Research On The Origin Of Oil And Gas In Nanbeier And Tanan Depressions Of Tamuchage Basin

Nanbeier,Tanan depression is Tamuchage Basin's two sub-basin tectonic units,in the Tamuchage basin,eastern Mongolia Chage extend northward into my territory,and belong to one of Hailar Basin tectonic unit.Nanbeier,Tanan depression is an extension of Beier depression,clear Nanbeier,Tanan depression,sources of oil and gas exploration and development of the area not only have a certain significance,but also for improving the theoretical understanding of Tamuchage Basin has some significance.Making a research into the source rock of Nanbeier sag and Tanan sag with comprehensive mark-giving method,the result indicates that nantun group is the source rock of this district,especially special ts strata and n1 of nantun formation are the best stratigrafic position followed by n2 regarded as medium-good which can be seen as the proximate grade,whereas tbm formation,fh formation and dmgh formation are either poor source rocks or not capable of generating hydrocarbon.According to the geological backfround of Tamuchage basin on the basis of experimental analysis with the research on physical properties,group components,carbon isotope composition,saturated hydrocarbon and isoprenoi hydrocarbon characters of crude oil,which is discussed to clarify different types of crude oil according to its enviroment,orgin and maturity.TypeⅠoil of Nanbeier sag is mainly distributed in each layer of northern slope eastern sub-sag.TypeⅡoil is in the fields of fh formation in southern slope eastern sub-sag.TypeⅢoil is primarily generated from n2 of nantun formation in southern slope eastern sub-sag.In addition,typeⅠoil of Tanan sag is mainly found at fh formationin eastern sub-sag,typeⅡoil is found in each layer in middle sub-sag(except for well Ta 19-46),ts strata in eastern sub-sag and n2 of nantun formation. The typeⅢoil is mainly distributed near well Ta 19-46 in the northern part of the middle sub-sag in Tanan sag.It is applied to make a comparison between crude oil and the source rock with gas chromatograph parameters,various biomarkers and carbon isotopic composition,which affirmatively leads to a result that the crude oil mainly comes from the black mudstone of nantun group.TypeⅠoil of Nanbeier originates from the black mudstone of ts strata from the northern slope eastern sub-sag.TypeⅡoil is locally from the ts strata and part of the mudstone of n1 of nantun formation,while typeⅢoil primarily comes from n1 of nantun formation and part of the mudstone in n2 which is of higher maturity,Furthermore,the rest are thought to be from the mudstone of ts strata.TypeⅠoil in Tanan comes from ts strata of this district,and type Ⅱoil is considered to be from the mudstone of ts strata,n1 of nantun formation and part of the n2 of high maturity.TypeⅢoil mostly comes from ts strataand part of the mudstone of n1.