Field X, Central Luconia, Offshore Sarawak, Malaysia, Early Appraisal Stage Reservoir Characterization

Miocene carbonates have been producing gas in Central Luconia for more than 30 years (Warrlich et al., 2019). Approximately 65 TCF of recoverable gas have been discovered to date in these build-ups (Scherer, 1980; Mahmud and Saleh, 1999; Khazali et al., 2013; Kosa et al., 2015; Warrlich et al., 2019). One of the most recent carbonate discoveries in this region, Field X, is in its early-stage of reservoir characterization. Depositional and facies models have been created with newly acquired data from LL-C appraisal well. Tectonics, accommodation, and sea level contributed to the overall shape and deposition of the carbonate buildup. One appraisal well, LL-C was drilled and penetrated a thick carbonate section on the structure. With the available data, facies and conceptual depositional models were created using well logs, sidewall cores, conventional cores, cuttings, seismic, and an extensive literature review. At the time of this study, core laboratory analyses were not yet completed. The reservoir is separated into five zones based on well log, core, and seismic data. A precursory facies model was completed using only photographs from the sidewall cores acquired in all five zones of the structure and photographs from conventional core acquired in the upper reservoir interval. Five facies were identified: Coral, Packstone, Wackestone, Mudstone, and Cemented Margin. The data acquired in LL-C illustrates the complexity of carbonate reservoirs and the need to acquire core early in the appraisal of carbonate reservoirs.