墨西哥湾盆地深水区油气成藏条件及勘探方向OA

To further understand the hydrocarbon accumulation rules of the deepwater Gulf of Mexico Basin,using the seismic,drilling and geochemical test data of the study area,the tectonic-sedimentary evolution characteristics and the accumulation conditions are systematically analyzed,and the hydrocarbon accumulation model and exploration direction are discussed.The oil and gas exploration are mainly concentrated in four major geological regions,namely,basin,sub-salt,folded belt and abyssal plain,which is the result of the complex interaction between sedimentation and tectonics in Mesozoic and Cenozoic.The ma-rine marlstones of the Upper Jurassic Tithonian and Oxford Stages are the main hydrocarbon source rocks in the deep-water area,showing the characteristics of"deep burial","old age"and"late hydrocarbon generation".The reservoirs are of various types,and generally show the characteristics of"multi-layer system","new age","fast burial"and"high pore permeability".The penetrating transportation channels associated with salt rock movement and accompanying fault activity are crucial for oil and gas transportation.There are three types of deep-water tectonic circles:structural traps with four-way closures,combined structural/stratigraphic traps with three-way closures,and stratigraphic traps.To sum up,three reservoir-forming combination models were formed,which are"early source fault communication—late fault or salt-body flanking closure—high level accu-mulation","subsalt overpressure and low temperature—fault communication—salt-body/salt-welding occlusion accumulation"and"near-source vertical migration—lateral transport adjustment—dominant structure accumulation".The Wilcox sandstones in sub-salt and folded belt,Jurassic aeolian sandstones in the eastern basin and abyssal plain are favorable exploration targets in the deepwater Gulf of Mexico Basin.