Injection wells have been used for decades in California to assist in oil production – to increase oil recovery and safely dispose of water produced with oil and gas.
When oil is pumped from underground, it comes out co-mingled with water – called “produced water.” That water is either treated and used for enhanced oil recovery (EOR) or disposed of by injecting it back underground. A small portion is treated and provided for agricultural purposes, providing a critical source of irrigation water during the drought. This water must meet specific water quality standards and permit requirements dictated by local regulators.
Every barrel of oil produced in California also produces an average of 15 barrels of water, or 130 billion gallons of water per year.
There are approximately 50,000 injection wells in California. 48,200 are used for enhanced oil recovery and 1,800 are water disposal wells. The Underground Injection Control (UIC) program regulates the operation of injection wells, providing both federal and state agency oversight:
- U.S. Environmental Protection Agency
- California Division of Oil, Gas & Geothermal Resources (DOGGR)
- State Water Resources Control Board (SWRCB)
The US EPA periodically reviews the state’s UIC program. As a result of an audit, and in light of the drought, DOGGR and the SWRCB are conducting a comprehensive review to ensure injection wells in California are operating safely and in compliance with all applicable laws and regulations. Regulators are systematically evaluating a select group of permitted injection wells to determine if they are injecting into aquifers that could be potential future sources of public water supplies based on their reported salinity.
The review will be an exhaustive process with measurable milestones and will be closely monitored by the EPA. California’s oil producers support this review and have been working collaboratively with the regulators to inventory all wells and provide the necessary data.
To date, no contamination of water used for public water supply systems in the state’s ongoing analysis.