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1、第37卷第1期石油農(nóng)劈弛屆VoJ_37.No.12015年1月PETRoLEUMGEoL0GY&EXPERIMENTJan.,2015文章編號:1001-6112(2015)叭一0064—07doi:10.11781/yydz2015O1064塔河油田奧陶系原油C26降膽甾烷分布特征及地質(zhì)意義李美俊,王鐵冠,張衛(wèi)彪(1.油氣資源與探測國家重點實驗室中國石油大學(北京)地球科學學院北京102249;2.中國石化石油勘探開發(fā)研究院,北京100083)摘要:塔河油田奧陶系原油中都檢測出豐富的C,降膽甾烷系列。大多數(shù)原油24一降膽甾烷含量相對27一降膽甾烷
2、低,而九區(qū)T904和塔東地區(qū)TD2井原油24一降膽甾烷含量相對較高。以LN46、BD2等井為代表的上奧陶統(tǒng)灰?guī)r、泥灰?guī)r具有類似于塔河油田奧陶系原油的C26降膽甾烷分布特征,而以TD2井、和4井及柯坪露頭為代表的寒武系黑色泥巖和灰色灰?guī)r具有類似于T904和TD2井原油的C降膽甾烷分布特征。該文提出判識寒武系烴源層油氣來源的c。降膽甾烷地球化學判識標準為:NCR[24/(24+27)一降膽甾烷J>O.50,NDR[24/(24+27)一降重排膽甾烷]>0.35;上奧陶統(tǒng)烴源層油氣來源的C降膽甾烷判識標準為:NCR<0.40,NDR<0.35。結(jié)果表明C
3、降膽甾烷不僅是塔河油田奧陶系油藏進行原油族群劃分的特征分子標志物,也為研究硅藻、溝鞭藻等藻類的起源和演化以及塔里木盆地古板塊構(gòu)造運動提供了有力的分子地球化學證據(jù)。關(guān)鍵詞:降膽甾烷;硅藻;溝鞭藻;寒武系;塔里木盆地中圖分類號:TEl22.1文獻標識碼:ADistributionofC26norcholestanesinOrdoviciancrudeoilsfromTaheOiifieldanditsgeologicalsignificanceLiMeijun,WangTieguan,ZhangWeibiao(1_StateKeyLaboratoryo
4、fPetroleumResourcesandProspecting,CollegeofGeosciences,ChinaUniversityofPetroleumBeijing102249,China;2.S1NOPECPetroleumExploration&ProductionResearchInstitute,Beijing100083,China)Abstract:AseriesofC,norcholestaneswasdetectedintheOrdoviciancrudeoilsfromtheTaheOilfield,theTarimB
5、asin.northwestChina.Theabundanceof24.norcholestanesinmostoftheOrdoviciancrudeoilswaslowerthanthat0f27一norcholestanes.TheoilsfromwellI)4intheeasternTahe0ilfieldandwellTD2intheeasternTmBasin.however,werecharacterizedbyrelativelyhigher24.norcholestaneabundance.ThedistributionofC,
6、norcholestaneoftheUpperOrdovieianmarlsfromthewellsU、446andBD2resembledthatofthemostOrdoviciancrudeoilsfromtheT£lheOilfield.ThedistributionofC,norcholestanesintypicalCambrianblackshalesandgravlimestonesfromthewellsTD2.He4andoutcropsfromKepingprofileresembledthatofthecrudeoilsfr
7、omthewellsr904andTD2.CriteriaareproposedrelativetoC,norcholestanesthatcouldbeusedtoclassifyoilfamilieswithintheOrdovicianreservoirs.0ilswithNCR(definedas24/(24+27)一norcholestanes)>0.50andNDR(definedas24/(24+27)一nordia—cholestanes)>0.35werethoughttobederivedfromtheCambriansourc
8、erocks.a(chǎn)ndoilswithNCR<0.40andNDR<0.35werethoughttobederivedfr