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三叠系是鄂尔多斯盆地油气勘探的主要目的层之一,其储集层以低孔低渗-特低渗为特点。由于受到后期构造作用的影响,使得延长组的储层中裂缝比较发育。通过野外地质调查分析,认为裂缝可以分为构造裂缝、成岩裂缝、构造成岩裂缝和异常高压成因裂缝四种类型,研究的结果表明,姬塬-元城地区的的45口探井中有25口井的视密度是小于0.1条/m,占总井数的55.6%,就所有的岩心样品来看,视密度小于0.1条/m的样品占总数的90%左右,说明了该区的裂缝不是很发育,裂缝的开度大都小于0.5 mm,其中开度为0～0.5 mm的裂缝占总样品数的接近74%,22.6%的裂缝是闭合的。研究区的裂缝多数被充填,占总数的81%,其中半数以上的充填物为方解石。
Triassic is one of the main hydrocarbon reservoirs in the Ordos Basin. Its reservoirs are characterized by low porosity and low permeability - extra low permeability. Due to the influence of the late tectonic setting, the fractures in the extended reservoirs are relatively developed. According to field geological survey and analysis, the authors believe that the fractures can be divided into four types: structural fractures, diagenetic fractures, structural diagenetic fractures and abnormal high-pressure fractures. The results show that there are 25 wells in 45 exploration wells in the Jiyuan-Yuancheng area The apparent density is less than 0.1 / m, accounting for 55.6% of the total wells. For all core samples, the apparent density less than 0.1 / m accounted for about 90% of the total, indicating that the area is not very crack Development and crack opening are mostly less than 0.5 mm, of which the cracks with the opening of 0 ~ 0.5 mm accounted for nearly 74% of the total samples, and 22.6% of the cracks were closed. Most of the cracks in the study area were filled, accounting for 81% of the total, of which more than half of the fillings were calcite.