Waterflood Management in Spring Field

Spring Field was discovered in 1963 and started production in 1965. Waterflooding began in 1999 in one reservoir and has subsequently expanded to nine reservoirs to date. Waterflooding in the Spring Field is basically a peripheral water injection system with the use of brackish water as injection water. Waterflooding in Spring Field has been instrumental in "arresting" base decline, sustaining and re-pressurization of depleted reservoirs. There are currently 29 active producing reservoirs in the Spring Field with waterflooded reservoirs accounting for ~ 63% of current oil Production and ~ 52% of the estimated ultimate recovery (EUR). The management of waterflood systems can most often be quite challenging with Spring Field not being an exception. Waterflood challenges observed in Spring Field include both surface and subsurface issues such as non- uniform volumetric sweep due to complex reservoir architecture (Compartmentalized/ Multi-lobed Reservoirs), long fill-up time due to late startup of water injection, unbalanced Injectivity, out of zone injection, injection pumps reliability to mention a few. Managing and resolving these issues would therefore require a systematic and logical structured approach to ascertain the "health" of the Waterflood system in place with the overall objective of improving its efficiency, hence the purpose for this paper. This paper focuses on the use of the Surveillance, Analysis and Optimization (SA&O) workflow processes in the management of the water flood system currently in place in the Spring Field. The paper also highlights examples where this workflow process has helped in identifying gaps and optimization opportunities in the Spring Field. The Surveillance, Analysis and Optimization process include the following: ➢Surveillance- Acquisition of necessary data from multiple sources.➢Analysis- Review/ Interpretation of acquired data using various diagnostic tools. For ease of Analysis and Reviews, this element is subdivided into three distinct categories:● Health Check Category● Predictive Category● Problem Identification Category➢Optimization- Recommended corrective actions and efforts carried out to improve Waterflood efficiency based on observations from various analysis.