Integrated Production Analysis before Implementation Pilot Water Flooding and Surveillance & Monitoring during Pilot Water flooding on Rantau Structure Zone 600

Abstract

Rantau Field, located in the working area of PT. Pertamina EP, is considered as matured field. The field is located in North Sumatra, Indonesia. This field started producing in primary stage in 1930, and the secondary stage had been started in 1984 by injection of water. The water source comes from sea water with a salinity of 26000-33000 ppm. Since the injection of water quality is not good, then it had been damaged the injection wells, and it would automatically have an effect on the production wells. The oil production then started to decline.Pertamina EP EOR management team tries to increase the oil production back by implement re-secondary recovery process. The work started from field screening, study G&G, production analysis, preparing facility production, and follow up with a pattern pilot water flooding, and finally full scale project. Pilot water flooding kick off at layer Z-600 conducted in January 2010, Pertamina EP implemented a pilot water flooding in layer Z-600 block of C1 and C2 and managed to increase oil production from two wells (0 BOPD to 400-500 BOPD) and the reservoir pressure (from 155 Psi to 222.5 Psi in 3-month period conducted a pilot water flooding). With the success of pilot water flooding on the blocks C1 and C2, Pertamina EP will continue to full scale water flooding phases are planned to be carried out gradually in block A1 and A2. In addition to conducting secondary recovery, Pertamina EP will also plan for tertiary recovery phase for blocks/compartments that have been carried out secondary recovery activities. The production analysis is very important role in injection design, the scope include production and injection performance analysis, connectivity between injector and producer, pattern design and surveillance and monitoring.