Integrating Production Analysis as a Plan of Pattern Selection for Chemical Flood Pilot Project in Limau Block, Pertamina EP

Abstract

Limau Block, operated by Pertamina EP lies in South Sumatera basin, located 90 Km Western part of Prabumulih. Consisted of eight fields, the first well was drilled in April 1951. The production reached a peak of 49,000 BOPD. The reservoir was divided into 22 layers mainly due to faulting. The pilot water flood operation was initiated in April 1991 by injecting water. Currently, Limau block is a mature oil field. By April 2009 production had declined to 10,000 BOPD. It is estimated that more than 80% primary reserves have already been produced and recovery factor has reached 36 %. Most of the reservoirs have been intensively produced over the life of the field and only a few of them are still producing today at low rate due to depletion. EOR department tried to identify reservoir with remaining production potential that are candidates for Pilot Chemical Flooding Project, which will be the first Chemical Flood Project for Pertamina EP. The chemical selection is ongoing progress. It has become much more of a challenge for the team consisting of integrated Geophysics, Geology, Reservoir, Production, Process Facility, Project Management and Economic Evaluation. This paper presents the result of Production Part as integrated analysis for Chemical Flooding. The analysis, which was performed by integrated analysis of production and injection, tracer test, well history and surface data, has identified inter well communication between injection well and production well. It shows that the most prospective candidate for Chemical Flood pilot project was S layer in Q-51 field, the pilot project was planned for inverted five (5) spot patterns and predicted breakthrough time was 90 days, it was also predicted a tertiary peak of 3,100 BOPD. Currently, Q-51 field, which had reached a primary peak of 20,600 BOPD and secondary peak of 2,000 BOPD, is injecting 36,820 BWPD through seven (7) peripheral injection wells and producing 31,031 BFPD through 13 production wells. This analysis is useful result as a part of countercheck for Geology and Reservoir Modeling regarding to the plan of Chemical Flooding Pilot Project.