通过对鄂尔多斯盆地麻黄山西区块长8油组岩心观察,以及综合运用普通薄片、铸体薄片、扫描电镜以及压汞等分析化验资料,在对储层成岩作用类型和特征研究的基础上,结合孔渗条件,将该区目的层段成岩相划分为四类;再结合各类成岩相电测响应特征,建立成岩相测井识别标准,完成各单井成岩相识别;在此基础上对井间成岩相的空间展布状态进行预测,并对各类成岩相发育规律进行分析、总结.研究表明,麻黄山西区块长8油组储层划分为斑状溶蚀孔隙成岩相、碳酸盐致密胶结成岩相、黏土矿物致密胶结成岩相和致密压实成岩相四种成岩相类型.斑状溶蚀孔隙成岩相主要发育在水下分流河道微相中,物性最好,横向延展性和连通性好;黏土矿物致密胶结成岩相和碳酸盐致密胶结成岩相主要发育在水下分流河道、席状砂、河口坝微相中,物性次之;致密压实成岩相主要发育在分流间湾微相和前三角洲泥微相,物性最差,连片发育,为本区最发育的成岩相类型.体现优质成岩相主要发育在优势沉积微相中,成岩相对孔渗具有控制作用.斑状溶蚀孔隙成岩相碳酸盐致密胶结成岩相中试油日产和单位产能最高,是最有利于油气富集、开采的优势相带,为下一步重点开发的区域;黏土矿物致密胶结成岩相和致密压实成岩相虽然分布范围广,但整体产能较低,分析认为主要由于这两类相带物性较差,在生产开发中应采取酸化、压裂等方式进行储层改造来提高产能.%The study is focuses on the Chang 8 formation in west area of Mahuangshan,Ordos Basin.The analysis is based on the data collated from cores,thin sections,casting thin sections,scanning electron microscopy (SEM) and mercury intrusions.In order to study the reservoirs' diagenetic facies,firstly,the type of diagenesis and its characteristics should be ascertained.Secondly,based on the combined porosity and permeability data,the Chang 8 formation was segregated into four types of diagenetic facies.Thirdly,based on the logging response characteristics of the diagenesis,the logging identification standard of the diagenetic facies was established and used in the diagenetic facies identification of the wells.Finally,based on the results of the above study,the distribution of diagenetic facies between wells can be predicted,and the development regularities of the diagenetic facies summarized.From the study,the diagenetic facies of the Chang 8 formation in the west of Mahuangshan area can be divided into four types,which are porphyritic corroded porosity diagenetic facies,carbonate cemented tight diagenetic facies,clay minerals cemented tight diagenetic facies and compacted tight diagenetic facies.The porphyritic corroded porosity diagenetic facies mainly developed in an underwater distributary channel microfacies,possessing the most excellent properties such as,transverse ductility and connectivity.Carbonate cemented tight diagenetic facies and clay minerals cemented tight diagenetic facies mainly developed in an underwater distributary channel,sheet sand,debouch bar microfacies,possessing the second physical property.Compacted tight diagenetic facies mainly developed in a distributary bay microfacies and pre-delta mud microfacies,possessing the third physical properties also with continuous development characteristics,which happens to be the most well developed diagenetic facies type in the study area.High quality diagenetic facies had mainly developed in an advantageous sedimentary microfacies,which possessed a controlling function on porosity and permeability.Porphyritic corroded porosity diagenetic facies had the highest testing of oil daily production and unit productivity rates,which is the most suitable diagenetic facies of the most conducive to the enrichment and exploitation of oil and gas,and simultaneously is the key development area for next step.Clay minerals cemented tight diagenetic facies and compacted tight diagenetic facies however possess a wide distribution,but with a low production rate,which is mainly due to its poor physical properties.For improved productivity,acidification and fracturing always be taken into consideration in order to modify the reservoir into two types of diagenetic facies.
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