Thin reservoir characterization using geostatistical seismic inversion approach: Applied to Central Sumatera Basin field

摘要

Geostatistical seismic inversion has been successfully applied to Central Sumatera Basin Field. This field consists of multiple thin sand reservoir layers, which is the member of Bekasap Formation. In stratigraphic trapping, multiple thin sand reservoir layers were geologically pinching out to the basement. The depositional environment of this reservoir was indicated by three different facies, estuarine channel facies, estuarine shoreline bar and estuarine bar. The facies show that the Bekasap formation in this field is generally deposited in the estuarine environment to the shallow marine. This research applied the geostatistical method to know the resolution limit of Bekasap Formation on-lap layer, where it can be used for drilling well recommendation in the development stage. The geostatistical method is popular to enhance the seismic appearance. It can show the layer which is beyond the maximum of seismic resolution. In addition, the geostatistical seismic inversion produces multiple realizations which consider the seismic data and the well data. Our experiment shows that better vertical resolution was achieved by the geostatistical seismic inversion compared to deterministic seismic inversion. The method successfully imaged the thin layer on Bekasap Formation by the resolution limit of 5 m, means that the thin reservoirs under 5 m were able to detect. Thus, the on-lap feature on the target area was perfectly imaged.