基于多参数评价的致密砂岩气藏成岩相定量划分——以鄂尔多斯盆地神木气田山_1段储层为例

为探讨致密砂岩气藏成岩相的定量划分方法,以鄂尔多斯盆地神木气田山1段储层为例,综合利用多种测试结果和测井资料对成岩作用类型、成岩作用强度和成岩相进行了分析评价。根据成岩和测井参数建立了成岩相划分标准,阐述了不同成岩相的基本特征。研究区山1段储层发育溶蚀孔、晶间孔和少量粒间孔,压实程度中等为主,局部发育弱和强压实,胶结程度中等为主,含少量弱和强胶结,溶解程度中等—强。依据成岩作用强度、胶结类型和孔隙类型,可划分出5种成岩相,基于自然伽马、深侧向电阻率、声波时差和密度资料建立的测井参数划分标准可对成岩相进行有效识别。成岩相与沉积微相之间存在良好的对应关系,优势沉积微相控制有利成岩相分布。不同成岩相的特征存在明显差异,分布于三角洲平原分流河道微相的中等压实伊利石、绿泥石胶结—溶蚀孔+粒间孔相和中等压实伊利石、高岭石胶结—溶蚀孔+晶间孔相是研究区的有利成岩相带。

Quantitative classification of diagenetic facies in tight sandstone gas reservoirs based on multi-parameter evaluation:A case study of the first member of Shanxi Formation in the Shenmu Gas Field,Ordos Basin

Diagenesis types, intensity and facies were evaluated using a variety of laboratoryresults and logging data in order to explore the quantitative classification method of diagenetic facies in tight sandstone gas reservoirs. Diagenetic facies classification standardswere established based on diagenesis and logging parameters. The basic characteristics of different diagenetic facies were elaborated taking the first member of Shanxi Formation in the Shenmu Gas Field in the Ordos Basin as an example.Dissolved pores, intercrystalline pores and small amounts of intergranular pores developed in the first member of Shanxi Formation in the study area. The formation is characterizedby medium compaction (locally weak or strong compaction), medium cementation (locally weak or strong cementation), and medium to strong dissolution. Five diagenetic facies weredefinedaccording to diagenesis intensity, cementation and pore types.Furthermore, diagenetic facies could be effectively recognized based on natural gamma ray logging, deep lateral resistivity logging, density logging and acoustic logging.The distribution of favorable diagenetic facies was controlled by advantageous sedimentary microfacies. Obvious differences appear among different diagenetic facies. Moderate compaction illite, dissolution pore+intergranular pore facies with eitherchloriteor kaolinite cementation, distributed in distributary channel microfacies of delta plains are favorable diagenetic facies in the study area.