Managing limited subsurface data in a mature oil field case study: extending the production lifetime of a 50-year-old oil field in Indonesia: Rantau oil field Waterflood Pilot Project

Business management of oil and gas in Pertamina State Oil enterprises was handed to one of its subsidiaries: Pertamina EP (PEP). With a vast working area of 140,000 km2, it consists of 214 fields where 80% is an old field (mature field or brown field). Most of these oil fields were discovered during Dutch colonialism. One of these fields was Rantau oil field, discovered in 1928; it is considered one of potential structure at the time. Peak oil production was achieved at 31,711 barrels of oil per day (BOPD) (wc 17.2%) in 1969, and it is still producing 2,500 BOPD from primary stage. To get better recovery from the Rantau oil field, it is necessary to identify the potential of secondary recovery water-flooding. Some screening criteria had been completed to select an appropriate method that could be applied in the Rantau Field. PEP is preparing an Enhanced Oil Recovery (EOR) program to be applied in some oil fields with subsurface and surface potential consideration. The implementation was initiated by the EOR Department at PEP. The issue of the national oil production increasing program from the government has to be realised by the EOR Department at Pertamina EP. Following the national oil increasing program, management of PEP urged to increase oil production in a rapid and realistic way. As a result, the program of secondary and tertiary recovery pilot project should be conducted simultaneously by the EOR Department on some of the fields that have passed their peak. On the other hand, PEP has only limited geology, geophysics, reservoir, and production (GGRP) data, and most of the oil fields have been producing since 1930s. The conditions that have to be dealt with are as follows: production from the existing field is declining, data is collected and interpreted during a long period, huge amounts of production data, and reservoir model and simulation do not exist and are not frequently updated. Based on this, the planning of EOR struggled due to length of time needed versus the need for quick development. 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 extended abstract presents the term of managing limited GGRP data that contributes to the successful pilot waterflood project in the Rantau Field. It also explains the uses of limited subsurface GGRP data to overcome the uncertainty for planning of the waterflood pilot project in the Rantau Field, as a part of planning using limited data.