The Geochemical Characteristics And Accumulation Period Of Oil And Gas In The North Shuntuoguole Of Tarim Basin

In order to achieve new results in exploration,deepen the deep hydrocarbon accumulation mechanism of the Ordovician in the north of Shuntuoguole area,predict favorable oil and gas exploration target areas and improve the exploration success rate.Conducted geochemical comparative studies on oil and gas fields in and around the north of Shuntuoguole area,evaluated oil and gas maturity,studied crude oil groups and oil sources,and determined the sub-storage period of oil and gas reservoirs.This paper mainly focuses on the Ordovician oil and gas reservoirs of different fault zones in the Shuntuogule low-uplift of the Tarim Basin,and analyzes characteristics of the Ordovician volatile oil,light oil and natural gas.Through the combination of macrogeology and microgeochemical analysis,the geochemical characteristics of crude oil and natural gas are studied by using oil and gas properties,light hydrocarbons,saturated hydrocarbons,aromatic hydrocarbons,carbon isotope and other parameters.On the base of the geochemical characteristics of oils,the oil-source and gas–correlation were carried out.Through analyzing homogeneous temperature of fluid inclusion,with heat history and buried history,main accumulation period of the Ordovician oil and gas reservoirs in the north Shuntuoguole was claimed.This paper shows that the hydrocarbon-generating parent materials of the Ordovician crude oil and natural gas in different fault zones in the north of the north Shuntuoguole are marine I-II₁kerogen,and the hydrocarbon-forming parent material is mainly marine algae.The hydrocarbon maturity of the Ordovician in different fault zones in the north Shuntuoguole gradually decreases from east to west.The maturity of different wells in the No.1 fault zone is similar,which is basically in the stage of high-over maturity,and the smoothness of the north Shuntuoguole No.7 fault zone.The SHB7 well is basically a mature stage.The oil and gas in the north Shuntuoguole are comparable to the source rocks of the Yuertusi Formation of Cambrian.There may be at least two periods of oil and gas filling or accumulation in the north Shuntuoguole.The early stage of filling the crude oil has a low maturity,and the late stage oil and gas filling is mainly composed of light oil with high maturity and associated gas.The Ordovician deep oil and gas reservoirs in the north Shuntuoguole have certain exploration potential.