In this study, we investigate formation damage due to acidization and water injection tests into the naturally fractured carbonate Middle Duperow Formation at Kevin Dome, Montana, potentially diminishing the chance of a future successful Geological Carbon Sequestration (GCS) project. Multiple well-test analytical models, correlated with core description and lithology data, are used to determine flow behavior and communication between the water injection interval and surrounding formations. An improved three-dimensional (3D) geologic model with dual-continuum matrix and fracture properties is constructed based on most recent seismic, core, and water sample measurements. Brine injection is simulated to verify the interpretation from the analytical models, followed by CO₂ injection simulation. Geochemical calculations are performed to understand the in-situ processes that led to formation damage. Our findings suggest: (1) there are two possible scenarios that could lead to a positive total effective skin factor and permeability decline: partial penetration and formation damage; (2) analytical models indicate a positive total skin factor, contradicting results of a previous study suggesting that the well was mildly stimulated; (3) numerical simulation supports the formation damage hypothesis by matching the pressure buildup observed during the latter two brine injection tests; (4) several mechanical and chemical processes may have occurred during injection to clog the matrix/fracture system: anhydrite fines migration and/or calcite precipitation. We then make preventative suggestions for future GCS projects into carbonate reservoirs and remediation recommendations for GCS operation at the Kevin Dome.

在这项研究中，我们调查了由于酸化和注水测试造成的地层损害，该测试是在蒙大拿州凯文巨蛋的天然裂缝性碳酸盐中杜珀罗组中进行的，这有可能减少将来成功进行地质碳封存（GCS）项目的机会。与岩心描述和岩性数据相关联的多个试井分析模型用于确定注水层段与周围地层之间的流动行为和连通性。基于最新的地震，岩心和水样测量结果，构建了具有双连续矩阵和裂缝特性的改进的三维（3D）地质模型。模拟盐水注入以验证分析模型的解释，然后是CO ₂注射模拟。进行地球化学计算以了解导致地层破坏的原位过程。我们的发现表明：（1）有两种可能导致总有效表皮因子和渗透率下降的正数：部分渗透和地层破坏；（2）分析模型表明总皮肤因子为正，与先前的研究结果相反，表明该井受到了轻微的刺激；（3）数值模拟通过匹配后两次盐水注入试验中观察到的压力积累来支持地层破坏假说；（4）在注入过程中可能发生了几种机械和化学过程，从而堵塞了基质/裂缝系统：硬石膏的细粉迁移和/或方解石沉淀。