Plug and Abandonment Challenges in Tectonically Active California

Abstract California's oil and gas industry exists in a geologically complicated and seismically active region. Southern and Central California are subjected to substantial stresses imposed by tectonic forces. Seismic events due to these forces can cause adverse effects on subsurface wells, including casing distortion and cement failure of the wellbore. Given the history of the California oil and gas industry, the number of poorly abandoned, idle, and orphaned wells that need attention is huge. It is clear that well abandonment is an issue that needs genuine attention, and it must be addressed for the protection of the environment. This paper combines examples from the cementing literature, regulatory frameworks, and case histories to focus on the insights gained from the damages caused to the wellbore and infrastructure. It also discusses the role of advanced materials, like ductile cement for squeeze cementing, in safeguarding the integrity of the abandoned wells. It also calls for cooperation with regulatory agencies to adopt policies to help promote monitoring of well damage after major earthquakes. Earthquakes like the 1933 Long Beach Earthquake and the 1983 Coalinga Earthquake demonstrate the potential impact of seismic activities on oilfield infrastructure. These seismic events can potentially lead to compromised wellbore integrity, creating long-term challenges for plug and abandonment operations. By examining selected historical cases, this paper seeks to offer some solutions for such wells and discuss the technologies that can help with the solutions. We conducted a detailed review of articles, research papers, reports, and case studies to analyze the challenges associated with well abandonment in regions susceptible to earthquakes.