Shale Geochemical Characteristics And The Study Of Organic Facies In SuiDe Of The Ordos Basin

With the increasingly prominent contradiction between supply and demand of energy,the exploration and development fields of oil and gas gradually towards the direction of coalbed methane,shale gas,gas in tight sand and other unconventional oil and gas development.The study of unconventional oil and gas also gradually in-depth comprehensive.This paper uses organic geochemical,sedimentology and logging geology theory methods to do geochemical characteristics research and systemic research on the organic facies about shanxi formation in SuiDe region of Ordos Basin,then have a preliminary division about the organic facies in research area of shanxi formation.The research area have abundant of high organic matters,average TOC is around 4%;The mainly organic matter type is type II and type ?.Organic matter evolution degree is high,Ro averaged 1.54%,belong to mature to over mature stage.The TOC value in Shan2 section is significantly higher than Shan1 section,including Shan2 mud shale interval thickness interval with high TOC is more than 2%.TOC content and explores the shale reservoir porosity logging evaluation method research,established the equivalent saturation point and consider dry,wet clay triangle method is suitable for the continental shale-sea-land transition phase evaluation of log interpretation method.The climate of the Suide region is humid.Shan2 period of depositional environment or affected by the Marine environment,environment of the sea and land.Shan 1 section for brackish water environment,less affected by the sea.The main atmosphere of Shanxi formation is poor-oxygen atmosphere,high underground water level,or near sea level attachments,are greatly influenced by the water,local rapid accumulation of such as peat flat and swamps may develop anaerobic environment,makes the organic matter preserved.Through the analysis of core observation and well logging data in the study area,the study area of Shanxi formation shale can be subdivided of 7 kinds of lithofacies types:(deep)grey shale,(deep)grey sandy shale,(deep)containing carbonaceous shale,gray(ash)containing the carbon black sandy shale,(ash)of black carbonaceous shale,(ash)black carbonaceous shale and calcium shale.The Shan1 section mainly belong to river deposition,Shan2 section mainly belong to delta plain deposits.Through useing the advanced geochemical analysis testing techniques and analysis methods in the study area,including: organic carbon testing,sporopollen analysis comprehensive evaluation of Shanxi formation in the study area about the shale organic matter characteristics,sedimentary environment differences and the differences of preservation condition,Shan1 section is divided into river stranded,point bar,crevasse-splays,natural levees,rich plant swamp,poor plant,peat swamp ping and HeJian depressions organic facies;Shan2 section is divided into crevasse-splays,natural levees,rich plant swamp,lean,split between depressions and peat swamp ping organic phase.Among them,the rich plant swamp TOC is the highest,followed by poor plant swamp,shunt between depressions and HeJian depressions are relatively poor,and Shan2 have a rich development of rich plant swamp,poor plant swamp developed in both Shan1 formation and Shan 2 formation.