高压注水引起套损的机理研究

高压注水开采，在多孔介质中形成渗流场，使钻井后储层的固体骨架应力重新分布，通过有效应力改变储层岩体的渗流参数，影响渗流场与岩体应力场两者的平衡。高围压下的井眼附近容易产生应力集中和塑性屈服，储层经过上述流固耦合作用后，由于储层多为砂岩、泥岩等不同岩性、不同厚度岩层相互分层夹杂，各层间力学参数对注水干扰和应力重新分布的敏感性都有较大差异，井眼作为唯一较大的储层应力和位移释放的空间，周围储层产生的应力重新分布结果会直接对套管、固井水泥环和周围储层岩体这一组合体系产生弹塑性应力作用，产生新的应力集中，并伴随各部位应变的差异，从而导致套管破坏。

Study on the Mechanism of Oil Well Casing Collapse Caused by Injecting Water with High Pressure

The porous flow and the stress distributing of the rock body in oil reservoir is changed after the high pressure of injecting water,the parameters are changed at the same time with the changing of the effective stress which can affect the balance of the porous field and stress field.The plastic yield and stress concentrating often come into being near the well-bore under high wall-rock pressure.To the point of the injection and the stress re-distribution after the fluid-solid coupling interaction,the mechanical parameters in the Layers are quite different from the much amount of sandstone and mudstone in oil reservoir with different thickness and quality.The well hole is the only big room in the reservoir for the stress and displacement release where the stress distribution will make the casing pipe-cement sheath-rock mass system in the well engender new stress distribution and strain difference,then causing the casing damage.