Sanga Sanga block has been producing for more than 50 years, with most of the oil production from depleted reservoirs with 60% of base production decline. Extending the wells’ lives requires aggressive artificial lift development both in subsurface and surface. The implementation of gas lift supply strategy is very critical to fulfil gas lift capacity requirement also with sufficient injection pressure. This paper will describe gas lift supply strategy consisting of facility upgrading, along with integration and optimization of the existing facility.
Thorough project planning and procedures have been established to ensure the optimum oil development. The gas lift facility upgrade consists of three main projects as follows. The first was a major project of an additional high pressure compressor for gas lift. One unit in the Mutiara field and two rental units in the Nilam field have been installed to increase gas lift capacity.
The second project was the installation of an interconnected gas lift network to ensure availability and coverage of gas lift system along from gas lift source to the furthest well location. The last project was the optimization of the existing production facility, injection facility and trunkline to reduce capital cost.
This project was completed as scheduled and successfully delivered 10,000 BOPD in the last four years. It was supported by an additional 27 MMscfd supply from the HP Compressor project as a gas lift source.
A length of more than 35 km of gas lift system was completed in 6 producing fields to eliminate gas lift blank spot. Gas lift injection pressure has increased from 300 - 1000 psig to 1400 to – 1800 psig, enabling more drawdown in the gas lift wells. The interconnection system installed gives two benefits: flexibility of gas lift source during compressor maintenance and also the distribution of High Pressure and Medium Pressure gas. Sanga Sanga also managed to reduce the unit price of the individual gas lift injection facility by 30% through a bulk procurement strategy, utilization of idle equipment and the modification of existing equipment.