The Integrity of Idle and Abandoned Wells in California

Abstract

Abstract One of the critical challenges of California's 2045 carbon neutrality plans is the sources of greenhouse gas emissions (GHG) and the states' methods to improve emissions. This work provides insight into plugged wells, idle wells, and their potential for emission of methane and emission interferences these wells have with the states' carbon-neutral plans. Alternative solutions exist to abandon certain idle wells. Repurposing wells can generate revenue for oil and gas operators. By repurposing wells, operators can significantly reduce the cost of decommissioning the wells, highlighting the need for risk assessment in wells with the potential to leak methane. By studying over 330 randomly selected plugged and abandoned wells throughout California, this study demonstrates how the condition of idle well emission needs further investigation. The potential benefit of confirming if plugged and abandoned wells are leaking methane into the atmosphere is assessed while the methods for characterizing wellbores are identified. Based on California's carbon neutrality goals, assessing the potential of a well for leaking methane into the atmosphere is dependent on the well's integrity changes, improper plugging, and geological shifts, including a detailed approach to the evaluation of characterizing wells based on the potential for cracks in the wellbore cement, inadequate cementation, or likelihood of fluid release through tectonically induced pathways based on wellbore diagrams and the cement class. This study can be of benefit to regulatory agencies and operators for improved development towards GHG emission reduction.