准噶尔盆地腹部超压层分布与油气成藏的关系

eep zone overpressure system is commonly developed in the central part of Junggar Basin (deeper than 4000 meters) and many drillings met the overpressure zone. The analysis of drilling, geology, logging, and seismic data in the overpressure section shows that the overpressure zone is characterized by the overpressure response of high acoustic travel time, low resistivity, and low seismic velocity. The depth of overpressure stratums in the central part of Junggar Basin differs in different sags, with the West Pen1 Well sag being shallowest (4000-7000m), the North Dongdaohaizi sag and the east part of Changji Sag being the second shallowest (5000-9000m), and the center and west of Changji sag the deepest (6000-10000m). Most of the overpressure stratums are along-bed distributed, except the margin area of the sag and some local areas in the sag where layer penetration can be found. The stratums distributed on the top of overpressure become shallow from north to south, from east to west, and from the top of Triassic to the bottom of Cretaceous. As probably hydrocarbon-originated and post-diagenesis-stage overpressure in the central part of Junggar Basin, most volumes of hydrocarbon accumulates around the top overpressure surface, deep overpressure is driving force of hydrocarbon migration, and overpressure stratums distribution controls the formation of secondary porosity zone and accumulation of hydrocarbon.