【作者】 马洪岭；

【导师】 杨春和；

【作者基本信息】 中国科学院研究生院（武汉岩土力学研究所） ， 岩土工程， 2010， 博士

【摘要】 盐岩是世界上公认的油气储备的理想介质,国内已经对盐岩地下储气库展开了研究,金坛已有溶腔地下储气库于2007年底开始注气,云应盐岩地下储气库也已经通过了可行性论证。国外盐岩地下储库的埋深一般为1000-1800米之间,国内预对1800米下的潜江超深地层盐岩油气储库进行可行性研究,超深地层有高温高压的特点,带来了一系列的问题与挑战。本文以潜江超深地层油气储库为依托,针对超深地层高温高压的特性,系统展开了高温高压条件下的力学试验研究,根据盐岩的破坏特点建立了盐岩的强度理论,结合数值模拟的手段对超深地层盐岩地下储气库的稳定性进行了研究,主要研究内容及结论如下：1.模拟2000米处地层温度和压力,进行了不同温度和不同压力条件下的压缩试验。研究了高温高压条件下盐岩的力学特性,获取了力学参数。对比了高温高压条件下与常温压条件下的力学特性的区别,研究了围压及温度对盐岩力学特性的影响。2.针对储气库不断进行注气、采气的特点,进行了单轴、三轴加卸载试验,研究了屈服面下的加卸载变形特性,建立了屈服面下的加卸载本构关系。3.进行了高压条件下的盐岩蠕变试验。研究了长时间下蠕变曲线的特征,根据试验结果,获取了稳态蠕变率参数。提出了考虑偏应力效应的初始蠕变本构关系,建立全过程蠕变本构方程,提出了判定盐岩蠕变破坏的加速蠕变边界线。4.提出了考虑高温高压力学特性的盐岩复合强度理论,基于试验,建立了剪切破坏准则、拉伸破坏准则,以及高于临界围压的不坏准则,建立了表征盐岩渗透特征的扩容准则。根据强度理论,对盐岩地下溶腔的围岩体分为弹性区、塑性区、扩容区以及破坏区,基于围岩体分区,建立了盐岩地下储气库围岩体稳定性判断准则。5.基于前面建立的理论模型,在FLAC3D平台上,利用VC++自定义本构,利用模型验证了自编本构的正确性。基于自定义本构以及通过试验获取的力学参数,进行了超深地层盐岩地下储气库的数值模拟分析,综合考虑静力稳定性计算结果与长期蠕变分析结果,建议储气库长期最小运行压力为17MPa,紧急供气时内压可以最低降到10MPa,10MPa-17MPa的库容量可以作为短期应急供气库容量；套管鞋和腔顶的最小距离不少于8米。两倍溶腔直径的矿柱宽度是安全可行的。更多还原

【Abstract】 Rock salt is a worldwide-recognized ideal medium for storing oil and natural gas. Rock salt underground gas storage has been studied for several years in our country. Discarded salt cavities in Jintan have been used to store natural gas for the first time in the world in 2007, and the feasibility of rock salt storage in Yunying has been demonstrated in 2009. From 1000 to 1500 meters, it is the most economical formation for rock salt underground gas storage. But there are some principles for selecting the suitable formation, so the selected formation may be not the most economical one. For the formation of over 1800m, which is called ultra-deep formation, its temperature and pressure are much higher than the common formation. According to the feather of the ultra-deep formation, systematic mechanical tests in high temperature and high pressure have been conducted for Qianjiang rock salt underground gas storage, which is in formation of 1990m to 2080m. Based on the fracture feather, strength theory of rock salt has been built. The stability of ultra-deep salt rock underground gas storage has been researched by numerical simulation method. The main contents and conclusions are as follows:1. Based on the temperature and pressure in 2000-meter formation, compression tests in different temperatures and pressures were conducted. The mechanical properties in high temperature and pressure were studied, and mechanical parameters were obtained. The differences of mechanical properties under high and normal temperatures and pressures were compared. The effects of confining pressure and temperature on rock salt mechanical property were researched.2. According to the characteristics of cyclic gas injection and production, uniaxial and axial cyclic loading and unloading test were conducted. The deformation properties of loading and unloading under yield surface were studied, and the constitutive relationship between loading and unloading was given.3. Creep tests in high pressure were conducted, and the feather of long-time creep curve was researched. Based on the test result, the steady-state creep rates were obtained. The primary creep constitutive relationship, which considering the effect of deviatoric stress, was built. Then global creep constitutive equation was given. The accelerated creep boundary line was presented to determine creep failure.4. Strength theory which is considering the effect of high temperature and pressure was built. Based on the tests, shear failure criterion, tension failure criterion and the stability criterion over critical confining press were built. The dilation criterion which represents permeability properties was built based on compress tests. The surrounding rock mass of rock salt dissolved cavity can be divided into elasticity zone, plasticity zone, dilation zone and failure zone; based on the zones, stability criterion was built.5. Based on the theory model built previous, self-defined constitutive was compiled to the interface of FLAC3D by VC++6.0, and validity of self-defined constitutive was verified by using a tunnel model. Based on the self-defined constitutive and parameters obtained by tests, numerical simulation analysis was conducted for the rock salt underground gas storage in ultra-deep formation. Considering results of stability and creep analysis, 17MPa was advised to be the long-term minimum pressure. When gas supply is emergency, the pressure can be dropped to 10MPa, and the storage capacity between 10MPa to 17MPa can be used as short-term emergency gas supply. The minimum distance between casing shoe and cavity roof is 8 meters, and two times of cavity diameter is feasible for the pillar width.更多还原