Petroleum Geological Characteristics And Resource Potential In Northern Xianyang, Shaanxi

Ordos Basin is the second largest sedimentary basin in China,contains the rich oil and gas resources.During nearly a hundred years of effort,the exploration and development of the whole Ordos Basin has made remarkable achievements,but on the whole, the degree of central and northern basin oil and gas exploration and development is higher,the southern margin of the basin exploration and development relative lag. Xunyi exploration area of Yanchang oilfield is located close to the Weibei rise of Ordos Basin in the East and the west, years of exploration and development,oil and gas extraction in the region is unsatisfactory,strengthen the research on oil and gas geological characteristics and the resource potential evaluation and to guide further oil and gas exploration and development has(have) important practical significance.In this paper,on the basis of field investigation,with guidance of sedimentology, tectonics and petroleum geology theory,combining previous research results,through field investigation and indoor comprehensive analysis,determine the formation characteristics, tectonic features and sedimentary characteristics of Xunyi exploration area,on this basis, combining with testing and analysis data,analysis hydrocarbon source rocks, reservoir formation and oil gas reservoir and gas forming condition of the Xunyi exploration area,at last,with analogy method to estimatenXunYi exploration area of geological resources.The main achievements of this research:(1)most of Yanchang formation in the western Xunyi exploration area is generally lack of Chang 4+5 formation,the eastern region has a relatively complete stratigraphic development,overall structure pattern is“South and East higher,North and West lower,”there are mainly two underwater channel sand body of southwest provenance;(2)Through the study of the reservoir,it is believed that the formation of the reservoir rocks in this area is relatively low in mineral maturity, and the structure has a high maturity,lithology is mainly composed of feldspar sandstone;(3)Through the comprehensive evaluation of the hydrocarbon source rocks characteristics in Xunyi exploration area,it is believed that the organic matter abundance of source rocks in this area is high, and the type of organic matter is mainly type I and type II,the minority is close to type III, and the organic matter generally reaches the mature stage;(4)The main reservoir type ofXunyi exploration area is dominated by lithologic reservoir or structural lithologic composite reservoir,the main controlling factors of oil and gas reservoir formation are high quality source rock,effective reservoir sand body and abnormal high pressure;(5)By analogy to preliminary estimation of geological resources in the Xunyi area is 5345×104t.