Prior to substantial implementation of GCS in any sedimentary basin, effect of CO2 displacement on pore-filling brine must be evaluated. Potential consequences of deep subsurface brine pressurization include changes in groundwater quality due to upward brine movement and induced seismicity.
Fluid and pressure data in the SJV may provide a perspective on brine pressure changes, providing a reverse analog to CO2 injection. Exploring this opportunity, a database of production and injection volumes from the California Division of Oil, Gas and Geothermal Resources (DOGGR) was constructed and analyzed to determine yearly net production and injection values from 1977 to 2010 for hydrocarbon pools in the SJV.
The data show numerous instances of substantial removal or injection of fluids, with apparent fluid transfers both between and along strata within fields. Substantial injection into moderately deep pools could provide a direct analog to GCS. For instance, injection to the Vedder Formation at the Kern River Field occurred at a depth appropriate for GCS (>1 km). For over a decade, the injection rate exceeded 600 thousand metric tons per year CO2 equivalent. This magnitude matches the world’s current largest GCS projects and offers an opportunity to further develop our understanding of potential storage units in the SJV.
Extending the hydrocarbon database for the southern SJV to the 1930s will better identify pools for analysis in the critical early periods of anthropogenic pressure perturbation. Once complete, the historic data will be used to identify time periods for specific pools that might provide insight into far field pressure propagation along and across various strata and faults.