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The onshore and shallow marine conventional hydrocarbon resources around the world are mostly at the maturation phase and hence, exploration activity globally, showing increasing interest into progressively deeper water hydrocarbon prospects such as South China Sea basins. However, a comprehensive understanding of basin tectonics, depositional history, and petroleum systems of the basin is required to deduce the exploration prospectivity of these deeper reservoirs. The Sabah Basin is a prolific hydrocarbon province in Southeast Asia and has a significant economic impact on this part. Recent discoveries in the deep-water hydrocarbon prospects in the NW Sabah Trough prompted a comprehensive investigation of the surrounding area, e.g., Dangerous Grounds for hydrocarbon prospectivity. Previous studies in the Dangerous Grounds mainly focused on the sparse 2D seismic and gravity-magnetic data analysis. A systematic review of stratigraphic evolution has not been presented thus far in the published literature. In this paper, recently acquired high-resolution 3D seismic data with the core and cuttings and conventional well log data from the adjacent areas have been combined to characterize the stratigraphic evolution of the Dangerous Grounds in the NW Sabah Platform. Seven horizons interpreted from the 7570 sq. km 3D seismic data, calibrated with the global sea - level curve and geological time scale, to establish the stratigraphic evolution in the study area. Based on distinct structural and seismic characteristics, and calibrated with the adjacent regions well data, two mega-sequences, namely, lower syn-rift and upper post-rift mega-sequences, have been identified and evaluated. The Paleocene to Early Oligocene syn-rift sequence consists of clastic sedimentary fill in grabens and half-grabens is overlain by Late Oligocene to recent post-rift sedimentary successions represented by siliciclastic and carbonates deposits. Major depositional units within these two mega-sequences, including carbonate, channel, mass transport deposits, and turbidites have been identified and evaluated. During Late Oligocene to Middle Miocene, the area has witnessed the deposition of carbonate platform and reefs on top of pre-existing structural highs. Late Oligocene to Middle Miocene channel-levee complexes with convex upward sand filling features is prominent in the seismic data. Mass Transport Deposits and turbidites have also been observed above the Middle Miocene Unconformity with distinct seismic characteristics. The pelagic and hemipelagic nature of the sedimentary succession deposited from Pliocene to recent in a passive margin condition have also been interpreted from their unique seismic features. Paleocene-Early Oligocene syn-rift siliciclastic hydrocarbon play, Late Oligocene-Middle Miocene carbonate play, and Late Miocene turbidite play within the study area have been interpreted. • Syn-rift clastic sediments deposited in between Paleocene to Early Oligocene age. • The significant presence of three types of reefs as patchy, pinnacle and atoll. • Late Oligocene-Middle Miocene convex upward sand filling channel-levee complex. • Mass Transport Deposits and Turbidites above the Middle Miocene Unconformity. • Pliocene-recent pelagic-hemipelagic sediments deposited in passive margin condition. [ABSTRACT FROM AUTHOR]

The Sabah Basin is a prolific hydrocarbon province in Southeast Asia and has a significant economic impact on this part. Recent discoveries in the deep-water hydrocarbon prospects in the Northwest Sabah Trough prompted a comprehensive investigation of the surrounding area, e.g., Dangerous Grounds for hydrocarbon prospectivity. Previous studies in the Dangerous Grounds mainly focused on the sparse 2D seismic and gravity-magnetic data analysis. A systematic review of detailed depositional history has not been presented so far in the published literature. To achieve this, recently acquired high-resolution 3D seismic data and well information have been used for seismic attribute analysis to establish the structural features and depositional pattern from the Paleocene to recent age. Two major sedimentary sequences have been evaluated from the seismic data, which include syn-rift and post-rift sequence. The pre-rift sequence considered to be the acoustic basement is overlain by syn-rift sequence, deposited during the Paleocene to Early Oligocene age. Spectral decomposition analysis demarcates paleo-lows/depocenters, consist of siliciclastic sedimentary fills in grabens and half grabens with the syn-sedimentary deformation. Geobody interpretation helps to understand the different phases of syn-sedimentary faulting with the presence of antithetic faults in the grabens. Late Oligocene to Middle Miocene carbonate platform and reefs has been observed on top of the pre-existing structural highs. Sweetness attributes enable to appraise the reef structure to demarcate lithofacies boundaries. Variance and amplitude extraction maps reveal the development of reefs on top of the carbonate platform. Amplitude extraction map reflects the Late Oligocene to Middle Miocene channel-levee complex with the convex upward unconsolidated sand filling pattern. Sweetness map helps to delineate the meandering channel boundary, channel geomorphology with ox-bow lake, point bar, and west to east channel shifting. Carbonate and clastic dominated areas have been differentiated in the southwest part. Slides and debris flow Mass Transport Deposits, Late Miocene turbidites have been observed above the Middle Miocene Unconformity and evaluated based on their distinct seismic characteristics. During the Pliocene to recent, the basin has witnessed the deposition of thick pelagic-hemipelagic sediments in the outer-neritic to the bathyal environment in the passive margin condition. • Pelagic-hemipelagic sediments deposition in outer-neritic to bathyal environment. • Slides, debris flow deposits and Turbidites above the Mid Miocene Unconformity. • Prominent evidence of Late Oligocene-Mid Miocene channel shifting from west to east. • Late Oligocene-Middle Miocene meandering channel with oxbow lake and point bar. • Oligocene-Miocene carbonate platform, reefs on top of pre-existing structural highs. [ABSTRACT FROM AUTHOR]