Site History

The former Guadalupe Oil Field, now referred to as the Guadalupe Restoration Project, is an area rich in biological and cultural resources. Oil exploration and production began at the property in the late 1940s. During the operating life of the site, diluent, a refined hydrocarbon similar to kerosene, was used to reduce the viscosity of the heavy crude in oil wells.

Oil production ended in 1994 and Unocal purchased the property in 2002. As Chevron continues the restoration work started by Unocal, we will continue to work closely with regulatory, environmental, and community stakeholders to preserve this sensitive habitat while we fulfill our commitments.

  • Guadalupe oil fields 1947


    Oil production began at the Guadalupe Oil Field.

  • Guadalupe oil fields 1953


    Union Oil acquired the Guadalupe Oil Field.

  • Guadalupe oil fields 1955


    Diluent, a kerosene-like hydrocarbon, was placed into the wells to improve flow of the heavy crude oil.

  • Guadalupe oil fields 1990


    Use of diluent was discontinued.

  • Guadalupe oil fields 1994


    Union Oil ceased all oil production from the field. Project and remediation work started under an emergency permit from the United States Coast Guard.

  • Guadalupe oil fields 1998


    San Luis Obispo County Board of Supervisors, Regional Water Quality Contrail Board, California Coastal Commission, California Department of Fish and Wildlife, US Army Corps of Engineers, US Fish and Wildlife Services, and US EPA approved a plan to clean up the diluent that leaked from pipelines in the field and remediate the oil field.

  • Guadalupe oil fields 2005


    Chevron acquired Union Oil and continued the remediation work.