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1、學(xué)兔兔www.xuetutu.com--5天熱氣此第37卷第2期OIL&GASGEOLOGY2016年4月文章編號(hào):0253—9985(2016)02—0205—05doi:10.11743/ogg20160208鄂爾多斯盆地伊盟隆起上古生界天然氣成因及氣源陳敬軼,賈會(huì)沖,李永杰,安川,李巍,劉四洪(中國(guó)石化華北油氣分公司勘探開(kāi)發(fā)研究院,河南鄭州450006)摘要:鄂爾多斯盆地伊盟隆起上古生界天然氣的成因及來(lái)源一直存在爭(zhēng)議。通過(guò)天然氣碳同位素和輕烴綜合分析,6”c,值普遍大于一25.4%o,烷烴氣的碳同位素為正碳同位素系列,甲基環(huán)己烷指數(shù)(MCH)大于50%,具有煤成氣的特征
2、。伊盟隆起上古生界烴源巖以煤為主,什股壕地區(qū)煤層厚度較大,厚度為6~10m,鏡質(zhì)體反射率(R。)為0.8%~1.2%,烴源巖進(jìn)入了大量生烴階段,本區(qū)烴源巖對(duì)天然氣近源成藏具有一定的貢獻(xiàn)。伊盟隆起天然氣甲烷含量平均為94.5%,高于十里加汗地區(qū)平均值91.2%;天然氣8”C。值也明顯高于十里加汗地區(qū),平均數(shù)值相差3%0。由此認(rèn)為天然氣側(cè)向運(yùn)移過(guò)程中發(fā)生了成分色層效應(yīng)和碳同位素分餾作用,伊盟隆起上古生界部分天然氣可能來(lái)自泊爾江海子斷裂以南地區(qū)。關(guān)鍵詞:碳同位素;輕烴;氣源;烴源巖;天然氣;鄂爾多斯盆地中圖分類號(hào):TEl22.1文獻(xiàn)標(biāo)識(shí)碼:AOriginandsourceofnat
3、uralgasintheUpperPaleozoicoftheYimengUplift,OrdosBasinChenJingyi,JiaHuichong,LiYongjie,AnChuan,LiWei,LiuSihong(ExplorationandDevelopmentResearchInstitute,SINOPECNorthChinaCompany,Zhengzhou,Henan450006,China)Abstract:NoconsensushasbeenreachedontheoriginandsourceofnaturalgasintheUpperPaleozoi
4、cofYimengUp-lift,OrdosBasin.Basedonacomprehensiveanalysisofcarbonisotopeandlighthydrocarbon,the8”C2valuesaregene—rallymorethan一25.4%0,alkanecarbonisotopevalueschangeinnormalorderandtherelativecontentofmethylcyclo—hexaneismorethan50%.whichshowthatnaturalgasiscoal—derivedgas.TheUpperPaleozoic
5、sourcerocksinYimengUpliftaredominatedbycoals.InShiguhaoarea,thethicknessofcoalbedsrangesfrom6to10m.Thesourcerockswithavitrinitereflectancefrom0.8%to1.2%reachedthemajorstageofhydrocarbongeneration.Sothelocalsourcerockshaveanimportantcontributiontonear—sourcegasaccumulation.Averagemethanecont
6、entofYimengUpliftis94.5%.whichishigherthanthatofShilijiahanarea(91.2%);8”CvaluewasalossignificantlyheavierthanthatofShilijiahareawiththedifferencevalueof3%o.Itisbelievedthatcomponentdifferentiationandcarbonisotopefractionationoccurredinnaturalgasmigrationprocess.SosomenaturalgasintheUpperPa
7、leozoicofYimengUpliftmaycomefromthesouthofBoerjianghaizifault.Keywords:carbonisotope,lighthydrocarbon,gassource,sourcerock,naturalgas,OrdosBasin伊盟隆起位于鄂爾多斯盆地北部,東西向展布,北等5套地層。主要含氣層位為下石盒子組3段(盒3與河套地塹相鄰,南以伊陜斜坡北部三眼井一泊爾江段)、盒2段、盒1段和山西組1段(山1段)。圈閉類海子斷裂為界,西起烏加廟,東至托克