深层—超深层高孔高渗碎屑岩油气藏地质特征、形成条件及成藏模式——以墨西哥湾盆地为例

深层与超深层作为当前墨西哥湾盆地油气勘探的热点领域,具有巨大的油气资源潜力,分析深层—超深层油气藏的地质特征、形成条件及其成藏模式对于明确深层—超深层油气藏的分布规律具有重要意义.与中层—浅层相比,墨西哥湾盆地深层—超深层具有较低的地温梯度和较高的压力梯度,发育大量高孔高渗碎屑岩油气藏.不均衡压实成因型超压是深部高孔高...

Geological characteristics,formation conditions and accumulation model of deep and ultra-deep,high-porosity and high-permeability clastic reservoirs: a case study of Gulf of Mexico Basin

As the hotspots for oil and gas exploration in the Gulf of Mexico, deep and ultra-deep formations have huge oil and gas resource potential. To analyze the geological characteristics, formation conditions and accumulation mode of deep-ultra-deep oil and gas reservoirs is crucial for clarifying the distribution law of deep -ultra-deep oil and gas reservoirs. Compared with the middle-shallow formations, the deep-ultra-deep formations in the Gulf of Mexico Basin have lower geothermal gradients and higher pressure gradients, with the development of plenty of high-porosity and high-permeability clastic reservoirs. Overpressure due to disequilibrium compaction is the main reason for the formation of deep high-porosity and high-permeability clastic reservoirs as well as oil and gas accumulation. Together with buoyancy, they constitute the main driving force for deep oil and gas migration. Thick-layered salt rock is developed in regional areas of the coastal plains, continental shelf and continental slope in the north and south of the basin. Salt rock deformation induces the development of a series of faults in adjacent strata and forms a variety of structural traps, providing excellent migration pathways and accumulation sites for deep and ultra-deep oil and gas. The hydrocarbon accumulation in the deep-ultra-deep, high-porosity and high-permeability clastic rock in the Gulf of Mexico Basin is closely related to the overpressure due to disequilibrium compaction and the development of regional thick-layered salt rock, showing the accumulation model of "hydrocarbons driven by high pressures, accumulating in high-porosity and high-permeability reservoirs, storing at high point of traps and sealed by overlying cap rocks". Deep-ultra-deep, high-porosity and high-permeability clastic oil and gas reservoirs are prone to be developed in pre-salt layers of the passive continental margin basins, which can become the hot spots for the exploration of deep-ultra-deep, high-porosity and high-permeability clastic reservoirs.