A study of legacy oil infrastructure near Summerland, California, has identified previously unknown connections between wells, methane plumes and additional seafloor faults and fractures that may provide pathways for hydrocarbons to reach the marine environment.
SANTA BARBARA, Calif. — A study of the Summerland seafloor and surrounding area is providing new information about legacy oil wells and hydrocarbon emissions that could help determine which wells should be prioritized for abandonment. Heal the Ocean is conducting the Summerland Oil Mitigation Study, or SOMS, to map the geology and infrastructure of the Summerland seafloor and surrounding area while developing a detailed understanding of hydrocarbon emissions from the region's legacy oil wells. The study is intended to provide information to the California State Lands Commission to help determine which wells should be prioritized for full abandonment. The commission has already abandoned eight legacy oil and gas wells in Santa Barbara County, but several hundred high-priority legacy wells in the Summerland area alone could leak oil into the marine environment. Preliminary findings from SOMS are revealing previously unknown connectivity between wells, along with methane plumes and additional seafloor faults and fractures that may provide pathways for hydrocarbons to reach the marine environment. “What we are learning in Summerland has significance far beyond this one oil field,” said Karina Johnston, executive director of Heal the Ocean. “SOMS is giving us the ability to connect emissions, geology, and infrastructure so we can identify which legacy wells are actually driving pollution and target abandonment where it can have the greatest benefit. Just as importantly, the team is developing a science-based approach that could be applied to aging oil infrastructure anywhere in the world, whether it is on land or underwater.” SOMS researchers have been collecting time-series data from two Meteorological Air Quality Trailers to track emissions from the Summerland nearshore oil field. Analysis of the data has revealed previously unknown connectivity between wells, information that could help determine which wells should be targeted during different phases of abandonment. During marine surveys this week aboard a research vessel, Heal the Ocean and its scientific partners at Bubbleology Research International also pinpointed several methane, or CH4, plumes using multiple technologies. The technologies included methane detection systems, live-stream multi-beam sonar, water quality sensors and a crude-oil sensor capable of detecting concentrations down to approximately 1 part per billion. Researchers also identified more faults and fractures on the seafloor than had previously been mapped. Those geological features may represent additional pathways for hydrocarbons to migrate toward the seafloor and surrounding waters. SOMS combines air-emissions monitoring with seafloor mapping, water chemistry analyses, meteorological data, aerial observations and other measurements to create a more complete picture of legacy oil fields. The goal is to develop a repeatable technique for identifying problematic wells and aging oil infrastructure based on their emissions and geological characteristics. The resulting methodology could potentially be used in other coastal oil fields around the world to help regulators and communities identify pollution sources. For Summerland, the immediate objective is to provide the scientific information needed to help Heal the Ocean and the California State Lands Commission determine which legacy wells should be abandoned next and how abandonment can be most effectively sequenced. The study is funded by the California Ocean Protection Council, Nora McNeely Hurley Foundation and Mericos Foundation. It is scheduled to be completed in December 2026, with findings to be shared publicly.
