鄂尔多斯盆地陇东地区延长组储层定量成岩相研究

应用铸体薄片、阴极发光、扫描电镜等资料,对陇东地区延长组储层成岩作用类型及定量强度进行了综合研究,用定量指标划分成岩相类型,建立了不同类型成岩相测井响应特征模板,并对成岩相纵向及平面分布进行了研究。压实、胶结、溶解3种主控成岩作用的强度计算与分级研究表明,研究区压实作用较强,主要为强压实、中压实,在粒度较细、杂基含量较高的砂岩中可达到极强压实;胶结作用强度差异较大,以弱胶结为主,局部地区发育强胶结;溶解作用强度较大,以中溶解、强溶解为主。成岩相类型可划分为中压实强溶解相、中压实中溶解相、中压实中胶结中溶解相、中压实强胶结相、强压实强溶解相、强压实中溶解相、强压实强胶结相、极强压实相8种成岩相类型。相对优质储集相(中压实中强溶解相和强压实强溶解相)在纵向上主要分布在长3油层组和长8油层组,平面上不同油层组相对优质储集相分布区存在差异,主要呈条带状和透镜状分布。

Research on quantitative diagenetic facies of the Yanchang Formation in Longdong Area, Ordos Basin

Based on data of cast thin section,cathodoluminescence and scanning electron microscope,the present paper comprehensively investigated the types and quantitative intensity of reservoir diagenesis of the Upper Triassic Yanchang Formation in Longdong Area of Ordos Basin,distinguished the types of diagenetic facies with the aspect of quantitative index and researched the vertical and horizontal distributions of diagenetic facies.The intensity calculation and classification of compaction,cementation and dissolution indicated that the Yanchang Formation of Longdong Area underwent strong compaction including medium to strong compaction and extremely strong compaction locally for the high contents of matrix.There is a great difference in cementation intensity which presents mainly in weak cementation with local medium to strong cementation.Dissolution is strong in the study area mainly in medium to strong.The reservoir could be divided into eight types of diagenetic facies,including medium compaction with strong dissolution facies,medium compaction with medium dissolution facies,medium compaction with medium cementation and medium dissolution facies,strong compaction with strong dissolution facies,strong compaction with medium dissolution facies,medium compaction with strong cementation facies,strong compaction with strong cementation facies and extremely strong compaction facies.Relatively high quality reservoir which presents as medium compaction with medium dissolution facies,medium compaction with strong dissolution facies,medium compaction with medium cementation and medium dissolution facies and strong compaction with strong dissolution facies are mainly distributed in Chang 3 and Chang 8 reservoir.Horizontally,the distribution of relatively high quality reservoir differs in different oil-bearing formation mainly shaped in ribbon and lentoid.