The Analysis Of Petroleum Accumulation Geological Conditions In HuHe Depression Of HeTao Basin

Under the guidance of petroleum geology theory, this paper makes full use of the geophysical well logging, seismic, magnetic, logging, outcrop survey and experimental test analysis, and based on the analysis of regional geological background and predecessors’ research results, through researching the strata, sedimentary and tectonic research and other basic geological characteristics, this paper focuses on the research of hydrocarbon accumulation conditions and mechanism in Quaternary system and Pliocene Series, such as Hydrocarbon source rocks, reservoir and cover, looking for trap and favorable prediction in Hu He depression of He Tao basin.The research suggests that He Tao basin is Cenozoic down-faulted basin, deep in north and shallow in south, asymmetry structure, the Hu He depression is the second largest depression zone. The sedimentary strata mainly include: lower Cretaceous, Eocene, Oligocene and Miocene, Pliocene Series and Quaternary system. The formation and development of He Tao basin mainly experienced Yanshan and Himalayan tectonic movement. Since late Cretaceous, the basin began to rift subsidence because of shear-tension, the basin entered the stage of evolution. It is not continued to sink, it has the pulse and shock characteristic of sedimentation-stop-uplift-settling again-stop-uplift, since late Pleistocene with "basin-coupling effect".The sedimentary facies of Quaternary system and Pliocene Series in Hu He坳陷mainly includes half deep lacustrine,shallow lacustrine,shore and shallow lake,lakeside.The zone has high organic abundance,strong generation capability and good kerogen types;the performance of reservoir porosity and permeability is superior;the large and stable distribution of Glauber’s salt layer and Argillaceous rock is good regional cover;Stratigraphic sequence and lithologic combination favorable space configuration of Hydrocarbon source rocks,reservoir and cover for the gas reservoir formation.Through the research of strata,structure,sedimentary facies and the comprehensive analysis of oil and gas geological characteristics,predicted three exploration area:one is between the Tu You Qi and Da Cheng Xi,the area is about 300Km2,the other two locate in the Ha Su-Ta Bu Sa-Bi Ke Qi and the eastern Xin Ying Zi,the area is about 350Km2 and 350Km2.