Adnan, M. Mohd (Carigali-PTTEPI Operating Company) | Ismail, W. Wan (Carigali-PTTEPI Operating Company) | Kaewtapan, J. (Carigali-PTTEPI Operating Company) | Setiawan, A. S (Carigali-PTTEPI Operating Company) | Tanprasat, S. (Carigali-PTTEPI Operating Company)
A comprehensive technical evaluation was conducted after the completion of six exploration and appraisal wells to assess the future petroleum potentials in North Malay Basin, offshore Malaysia-Thailand Joint Development Area (MTJDA). This paper focuses on major discoveries and findings from key wells, namely Well-E3, Well-A2ST, and Well-T3 to better understand the petroleum potentials for the subsequent development planning.
Well-E3 and Well-A2ST were drilled to investigate the stratigraphic trap play in the eastern flank of MTJDA and to explore the hydrocarbon potential in deeper depositional sequence below DS10 interval. The seismic dataset and amplitude analyses were used to identify channel fairways and qualitatively predict sand presence for well planning optimization. Both wells encountered gas-bearing sands with proven stratigraphic trap style, requires channel orientation oblique with the axial anticline structure. Full integration of well log dataset, formation pressure test and seismic attribute analyses have proven the exploration intervals with gas-bearing sands discoveries. In addition, rock physics analysis was performed to differentiate gas from wet sand and coals.
Well-T3 was drilled in the western flank to appraise the seismic anomaly associated with hydrocarbon sand and to investigate the CO2 content in the southernmost extension of hydrocarbon accumulation. The anomaly is observed as two distinct sand fairways of channel-bar complex. The northern lobe was dissected by deep seated fault system with high CO2 content. The southern lobe appears to be free from deep seated fault system. Well-T3 was drilled in the area where CO2 pathways was expected to have no connection with deep seated fault system and lower CO2 content than the main area. Formation pressures, samples and seismic anomaly supported the hypothesis that the northern and southern culminations are not connected with significant stratigraphic heterogeneity interpreted. An important oil discovery was also observed from pressure gradient and samples as the first oil discovery in the western flank.
Full integration of the well log dataset, formation pressures, seismic attribute analyses and rock physics modeling have resulted in an improved understanding of reservoir distribution and reduced the degree of uncertainty in reservoir connectivity, thus allowing a more robust development strategy. The new discoveries of proven stratigraphic trap in the eastern flank with deeper hydrocarbon culminations and proven oil discovery in the western flank with enhanced understanding of CO2 content have triggered more future petroleum potentials in MTJDA acreage.