A Case Study on Multiple Stratigraphic Reservoirs Related with Weathered Granite Buried-hill

The Betara buried-hill is located at the northern margin of South Sumatra back-arc rift basin in Indonesia. Its basement lithology is composed of phyllite, granite and metaquartzite. It is a mature area with six condensate and/or gas fields discovered. The new challenges meet with hydrocarbon exploration. Based on the integrated geological and geophysical study, Betara granite buried-hill geological model is established, which the granitic weathered rind and granite leached fracture zone formed at the basement, and the alluvial fans on the ramp from in rift stage from Eocene to Oligocene. They are effective factors of the model that three plays of the multiple stratigraphic reservoirs formed in Betara complex. A patch of new prospects are identified. The multiple stratigraphic reservoir model of granite buried-hill is a good petroleum exploration reference in South Sumatra basin.