Integrated Geological and Geophysical Approach to Reservoir Modeling: Case Study of Jambi Sub-basin, Sumatra, Indonesia

Integrated geological and geophysical investigations were successfully performed for reservoir modeling in an oil field in the Jambi Province sub-basin, Sumatra, Indonesia. The objective of this study is to characterize the oil reservoir in terms of its petrophysical properties using a facies model that is based on an integrated geological and geophysical approach. The reservoir target of this study is located in the Air Benakat Formation, which is identified with a thickness of 3 to 20 m and is deposited in a depth range of 1300–1500 m. The reservoir modeling of Air Benakat Formation is carried out to open a new discovery for this field, since the comprehensive reservoir modeling has not been intensively performed. Structurally, the reservoir is segmented into three compartments by four main faults, and stratigraphic investigations revealed three prospect layers. In the present framework of the depositional environment, assessments of well log data included formation evaluations, well log data correlations and sequence stratigraphy, were performed to produce high-resolution features of vertical and lateral distributions. In addition, seismic data were interpreted to guide the structural model, and to effectively construct a three-dimensional (3D) geological framework of reservoir properties. The modeled reservoir shows that the reservoir is primarily considered a transition zone to a shallow marine deposit, which is specifically located in a submarine fan channel with a plain/moderately steep angle of its sedimentation base. Depositional environments are generally characterized by the potential paleocurrent direction within the channel axis from NE to SW, with respective agreement from larger scale porosity and net/gross models.