Publications

The M oil field is located offshore within the Malacca Strait PSC, Indonesia. The main reservoirs are high-relief sandstones in the Lower Sihapas Formation. They have porosity of 13 – 26 %, permeability of 8-9000mD, strong water drive, are under-saturated, with 43 API oil, and a low GOR of 200 SCF/STB. Oil production started in 1986 at a rate of 37,000 BOPD. The oil rate has declined over the years and in 2014 is600 BOPD from ten wells. The fluids are produced from commingled sands, and lifted with ESP’s. The current oil recovery factor is over 50%. High water cut sand old surface facilities are major challenges to further develop this field. The most recent development was in December 2010, when we drilled the M-10 well as an attic infill well. Unfortunately, it turned out to not be an attic location, as the six target sands came in 42-53 ft. deep to prognosis, and the oil had largely been swept by the strong aquifer to offset updip wells. Despite this disappointment, we did find clear indications of oil in the A-sand, and an untargeted Upper Sihapas Formation sand, and so we completed the well in these sands. However, deliverability was less than 100 BOPD due to depleted reservoir pressure and low permeability. In 2012, to look for attractive infill drilling and workover opportunities, we performed a reservoir modeling study using a geostatistical approach. We created 21 realizations to cover uncertainty in facies distribution, porosity-permeability and oil-water contact. We chose three realizations to represent ourP10, P50 and P90 cases. These three cases, and a recently run C//O log, both indicated that the B and E sands had producible oil, despite the negative indications from gas shows and logs. Encouraged, we ran nodal analysis, which showed no cross flow would occur if we commingled these sands with the existing perforated sands. Based on these studies, we performed a simple workover to perforate these sands. After the workover, the oil rate increased from 45 BOPD to 280 BOPD, with a one-year average rate of 217 BOPD. This paper tells how a combination of reservoir simulation, uncertainty analysis, C/O log and nodal analysis turned the M-10 well from zero to hero.