f Jerneh Full Field Studies – an Integrated Approach to the Identification of New Development Opportunities

The ExxonMobil-operated Jerneh field is the largest non-associated gas field in the Malay Basin. The field was discovered by the Jerneh-1A well in 1969, and production commenced from the Jerneh-A platform i 1991. Depletion mechanism is via natural depletion with the Miocene primary reservoirs now up to 80% depleted. A multi-disciplinary team was formed in 2003 to study available field performance data and identify further development opportunities. This paper outlines the integrated approach taken by the geoscientists and engineers in the study team to mature new drilling opportunities. Three different types of development opportunities were generated by the team and formed the basis for the 2006 drilling program: 1. Additional resources in the western part of Jerneh were identified through field-wide stratigraphic remapping, incorporating recently re-processed 3D seismic data and integrating available production data. 2. Crestal locations with under-filled reservoirs, together with depleted reservoirs containing gas trapped by GWC movement were identified during recent drilling and logging programs. 3. Re-evaluation of petrophysical analyses shows higher gas saturations in several of Jerneh’s “minor” reservoirs. This has resulted in attractive infill opportunities in these marginal quality reservoirs. The study resulted in an appraisal well and a five-well infill drilling program for 2006. The appraisal well (Jerneh-6) has already confirmed sufficient resources in the western area of the field to justify a new production platform for an additional six development wells. The infill drilling program is ongoing with 3 out of 5 wells completed, with results to date meeting expectations. The application of ExxonMobil’s Fracture Closure Stress (FCS) drilling technique was instrumental in the successful drilling of the recent appraisal and development wells. This technique enabled the successful penetration of multiple severely pressure drawn-down reservoirs without significant fluid losses. The key to the success of the Jerneh Field Study was the multi-disciplinary integration of available geoscience and engineering data. Close collaboration among all the team members was essential in identifying further development opportunities in this mature field environment. A more comprehensive understanding of<br>the reservoirs was achieved, and forms the basis for Jerneh’s future development plans, including the upcoming Jerneh-B development project.