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以鄂尔多斯盆地东北缘地区本溪组—山西组菱铁质泥岩为研究对象,对研究区钻孔岩心与测井资料采用逻辑判别、蛛网图等方法,量化了研究区菱铁质泥岩的测井识别特征,建立其测井识别模板。研究表明,菱铁质泥岩具有高光电吸收截面指数(PE)、高密度(DEN)、高自然伽马(GR)、低声波时差(AC)、低电阻率(M2RX)、低中子孔隙度(CNCF)的特征,研究区12口钻孔中的菱铁质泥岩识别结果表明,总厚度为3.9~25.4m,总层数为8~28层,区域分布不均;通过测井资料定量分析了菱铁质泥岩的物性及封盖性能,指出研究区菱铁质泥岩具低孔低渗性及高突破压力的特点,其平均渗透率为2.29×10~(-8)μm~2、平均有效孔隙度为1.20%、平均突破压力为12.32MPa,在叠置含气系统中具备隔水阻气性能。基于菱铁质泥岩的空间发育位置,沉积环境及形成过程分析,在本溪组山西组共识别出4个稳定隔水阻气层,结合气测资料将研究区本溪组—山西组垂向划分出5个独立含气系统,每个独立含气系统的边界便是区域分布稳定、连续性好且垂向发育具有一定规模的以菱铁质泥岩为主要岩层的隔层。
Taking the Benxi Formation-Shanxi Formation siderite mudstone in the northeastern margin of the Ordos Basin as the research object, Logging core data and log data in the study area were quantified by logistic discrimination and cobweb mapping to identify the logging identification of siderite mudstone in the study area Feature, build its log identification template. Studies have shown that the siderite mudstone has high PE, DEN, GR, AC, M2RX, low neutron porosity (CNCF). The recognition results of siderite mudstone in 12 boreholes in the study area show that the total thickness is 3.9 ~ 25.4m, the total number of layers is 8 ~ 28 layers, and the area is unevenly distributed. The logging data The properties and capping properties of rhombic mudstone are analyzed. The characteristics of rhombic mudstone with low porosity and permeability and high breakthrough pressure are pointed out. The average permeability is 2.29 × 10 ~ (-8) μm ~ 2, The average effective porosity is 1.20%, and the average breakthrough pressure is 12.32MPa, which has the property of water blocking and gas barrier in the stacked gas system. Based on the analysis of the spatial distribution, depositional environment and formation process of siderite mudstone, four stable water-resisting gas-barrier layers were identified in the Shanxi Formation of Benxi Formation. According to the gas-measure data, the Benxi Formation-Shanxi Formation was vertically divided Five independent gas-bearing systems, the boundaries of each independent gas-bearing system are compartments with stable distribution, good continuity and a certain vertical scale with rhomitic mudstone as the main rock formation.