Facility Decommissioning Offshore California
Authors: Bybee Karen 
Published: February 2015

This article, written by Assistant Technology Editor Karen Bybee, contains highlights of paper SPE 94390, “Offshore California Facility Decommissioning: Past, Present, Future,” by P.B. Mount II, SPE, and M. Voskanian, SPE, California State Lands Commission, prepared for the 2005 SPE/EPA/DOE Exploration and Production Environmental Conference, Galveston, Texas, 7–9 March.

Decommissioning of offshore oil- and gas-production facilities in California has always been and will continue to be a controversial and hotly debated topic. This decommissioning most recently involved four offshore platforms, a pier, and an island in state waters. It also involved the abandonment of more than 23 subsea wells and associated debris off the Santa Barbara, California, coast. The full-length paper summarizes the lessons learned from past decommissioning projects and options available for future projects.

Introduction

Development of offshore oil and gas in California began early in the 20th century with the drilling of wells from piers set off the central California coast. Many of these wells were drilled before regulations concerning drilling and abandonment were as comprehensive as they are today. The first offshore field in the United States was at Summerland in 1894. Fig. 1 shows the many piers that were set in the Summerland field between 1894 and 1903. In the early 1900s, offshore facilities were usually decommissioned because of pier deterioration, fires, or storm damage. Lack of adequate policies and techniques for abandonment and decommissioning during that time is creating a problem even today because of the potential for oil to leak from improperly plugged wells and because of debris left on the ocean floor.

Today the California State Lands Commission (CSLC) is responsible for leasing and management of mineral resources in state waters. The CSLC’s jurisdiction includes sovereign tide and submerged lands adjacent to the coast and seaward to 3 nautical miles. This state agency did not exist until 1938 and did not lease offshore land for the installation of offshore facilities until 1954. Before that, many wells had been drilled from piers or slant drilled from the coastline to offshore. Leases issued for development of oil and gas from offshore facilities generally provide that, at the election of the state, the facilities must be removed and the surface of the ocean floor restored.

Participants

Some parties that have a stake or are interested in the practices used for decommissioning offshore structures include the state of California; the federal government and the Minerals Management Service (MMS), because the federal government manages the land seaward of the 3-mile limit; environmentalists because of their concern about damage to the environment; local government agencies because of the effect on onshore residents; and the public because of conflicts with their use and enjoyment of the ocean. In California, many offshore facilities are close to land and highly visible; thus, decommissioning has become a very controversial issue. There are many other private and public organizations that have an interest in or play a role in establishing policy and practices concerning offshore decommissioning.