Downhole pressure and chemical monitoring for CO2 and brine leak detection in aquifers above a CO2 storage reservoir

摘要

We assess the effectiveness of downhole monitoring of pressure and chemistry for detecting CO2 and brine leakage into underground sources of drinking water (USDW) overlying a geologic CO2 storage (GCS) reservoir. This assessment uses synthetic data sets generated in an uncertainty quantification (UQ) model framework. This framework combines the results of three model types: (1) a model of a hypothetical, 50-yr, 5-MT/yr GCS operation in the Vedder Fm. at the Kimberlina site in the southern San Joaquin Basin in California, USA, (2) models of CO2/brine leakage in legacy wells into overlying aquifers, and (3) models of CO2/brine plume migration in those aquifers. Leakage into overlying aquifers causes changes in pressure, CO2 saturation, and total dissolved solids (TDS), the latter being related to the solubility and speciation of CO2. This study captures the influence of leakage depth along the legacy well, regional groundwater flow, and aquifer heterogeneity on leak detection using downhole pressure and TDS monitoring.