Oil And Gas Geochemical Characteristics Analysis Of Dishuiquan Area In Junggar Basin

Dishuiquan area lies in the Luliang uplift in the east of Junggar basin, and is asecondary tectonic unit of the Luliang uplift. It east Carat beautiful mountain and isbordered by Wucaiwan Dongdaohaizi depression in the south, and the Dishuiquandepression in the West. It’s a nose structure with east-west strike.On the basis of the fielddataand the analysis of experimental data,Geochemicalcharacteristics of Source rocks,oiland gas in studying area wereanalyzedbyCombination with the geological backgroundofDiShuiquanarea in Junggar Basin.In the paper,we study the abundance of organic matter in source rocks, type andmaturity and characteristics of biomarkers;then analysis the oil propertiesand familycomposition,characteristics of carbon isotopic and biomarkers organic source.maturity and characteristics of biomarkers; also analysis the Component of gas andcharacteristics of biomarkers in gas.Through above researches, the property andSedimentaryenvironment of source rock,organicsource havebeendiscussed.Dishuiquan area source rocks mainly has four layers, every layers all have a highorganic carbon content, the Jurassic coal strata’s TOC content reaches at14.53%,which was still in the stage of immature to low mature. Carboniferous and Permian’sTOC content are respectively2.36%and1.78%.They are both good hydrocarbonsource rocks.Triassiccontent of organic carbon is0.82%, reaching hydrocarbonstandards,while because of chloroform bitumen "A" and hydrocarbon generationpotential were respectively only0.0295%and0.95mg/g. Therefore Itis relativelypoor source rocks.The lithology of source rockhas littleeffect on its organic mattercontent,For the same well, the dark mudstone organic carbon content is higher thanthe tuff.Type of organic matteris III,But overall the upper and lower Carboniferoussource rocks are better than the Upper Carboniferous.The distributionofCarboniferous and Permian mudstone C27、C28、C29steranesare presented reversed“L”and the font of“厂”.In the east of Dinan bulge of the work zone, the crude oil has high density, up to 0.87～0.91grams per cubic centimeter. It belongs to low middle condensated and waxoil. In the middle of Dinan bulge the density of the crude oil is inferior to the eastapparently. The isotope value of the crude oil deeply(Carboniferous) in the east is-24.92‰, and is similar to the source rocks of the typical Carboniferous humus typein the Wucaiwan-Dongdaohaizi, middle-shallow layer is similar to the crude oil withsource of Permian, it’s-30.74‰, considering the mature characters, the maturity ofthe crude oil in this area is higher than that of the hydrocarbon source rocks in thisarea, and it should come from the deeper depression of the Permian source rocks ofDongdaohaizi depression. The isotope value of the crude oil in the south boundary ofthe middle section is-28.43‰, the isoheptane value of crude oil lies in1.25～2.06,and it is similar to Lunan number one well(Permian), considering the distributioncharacter of the Pr/Ph, we know the south boundary of the middle section crude oil ismainly supplied by Permian and Jurassic source rocks, and Permian takes up the vastmajority. In the crude oil from the east section, the distribution of C27、C28、C29（20R）regular gonane is mainly shaped as “/”,the distribution of C20、C21、C23tricyclicditerpane is shaped as mountain peak, the content of gammacerane lies in0.16～0.26,organic sedimentation water is inclined to oxydic. In the Jurassic crude oil from thesouth boundary of the middle section,C27、C28、C29(20R) regular gonane is shaped asreverse “L”, the content of the tricyclic diterpane is in the sequence of C19＞C20＞C21＞C23, and the crude oil does not contain gammacerane. In the Cretaceous crude oil,C27、C28、C29(20R) regular gonane is shaped as “厂”, tricyclic diterpane is mainly C20、C21、C23，and is distributed as asymmetric mountain peak, the average content ofgammacerane is up to0.36, organic sedimentary water is strong reductive.The aridity coefficient of the natural gas in the east of Dinan bulgereaches0.96.which belongs to the dry gas，methane carbon isotope is lighter，which maybe theproduct of humus type organic matter source. in a word，this is the result of the mix ofpostmature natural gas and native crude oil degraded by bacteria.A majority of thosenatural gas aridity coefficient in the middle of Dinan bulge’s north and south branch isabove0.9,mainly belong to dry gas,and the methane and ethane’s carbon isotope aregenerally wighter,which have the characteristic of postmatrue product of humic typesource,and consistent with the source of carboniferous gas.