Well abandonment in the Los Angeles Basin: A Summary of Current Requirements, Practices and Problems

Abstract

Well abandonment in the Los Angeles Basin: A Summary of Current Requirements, Practices and Problems. Abstract Due to declining oil production increasing and real estate development, an increasing number of oil wells are being abandoned (or reabandoned) each year in the Los Angeles Basin. This paper summarizes the current requirements of the Department of Conservation's Division of Oil, Gas and Geothermal Resources (Division), the current abandonment practices of the industry and some of the difficulties encountered in properly abandoning or reabandoning wells. The paper has viewpoints from authors representing (1) the Division, (2) a major oil company with a large abandonment program, and (3) a consulting petroleum engineer engaged in reviewing wells and preparing abandonment programs. This paper is considered to be particularly timely and important as the petroleum industry endeavors to leave oil fields in such a condition that surface development can safely follow. Introduction The Los Angeles Basin is one of the most prolific oil producing basins in the world. It contains over 60 oil fields where cumulative oil production exceeds 8 billion barrels. Some of the major onshore fields and oil production are as follows: Oil production in 1995 in the Los Angeles Basin totaled 38.6 million barrels (106,000 B/D) from 4,900 producing wells. At the end of 1995 there were 3,081 idle wells. Most of these wells are abandonment candidates. During 1995, 498 wells were abandoned in the Los Angeles Basin (Table 1). Since 1988, the rate of well abandonments has increased significantly (Fig. 1). This paper discusses the current regulatory requirements, practices and problem related to abandoning wells in the Los Angeles Basin. A. Current Requirements Since 1915, the Division has been charged with regulating the drilling, operation, maintenance and abandonment of all oil and gas wells in California, to prevent damage to life, health, property, and natural resources. Under Section 3106 of the Public Resources Code (PRC) the State Oil and Gas Supervisor has the authority to regulate the manner in which the Division's programs are carried out in the best interest of public safety and ultimate recovery of oil and gas. In the early 1970's, additional safety concerns were raised by the Division regarding building in and near former oil producing areas. Although the oil and gas wells in these areas may have been abandoned properly in previous years, they may not be in conformance with today's more stringent abandonment regulations. The prevention or mitigation of methane gas migration from other sources into proposed or existing overlying structures also became an important matter for the Division; including, developers and building and fire inspectors. P. 701^