Integrated Pore Pressure Prediction with 3D Basin Modeling

Basin scale examination of pressure conditions is important from many aspects. On one hand well planning requires the understanding of the pressure regime, on the other hand abnormal pressure conditions could affect the behavior of the petroleum system. The upper boundary of the overpressured zone was identified on wireline logs. Comparison of the pressure trends with the lithology sensitive logs suggested that the overpressure generation relates to shaly strata. Two sedimentary environments were formed during the Late Miocene sedimentation cycle where shale rich sediments were deposited: delta slope and foreground of turbidite systems. As the formation of abnormal pressure regime relates to low permeability sediments the main overpressure generation mechanism might be the non-equilibrium compaction. This theory is confirmed by the well log signatures of these sections. Beside the non-equilibrium compaction at least two other mechanisms could improve the overpressure, i.e., clay mineral transformation and lateral transfer. The basin modeling is an alternative methodology for the pressure regime investigation. A 3D basin model was built to test the technique. This approach allowed to investigate the effect of the lateral transfer and the hydrocarbon generation too. Furthermore, information about the timeframe of the overpressure emergence was gained.