超深盐穴储气库的建设是多年来存在的一大难题。本文选取宁晋盐穴储气库,通过单轴压缩试验、三轴压缩试验研究超深盐岩的力学特性,利用FLAC3D软件建立盐腔的稳定性分析模型,以期为宁晋盐穴储气库的钻完井工艺、建腔工艺、注采工艺提供参考。结果表明:(1)在单轴压缩试验过程中,盐岩表现一定的脆性,泥岩、细砂岩表现出明显的脆性;在相同应力状态下,盐岩的变形能力好于泥岩、细砂岩,盐岩的弹性模量平均值为4.79 GPa,泊松比平均值为0.07,抗压强度平均值为22.01 MPa;(2)在三轴压缩试验过程中,围压大于5 MPa时,盐岩表现出比泥岩、细砂岩更明显的延性岩石的特点;盐岩破坏形式以鼓胀为主,应变硬化现象随着围压增强,没有明显破裂面,有很强的塑性变形的特点;(3)通过稳定性分析,随着内压增大,腔周的扩容区逐渐减小,腔壁的位移逐渐较小,宁晋盐穴储气库的运行内压不低于20 MPa。

Construction of ultra-deep salt cavern gas storage is a difficult problem for many years. For the benefit of this problem, selecting Ningjin Salt Cave Gas Storage, the mechanical properties were studied by uniaxial compression tests and triaxial compression tests, and the stability analysis model of salt chamber was established by FLAC3D so as to provide reference for drilling and completion technology, cavity construction technology, injection and production technology of salt cavern gas storage in Ningjin. by researching: (1) According uniaxial compression tests, salt rock possesses certain brittleness, mudstone and fine sandstone show obvious brittleness. The deformation capacity of salt rock is better than that of mudstone and fine sandstone under the same stress state. The average of elastic modulus of salt rock is 4.79 GPa, the average of poisson's ratio is 0.07, The average of compressive strength is 22.01 MPa. (2) According to the test of triaxial compression, salt rock show more obvious characteristics of ductile rock than mudstone and fine sandstone when the confining pressure is greater than 5MPa. The main form of destruction is bulging, the behavior of strain-hardening increase with the confining pressure, no obvious fracture surface, salt rock has strong plastic deformation characteristics. (3) The expansion area and displacement of cavity wall decrease gradually with the increase of internal pressure,internal pressure of Ningjin salt cavern gas storage is not less than 20 MPa.