Potential Pressure Responses to Carbon Dioxide Sequestration by Analogy to Net Fluid Change in Reservoirs of the Southern San Joaquin Valley Basin

Geologic carbon storage entails injection of carbon dioxide (CO₂) from a stationary source into deep reservoirs. The Southern San Joaquin Valley (SJV) has a large subsurface storage capacity as indicated by over 100 years of intensive oil production. The numerous oilfields in the SJV demonstrate that the strata can trap buoyant fluids such as CO₂ for long periods of time.

Prior to substantial implementation of geologic carbon storage in any sedimentary basin, the effect of CO₂ displacement on pore-filling brine must be evaluated. One potential undesirable consequence of deep subsurface brine pressurization is changes in groundwater quality due to upward movement of brine. Another potential impact is induced seismicity.

Fluid production and pressure data in the SJV may provide a perspective on far field brine pressure changes, providing a reverse analog to CO₂ injection. To start to explore 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 each hydrocarbon pool 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. It also indicates substantial injection into moderately deep pools. These could provide a direct analog to geologic carbon storage. For instance injection to the Vedder Formation at the Kern River Field occurred at a depth appropriate for geologic carbon storage (>1 km). The injection rate was in excess of 600 thousand metric tons per year CO₂ equivalent for over a decade. This is on par with the size of the world’s current largest geologic carbon storage projects and offers a significant opportunity to develop a more detailed understanding of one potential storage unit in the SJV.

Extending the hydrocarbon pool production and injection database for the southern SJV to the 1930s will be necessary to better identify the pools for analysis in the critical early periods of anthropogenic pressure perturbation in the SJV. These may have larger fluid transfers and more pressure data available for analysis. Once the historic data set is complete, it will be used to identify specific time periods for specific pools that might provide insight into far field pressure propagation along various strata, across stratigraphy and along and through faults.
 

AAPG Search and Discovery Article #90142 © 2012 AAPG Annual Convention and Exhibition, April 22-25, 2012, Long Beach, California