different operational and design scenarios. Key findings highlight that while CO2 plumes are relatively localized (2–3 km in radius), pressure buildup propagates extensively, reaching tens to hundreds of kilometers and therefore could significantly impact storage prospects for operators planning to inject CO2 far from the project site. Pressure interference between adjacent wells in a single formation dramatically increases pressure buildup (by up to a factor of two) compared to an uninterrupted single-well scenario. However, injecting CO2 into a stacked sequence of formations was shown to be effective towards reducing pressure buildup by over 40 percent (at the injection well) and pressure interference amongst wells by upwards of 54 percent when compared to injecting a similar volume of CO2 into a single formation. Distribution the injection volume vertically across different intervals lowers the risk of exceeding potential fracture pressure thresholds, allows for more efficient use of basin-wide storage resources, and may reduce the areal extent of the Area of Review (AoR). This work aims to provide a comprehensive, detailed synthesis of basin-scale CO2 storage dynamics via evaluation of the fundamental principles of pressure buildup and interference, exploring the efficacy of different pressure management strategies (well spacing and stacked injection), and providing context for critical implications related to project design, basin resource management, and regulatory coordination.