Publications

MDC-01 was the first gas exploration well drilled in Block A-Aceh, North Sumatra Basin in almost 20 years. The reservoir objective of the well was Early Miocene Carbonate, Member of the Bampo Formation. Both high pressure and high temperature were encountered during drilling. Other challenges were well kicks and drilling fluid loss circulation in both the Peutu equivalent section (partial and total losses) and the Carbonate Bampo equivalent (total losses). Various attempts to handle the kicks and loss circulation were undertaken using loss circulation material, gunk pills, and cement plug squeeze. As is the case during total loss or blind drilling, rock cuttings and mud gas readings were not obtained. Even with the increased drilling risk, we decided to continue drilling using a two-phased logging approach that included a specialized logging tool. Halliburton’s Thermal Multi-Gate Decay Lithology log (TMD-L) (a thermal-pulsed neutron capture tool) was used as a cased-hole tool in the drill pipe for a phase one logging run due to unsafe conditions for open-hole logging in the Carbonate Bampo equivalent. The tool was used to identify lithology and confirm possible fluid type. Gamma ray, Sigma Yield Carbonate, and Yield Silica were the outputs of the TMD-L used to identify the lithology. Fluid typing was based on the crossover between pseudo density and pseudo neutron and the also crossover between Far Space Capture Count Rate and Near Space Capture Count Rate. In phase two, open hole logging (standard gamma ray, sonic, and resistivity) was performed after the well conditions were declared safe. Ultimately, the TMD-L logging results were depth adjusted and compared to the standard high temperature open-hole logging tool results to evaluate subsurface lithology and potential pay. Based on the combined well logs analysis, a DST was performed over the interval 7812–7880 ft MD. The MDC-01 well flowed around 25 MMCFD gas, thus highlighting the remaining potential in Block A, North Sumatra Basin.