Optimum Development on Low Permeability Reservoir - New Phase Opportunity for Mature Badak Field

Hermawaty, Irma (VICO Indonesia) | Permana, Robhy (VICO Indonesia) | Silitonga, Frans (BP Indonesia) | Wijanarko, Andre (VICO Indonesia) | Soenoro, Amireno (VICO Indonesia)



VICO Indonesia is the operator of Sanga Sanga Production Sharing Contract (PSC) area in the onshore Mahakam Delta, East Kalimantan, Indonesia since 1968. Over 40 years, the PSC has produced more than 12 TSCF of gas through more than 800 wells to feed the Bontang LNG Plant and domestic market.  One of the major fields in the contract area is the Badak Field, which has contributed more than 6 TSCF of gas production.

Badak Field's reservoirs are the analog of the present day's Mahakam delta, and comprise of stacked distributary channel sands deposited in the deltaic environment draping on a four-way dip closure anticline. The shallower stratigraphic interval is dominated by fair to good quality upper delta plain, amalgamated channel sands, with a combination of water and depletion drive mechanism. The deeper stratigraphic intervals are dominated by fair to poor quality lower delta plain, more isolated distributary channel sands and mouth bar. The main reservoir drive mechanism is depletion drive.

As the early development strategy of the Badak Field had been focused mainly on drilling the best reservoirs, those shallow reservoirs in the crestal area, the majority of these reservoirs are now depleted. In contrast, low permeability deeper reservoirs with relatively higher reservoir pressure, still contain significant remaining resources. VICO's depletion challenge is to balance between increasing the recovery from the deeper intervals, whilst continue optimizing the recovery from shallow intervals.

An Integrated subsurface study has been conducted to understand the geological description of the reservoirs, ultimately to unlock the reserves of the deeper low permeability intervals. Several development options have been carefully evaluated, which lead to the implementation of new technologies to optimize recovery, including cluster wells, horizontal wells, and hydraulic fracturing. The results of the implementation of the development strategy and technology have been outstanding. This has helped sustain the Badak Field's decline rate at around 25% annually compared to a 45% natural decline. In 2011, the gas production was successfully maintained at 75 MMSCFD or 3 times the base line of the "do nothing?? case prediction, with more than 55 BSCF of reserves progressed.