关键词: 准噶尔盆地, 超压层分布, 油气成藏, 输导体系, 储集空间

Abstract: The deep zone overpressure system is commonly developed in the central part of Junggar Basin (deeper than 4000 meters). The analyses of drilling, geology, logging and seismic data of the overpressure section show 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 strata in the central part of Junggar Basin differs in different sags. The western sag of Pen 1 Well has the depth from 4 kilometers to 7 kilometers, and the northern sag of Dongdaohaizi area and the east part of Changji Sag have the depth from 5 kilometers to 9 kilometers, and the center and west parts of Changji Sag have the depth from 6 kilometers to 10 kilometers. Most of the overpressure system were distributed along bed, and layer penetration could be found in the margin area and some local areas of the sag. The top of overpressure strata distribution are getting shallow from north to south and from east to west. Those strata transferred from the top of the Triassic to the bottom of the Cretaceous. As probably hydrocarbon-originated and post-diagenesis-stage overpressure in the central part of Junggar Basin, oil and gas were mainly accumulated around the top of overpressure strata. The deep overpressure was the driving force of hydrocarbon migration. The distribution of overpressure strata controlled the formation of secondary porosity zone and accumulation of hydrocarbon.

Key words: Junggar Basin, overpressure stratum distribution, hydrocarbon accumulation, conducting system, reservoir space