CAJ | 학술논문

鄂尔多斯盆地西南部镇泾地区延长组长8油层组是典型的致密砂岩储层，具有低孔低渗的特点。通过对其20余口井的岩心观测、测井和录井分析，结合显微镜、铸体薄片及电子显微镜观察等手段，配合储层岩石学、沉积学的分析，认为镇泾地区D工区砂岩以岩屑长石砂岩为主，并且含有少量的长石岩屑砂岩。沉积相以辫状河三角洲亚相为主，其中以水下分流河道微相储层物性最好，可提供最有利的油气聚集空间，河口坝微相物性次之，亦可作为储层的有利区域。通过分析储集物性与砂岩粒度之间的关系，认为中砂岩具有最好的储集物性。通过对研究区成岩机理的研究，认为影响砂岩储层的主要成岩作用为压实作用、胶结作用以及溶蚀作用。压实作用为破坏性的成岩作用，使该区砂岩储层的孔隙度和渗透率减少，埋深2400 m以上孔隙度小于10％；胶结作用具有正反两个方面的成岩作用，既可通过胶结物的生成减少岩石的孔隙，又可通过抑制压实作用的进一步进行从而保持颗粒间的距离；溶蚀作用为建设性的成岩作用，尤其是深部储层中两期溶蚀作用的发生，使孔隙度得以改善，从而使油气的储集和运移变得更加有利。
악이다사분지서남부진경지구연장조장8유층조시전형적치밀사암저층，구유저공저삼적특점。통과대기20여구정적암심관측、측정화록정분석，결합현미경、주체박편급전자현미경관찰등수단，배합저층암석학、침적학적분석，인위진경지구D공구사암이암설장석사암위주，병차함유소량적장석암설사암。침적상이변상하삼각주아상위주，기중이수하분류하도미상저층물성최호，가제공최유리적유기취집공간，하구패미상물성차지，역가작위저층적유리구역。통과분석저집물성여사암립도지간적관계，인위중사암구유최호적저집물성。통과대연구구성암궤리적연구，인위영향사암저층적주요성암작용위압실작용、효결작용이급용식작용。압실작용위파배성적성암작용，사해구사암저층적공극도화삼투솔감소，매심2400 m이상공극도소우10％；효결작용구유정반량개방면적성암작용，기가통과효결물적생성감소암석적공극，우가통과억제압실작용적진일보진행종이보지과립간적거리；용식작용위건설성적성암작용，우기시심부저층중량기용식작용적발생，사공극도득이개선，종이사유기적저집화운이변득경가유리。
The Yanchang Formation in Zhenjing area , southwestern Ordos Basin , contains typical low-porosity and low-permeability tight sandstone reservoirs .Core observation and logging data analyses of more than 20 wells drilled in the reservoirs were combined with experimental means like microscope and scanning electronic microscope to study the litho -logy and sedimentology of the reservoirs .Results show that the rocks are mainly lithic ~arkoses with small amount of feld-spathic litharenites .Sedimentary facies are dominated by the subfacie of braided fluvial delta ,of which the microfacies-un-derwater distributary channel and mouth bar-have the best and second best petrophysical properties for hydrocarbon poo -ling.Analyses of relationship between reservoir physical properties and grain size of sandstone indicate that sandstone is the best in terms of reservoir physical properties .Diagenesis study of the area shows that three factors had played critical roles , namely compaction ,cementation and dissolution .Compaction caused porosity ( and permeability ) of the rocks to decrease to less than 10%at a depth deeper than 2 400 m.Cementation was both destructive and constructive in that it reduced porosity of the rocks but meanwhile it also restrained further compaction and kept the particles apart .Dissolution was favorable for reservoir physical properties as the porosity was greatly improved during two stages of dissolution in deep reservoirs .