Project Profile
Value: US$180 million
Location: Offshore Mahakam Block in East Kalimantan, South China Sea, Indonesia
Reserves: 16.5 tcf
Water Depth: from 2,200 to 4,900 m
Start-up Year: -
Tunu field, discovered in 1977, is an elongated structure, comprising complex, stacked reservoirs, stretching 80 km from north to south in shallow waters (swamp area) along the outer limits of the delta offshore Mahakam Block in East Kalimantan, South China Sea in Indonesia. Tunu is a gas/condensate field containing only negligible CO2 or H2S, with the main productive reservoirs lying at depths from 2,200 to 4,900m. Recoverable reserves are estimated at 16.5 tcf. Under the first-phase plan of the late 1980s, gas from Tunu was collected by gathering and testing satellite installations (GTSs) in only a few feet of water.
Between 1994 and 1996, production steadily ramped up through five new development phases. Early in 1997, the partners launched a seventh phase to improve operation of depleting wells on South Tunu. This program involved adding:
- A 4,000-ton medium pressure compression platform, TCP, operating at up to 400-450 MMcf/d, with a 700-ton air cooler support frame – equipment includes two slug catchers, one TEG dehydration unit, and two LM 2500 gas turbine-driven compressors
- A manifold platform with a 400-ton deck, and a scrapper trap platform with a 300-ton deck to collect effluents from the compression reception facilities
- Two networks of associated medium pressure pipelines (20 km of 20-in. lines and 25 km of 36-in. lines).
Just after the new plant became operational in late 2000, an eighth phase was under way, applying a similar range of facilities to Tunu North. Here, a new mid-pressure compression plant (NCP) has been installed close to the NPU, with a manifold platform and surface pipeline network also added to address existing production/transportation bottlenecks. At the end of 2002, a ninth phase was started, involving the addition of a new GTS in both the north and south of the field. This will bring the total of satellite installations across the field to 20, collecting a total of 1.5 bcf/d. The GTSs are a standard design, with a dry deck weight of 250-350 tons, an average of 10 wells spaced in a regular pattern, and all capable of producing up to 200 MMcf/d.
Around 240 development, delineation, and exploration wells have been drilled on Tunu, of which 60% are still active. A 10th development phase is already being planned that will include reduced well spacing, and an extension of certain GTSs for infill drilling through installation of additional well slots. The production from Tunu could be extending well beyond 2017. Tunu’s basic design has been performed by Doris Engineering. Local fabricator PT Gunu Nasa has built all the platforms at its yard in West Java. A Canadian drilling contractor, PT Santa Fe, is drilling the current wells.
Operators:
Total E&P Indonesie (Total): Operator with 50% interest
Inpex Indonesia: 50% interest
Contractors:
Doris Engineering: Tunu’s basic engineering design
PT Gunu Nasa: EPC contractor for all the platforms using its yard in West Java
Santa Fe: Drilling contractor