Overpressure mechanism prediction based on well log and mineralogy analysis from drill cuttings of well NSE-001 in the North Sumatra Basin area, Indonesia

Abstract The well NSE-001 is an exploration located in the North Sumatra Basin, Indonesia, which penetrates several formations with overpressure zones that have potential as a drilling hazard this area. results of pore pressure fracture gradient model show response wireline log data based on normal compaction trend has two types mechanisms, namely loading and unloading. Rapid sedimentation development Lower Baong Formation Upper thick massive shale sequences Basin main factor generation zone mechanism. This correlates travel time sonic relatively constant to at depth intervals 620–1500 mMD (from Middle Sand Top Gebang Formation). presence sillimanite kaliophilite minerals bulk analysis from drill cuttings 2200–3820 contributed hydrocarbon, while clay showed mineral content kaolinite + illite alteration product (clay diagenesis) was higher than smectite. mineralogy (bulk clay) correlated trend, interval 1500 m 3200 Belumai Formation) unloading mechanism, characterized by fluid expansion caused diagenesis possibly hydrocarbon generation.