Abstract: 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.

Key words: deep and ultra-deep formation, high-porosity and high-permeability clastic reservoirs, geological characteristics, formation conditions, accumulation model, Gulf of Mexico Basin

摘要： 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渗碎屑岩储层形成和油气富集的主要原因，其与浮力共同构成深部油气运移的主要动力。盆地北部和南部的沿海平原、陆架和陆坡发育区域性厚层状盐岩层。盐岩变形诱导邻近地层发育一系列断层、形成多种构造圈闭，为深层—超深层油气提供了极好的运移通道和聚集场所。墨西哥湾盆地深层—超深层高孔高渗碎屑岩油气成藏与不均衡压实型超压和区域性厚层状盐岩发育密切相关，表现为"高压驱动、高孔高渗聚集、高点赋存和高位封盖"的成藏模式。被动大陆边缘盆地盐下探区是深层—超深层高孔高渗碎屑岩油气藏的有利发育区和勘探热点区。

关键词: 深层—超深层, 高孔高渗碎屑岩油气藏, 地质特征, 形成条件, 成藏模式, 墨西哥湾盆地