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富含粘土的页岩、泥质粉砂岩和粉砂岩等泥质岩的储层矿物成分、微组构和微孔结构复杂,使得泥质岩储层的应力敏感性存在较大差别。以鄂尔多斯盆地延长组泥质岩为研究对象,开展应力敏感性实验评价研究,并与典型致密砂岩储层进行对比。结果表明,页岩的应力敏感程度强,泥质粉砂岩中等—偏强,致密砂岩弱;在30MPa有效应力作用下,岩石呈现塑性变形。分析指出,岩石的变形主要受到岩石的组分、胶结物类型和含量、微裂缝系统、孔隙结构参数、骨架颗粒形态、接触方式、粒度分布、粘土微结构等参数的影响。针对3类岩石的应力敏感性差异,应区别对待,尽力控制储层应力敏感性损害的发生。
The clay minerals such as shale, muddy siltstone and siltstone in clay-rich shale have complex micro-structure and microporous structure, which make the stress sensitivity of shale reservoirs to be quite different. Taking the Yanchang Formation argillaceous in the Ordos Basin as the research object, the stress sensitivity experiment evaluation is carried out and compared with the typical tight sandstone reservoir. The results show that the shale is strong in stress sensitivity, medium-strong in muddy siltstone and weak in tight sandstone. Under the effective stress of 30MPa, the rock exhibits plastic deformation. The analysis shows that the deformation of rock is mainly affected by the composition of rock, type and content of cements, microcrack system, pore structure parameters, morphology of framework particles, contact mode, particle size distribution and clay microstructure. For the three types of rock stress sensitivity differences, should be treated differently, try to control the occurrence of reservoir stress sensitivity damage.