The integration of high quality sequence stratigraphic analysis plays an important role in the 3D modeling of reservoir facies and petrophysical properties. It provides a better characterization of complex geology and helps to reveal hidden pays that may not have been found with conventional techniques. This paper demonstrates the benefits of effective sequence stratigraphic interpretation in creating a holistic 3D reservoir model and in identifying probable hydrocarbon traps in the study area.

The paper establishes a sequence stratigraphic framework, consisting of two lowstand system tracts (LSTs), one highstand system tract (HST), and one transgressive system tract (TST), using integrated interpretation of well logs and seismic data. Studies of the depositional pattern of the framework revealed three main sedimentary facies (marine, flood plain, and fluvial) with complex lateral and vertical relationships. In conventional approaches, a global facies average calculation is assumed, creating an unrealistic model with a stationary condition. In this study, layer-wise facies trend maps were generated, using lithotype proportion map (LPM) and vertical proportion curves (VPC), to capture the geological inhomogeneity. While making the model geologically more realistic and non-stationary, facies boundaries from the sequence framework are honored by constraining the final 3D facies simulation through customized lithotype rules. Next, a petrophysical property modeling technique is used to populate individual litho-groups for porosity, saturation, and total organic carbon (TOC) by interval and constrained by facies. This process leads to a holistic, geology-controlled 3D reservoir model that reveals hidden pockets of LSTs with high porosity values in the reservoir, which provide promising exploration sites for future development. This study also shows that the TST has an abundance of high value TOC; consequently, it is more likely to be genetically related to the source sediments. In conclusion, the integration of sequence analysis played a significant role in the development of a realistic 3D distribution of reservoir facies, providing a better prediction of reservoir properties, increasing recovery, and reducing uncertainties in field development.

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