Pressure prediction in structurally and stratigraphically complex areas using basin modeling approaches requires a good understanding of structural and diagenetic evolution of the basin. Typical models in such areas are based on a series of restorations that provide basic geometric description of the evolving system. They do not address the evolution of the mechanical properties of rocks through geologic time. Failure to appreciate this often leads to the wrong fault and host rock properties being utilized in the models, significant discrepancies with calibration data, and questionable charge and pressure predictions. In this paper, we discuss how such discrepancies can be utilized to iteratively improve the representation of fault rock properties. The proposed approach is an integration of basin modeling with diagenetic and mechanical analysis of fault and matrix rock properties. Examples from the Gulf of Mexico and Southeast Asia demonstrate how the approach helped to reduce fault- and seal-related uncertainty, which resulted in better hydrocarbon charge models and better pressure predictions.

ACKNOWLEDGMENTS:We thank Chevron Corporation for permission to present this work.

Figure shows an extract from a much longer Gulf of Mexico transect. Calculated effective stress reflects fault and host rock evolution and honors well data. Hot colors correspond to higher effective stress numbers, cool colors correspond to lower effective stress.

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