【摘要】 鄂尔多斯盆地华庆地区上三叠统延长组长63油层组属于特低渗储层,裂缝发育、分布情况及裂缝的有效性已成为制约油气有效勘探开发的瓶颈之一。以统计法为基础,综合应用岩石破裂法和能量法,以非均质性储层有限元应力场模拟为手段,对华庆地区长63储层天然裂缝发育程度和分布进行了定量化预测研究,同时结合定向岩心、薄片裂缝定量观测结果,主要依据裂缝方位、间距和密度等特征参数,初步建立了长63储层天然裂缝分布网络概念模型;该模型描述了储层裂缝发育基本状况,包括天然裂缝密度、裂缝展布形态和不同井区裂缝组合的差异性。同时,根据长63储层岩心裂缝充填情况与充填概率、裂缝结构面力学性质以及裂缝产状与现今水平主应力走向之间的关系,对储层裂缝系统的有效性进行了初步分析。结果表明,储层中无效裂缝居多,达85.6%,有效裂缝仅为14.4%;但经压裂改造后,NEE—NWW向范围内的天然裂缝系统往往易改造或转变为"有效""显"裂缝系统,提高了储层渗流能力。更多还原

【Abstract】 The Chang 63 low reservoir in Yanchang Formation in upper Triassic system in Huaqing area,Ordos basin is the extra low permeable oil layer,and the natural fracture distribution and validity restrict petroleum exploration and development.Based on the statistics method and associating with the rock failure criteria and the strain energy method,the fracture development degree and distribution were quantitatively predicted in the Chang 63 reservoir in Huaqing area by the finite element simulation of the aeolotropism reservoir.According to the quantitative observations of the fractures in orientated drilling cores and thin-slices,The fracture distribution network conceptual model of Chang 63 reservoir was preliminarily erected based on the characteristic parameters of fracture direction,interval,and density,which expressed the essential states of the fractures in the reservoir,including the natural fracture density,distribution pattern and the difference of the fracture composition.And according to the fill degree,fill probability and mechanical property of the constructional surfaces of the fractures in the reservoir and the included angle between the fracture strike and the direction of the maximum horizontal principal pressure,the validity of the fracture systems in the reservoir were preliminarily analyzed.It was held that the invalid fractures were dominant in the reservoir,which had reached 85.6%,while the valid ones only 14.4%.And after hydraulic treatment,the NEE-NWW natural fracture systems were easy to be reconstructed or change to valid ones,which could improve the vadose capacity of reservoir.These results could offer important geological reference for the further oil exploration and the reasonable development decision in the Chang 63 reservoir in Huaqing area.更多还原