The following is a fact sheet for our “Case Study on Injection Well Projects in Monterey and Fresno Counties”. This case study examines failures in the California Department of Conservation, Division of Oil, Gas, and Geothermal Resources’ (DOGGR) oversight of Class II oil & gas injection wells, based on DOGGR’s own project and well files. Research from the California Council on Science and Technology’s 2015 report and other sources support the conclusion that failures in the Class II Underground Injection Control (UIC) Program risks contamination of neighboring aquifers, including Underground Sources of Drinking Water (USDWs).
Summary of Key Points:
- Across California, there are tens of thousands of wastewater disposal and enhanced oil recovery wells. Despite DOGGR’s admission that many of these wells lack the legally-required data and documentation to ensure safe injection, they continue to operate.
- DOGGR’s “project-by-project review” is a process for DOGGR to address the large number of well projects that lack the critical and legally-required data for each Area of Review (AOR). The AOR is a federally-defined areal review of all water resources, oil and gas wells, and geologic zones within a one-quarter mile radius of an oil and gas injection project.
- Fluids injected underground contain a wide range of contaminants, including BTEX compounds, heavy metals and other toxic compounds. When those fluids are not properly managed, migration out of the intended injection zone may occur, potentially contaminating surrounding aquifers. Specifically, overpressurization of wastewater injection zones can lead to the contamination of USDWs.
- This study reviews DOGGR’s own data and documentation for a project in the San Ardo field, within the Salinas Valley Groundwater Basin, that has continued to inject waste fluids despite repeated technical failures, evidence of fluid migration out of the intended geologic zone, and other clear contamination risks.
- The records show that for decades, and continuing through the present day, DOGGR has allowed the injection of waste fluids into areas where there is excessive hydrostatic pressure, i.e. local pressure resistance and volumetric capacity in the injection zone is exceeded by the volume and pressure of waste fluids injected. The industry and DOGGR have repeatedly sought short-term fixes for continued injection of waste fluids, including drilling new disposal wells in already overpressured zones.
- Specific issues include well pressure testing failures and data validation concerns. Many wells found in violation were allowed to continue waste fluid injections.
- These shallow injection zones known as the Lombardi sands and the Aurignac sands consistently experience overpressurization issues, leading to potential fluid migration.
- In mid-2015, DOGGR sent a letter notifying the operator, Chevron, that these overpressured zones within the San Ardo field would need aquifer exemptions for wastewater disposal wells to continue to operate. Each of these zones, some as shallow as 2000 feet, have yet to receive an aquifer exemption. These injection operations continue today.
- Similar programmatic failures allowed injection projects to continue in Fresno County. Injection well projects in the city of Riverdale and Raisin City, located within the boundaries of Fresno’s Sole Source Aquifer, were initially permitted and have continued operating despite lacking legally-required geologic and engineering data and documentation.
These case studies demonstrate DOGGR’s continued failure to properly oversee industry injection projects. Such oversight is particularly important where California’s vital water resources are at risk of contamination.