Birth Of A Metropolitan Waterflood

Abstract During the formation of the North Wilmington Unit, it was recognized that production response from adjoining improved recovery units indicated that an accelerated program would be necessary to assure the equitable distribution of oil reserves in the unit area. The North Wilmington Unit operators charged Sun Production Co. with development and implementation of Production Co. with development and implementation of am accelerated development program. This approach resulted in unitization, plan of development, plan of operations, design of equipment, acquisition of equipment, procurement of right-of-ways, construction of surface facilities, and development drilling being completed within a 4-year period. The time frame of this paper covers the development of this waterflood project from beginning of operations by Son Production Co. of properties acquired from Signal Oil and Gas in Jan. 1973 through the completion of the development drilling program in Dec. 1976. Many difficulties were encountered and this paper describes how these problems were solved through the application of sound engineering, good planning, teamwork, and creative problem solving. The experience gained in this unitization work can be applied to any similar project in a metropolitan area with problems of equipment project in a metropolitan area with problems of equipment design, right-of-way problems, and drilling activities. The principles used in developing this unit are somewhat unique because the area of operation is highly congested with people, roads, junk yards, refineries, and houses. INTRODUCTION (SEE FIG. 1) The North Wilmington Unit contains the last major section of the Wilmington field to be unitized for secondary recovery. Production of reservoir fluids from the Wilmington field resulted in surface subsidence. The California Subsidence Act of 1958 provided for unitizing and development of provided for unitizing and development of waterflooding to inhibit subsidence. Nine units have been formed under the subsidence act since 1958, including the North Wilmington Unit. This project is located in Los Angeles County, primarily in the Wilmington district of the City of primarily in the Wilmington district of the City of Los Angeles, with a portion in the City of Long Beach. The 1,000-plus-acre unit covers an area with town-lot spacing that includes homes, small businesses, small manufacturers, and a major refinery. The unit area is also crossed by various highways, railroad tracks, and a flood-control channel. Discovery of the Wilmington field occurred in 1936 with development of the project area occurring in the 1940's. One Hundred and twenty-six wells drilled on 5- to 7-acre spacing remained in the unit area in Jan. 1973, with only 11 wells plugged and abandoned. Because of the multiplicity of small leases, 63 tank batteries were in operation with most serving one to three well leases. Attempts at unitization of the area for waterflooding began in 1966. Sufficient agreement was never reached among the many operators and royalty owners to establish a workable project. Acquisition of the remaining interest by Sun Production Co. in properties operated by other companies in the area properties operated by other companies in the area provided the incentive for Sun to purchase additional provided the incentive for Sun to purchase additional properties in the last quarter of 1972. properties in the last quarter of 1972.A preliminary study of the secondary recovery potential resulted in several conclusions. All other potential resulted in several conclusions. All other waterflood units in the Wilmington field are very successful. Oil migration, caused by long-term injection in offsetting waterfloods and accelerated by boundary line injection since 1971, necessitated prompt unitization and development. prompt unitization and development. An operators meeting was held to review the preliminary report and to solicit approval to proceed. preliminary report and to solicit approval to proceed. All operators agreed that engineering and geological committees should be formed to develop an accelerated secondary recovery program. The committees completed the Technical Committee Report in Aug. 1973. It was submitted to the operators and approved in the last quarter of 1973.