THE SEISMIC CHARACTERISTICS OF THE LANGSA 'L' CARBONATE BUILD-UP THE FIRST OFFSHORE OIL PRODUCTION IN NANGGROE ACEH DARUSSALAM PROVINCE

摘要

Soon after the Tsunami hit Nanggroe Aceh Darussalam province on December 26th last year, oil lifting from the L Field Langsa TAC resumed and oil was delivered to the Balikpapan refinery in East Kalimantan. Geologically, the L Field is a carbonate build-up located on the up-thrown side of the north-south trending Ibu Horst block.rnSeismic surveys have been conducted in this area since 1968, soon after the first PSC contract was introduced in Indonesia. In 1981, after oil discoveries were made in the L-1 and L-2 wells from the Malacca Formation carbonate build-up reservoirs, Mobil Oil Indonesia conducted a 3D seismic survey covering the L Field. Seismically, drape seismic reflectors over the L build-up and on-lap reflectors on top of the carbonate build- ups have been observed.rnBased on well correlation, about 100 milliseconds Two Way Time (msec TWT) of Malacca Limestone was observed at L-1 well and about 30 msec TWT at L-2 well. Seismic well ties recorded from L1 and L2 well checkshot surveys were quite good and acceptable for generating a depth structure map.rnIn order to obtain a geological model of L Field reserves through reservoir simulation, an inversion study using Humpson Russell software was conducted. Using multi-attribute analysis, MML (Medco Moeco Langsa Ltd) has developed an optimum approach to define porosity distribution in L Field.