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地应力是影响储层物性参数的重要因素,特别是对地应力敏感的储层。实验研究表明,不管是干燥岩石还是含束缚水岩石,低渗透砂岩气藏储层的应力敏感性是客观存在的,而且这种应力敏感性对储层渗透率造成的伤害不可忽视。随着有效压力的升高,渗透率是逐渐降低的。低渗透气藏岩心的孔隙度随有效压力的增大呈指数关系递减。低渗透气藏应力敏感性与储层含水饱和度有关,束缚水饱和度越高,应力敏感性越强。低渗透气藏孔隙变形具有弹塑性变形的特征。
In-situ stress is an important factor that affects reservoir physical properties, especially for geostrophic reservoirs. Experimental results show that the stress sensitivity of low-permeability sandstone reservoirs is objective, whether it is dry rock or irreducible water, and the damage caused by this stress sensitivity to reservoir permeability can not be neglected. As the effective pressure increases, the permeability decreases gradually. The porosity of cores in low permeability reservoirs decreases exponentially with the increase of effective pressure. The stress sensitivity of low permeability gas reservoirs is related to the water saturation of reservoirs. The higher the irreducible water saturation, the stronger the stress sensitivity. The pore deformation of low permeability gas reservoirs has the characteristics of elastoplastic deformation.