Abstract

Development of marginally economic oil and gas accumulations south of the E field, Offshore Northwest Java (ONWJ) is being accomplished with innovative methods developed by a multi-disciplinary team. The use of 3D seismic, reservoir zonation, horizontal, long-reach drilling, and innovative facility structures are contributing to the effort. The study area contains 5 proven hydrocarbon accumulations that have multiple sandstone and carbonate reservoirs in the Main/Massive and Talang Akar Formations. Only one of the accumulations, ESA, is currently being produced. Development of the others has not yet been pursued because of marginal economics.

Five wells from the ESA platform have produced a cumulative 8 MMBO primarily from the Main ES- 31A sand, which at ESA is a blocky sand up to 65' thick. Structural mapping showed two opportunities for ES-31A infills: one on a fault block that seemed to be independent of the producing structure, and another updip from an existing watered-out penetration. The wells were drilling challenges because of their long reach. Horizontal completions were planned to avoid early water coning, which characterized production from the original wells.

Another two wells from the ESA platform targeted the Talang Akar Formation where oil and gas were tested by exploratory wells. Both of these wells were successfully completed; they represent the first Talang Akar production from the entire E area.

South of ESA, several accumulations in the EST and ESS area will be exploited with a combination of innovative drilling techniques and facility design. Rather than a conventional platform, the production facility will be a "cluster" of three conductor pipes welded together. A multi-lateral well with two DHI targets in the ES-31A in the EST area will be drilled through one of the conductors. Two other wells are planned for Main/Massive and Talang Akar objectives in ESS. The cluster facility and multi-lateral wells will be the first use of these techniques for ARCO Indonesia. If successful, these techniques will open up other marginal fields for development.