Sustenance and Management of a Matured Waterflood - A Niger Delta Case Study

Abstract

Abstract The field started production in 1965, it is structurally complex, comprising of several structural closures contained within three major fault blocks. The flooded reservoir block discussed in this paper came into production in 1965. Rapid pressure decline (55 psi per 1 % of STOIIP produced) was observed in the early production life of the reservoir. The rapid reservoir pressure decline caused shrinkage losses and expansion of the gas cap; this in turn resulted in production problems. A case for water injection was made & full-scale water injection commenced in 1978 with 3 injection wells taking water from a shallow aquifer through 2 source water wells. In addition to arresting further reservoir pressure decline, the project protects a reservoir production rate of 3.5kbopd and safeguards up to 10 MMstb remaining reserves. The water injection project like many matured waterflood systems operated under matrix conditions was plagued by frequent loss of injectivity & surface facility integrity issues coupled with the peculiar security situation of the Niger Delta. This paper describes; How well & surface challenges with the water injection project have been resolved Continuing operational and performance monitoring methods to sustain and optimally manage the peripheral water injection