【作者】 赵克烈；

【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， 2009， 博士

【摘要】 盐岩的低渗透性能保证储库的密闭性;良好的蠕变行为和损伤自我恢复性可保证其力学稳定性,以适应储库压力的变化。因此,盐岩已被公认为储存天然气的理想场所。鉴于我国能源的需求、储备的实际情况和盐矿资源分布情况,储库的建设得到了国家和许多学者越来越多的重视。本文以我国第一个地下盐岩储气库(江苏金坛储气库)为示范工程,系统开展了地下盐岩储气库运营中两个阶段(注气排卤阶段和注采周期阶段)相关力学问题的研究。主要研究内容及研究成果如下:1、通过单三轴压缩、直剪、单三轴蠕变实验研究了盐岩的力学特性,得到了蠕变损伤模型在数值计算中所需要的参数。2、针对地下储气库中数值计算结果难以验证的问题,利用废弃溶腔建立了观察井来监测溶腔由于蠕变引起的体积收缩,并通过实验和理论推导,验证了该方法在理论和实践上的合理性。利用监测数据,通过优化反演的方法得到了金坛盐岩蠕变损伤本构模型的实际蠕变参数,并应用于以后各章的数值计算中。3、针对储气库在注采过程中受周期荷载,将其考虑为蠕变损伤和疲劳损伤的交互作用,用理论推导的方法得到了一个新的蠕变.疲劳交互损伤模型。利用力学实验的方法,研究了盐岩在单、三轴周期荷载作用下的疲劳特性,并利用试验数据回归了蠕变-疲劳交互损伤模型的参数。利用数值软件中对材料本构模型进行二次开发留下的接口,通过VC++对盐岩蠕变-疲劳交互损伤本构模型进行了编程。4、针对注气排卤系统中腔内压力变化规律,主要研究了注气排卤中气液界面的确定方法;分析和推导了注气压力、气液面高度、排卤速度等因素的关系式,并利用注气压力理论计算值和实际监测数据相比较,验证了该关系式在实际工程中的可用性.。最后建立了金坛6口溶腔的三维数值模型,运用蠕变损伤本构模型和Cosserat扩展介质本构模型对腔体在注气排卤期间的可用性及细小夹层对可用性的影响进行了研究。5、运用蠕变损伤模型和蠕变-损伤交互损伤本构模型考虑了注采运行中恒定内压、采气速率、循环次数三个因素对储气库体积变形规律的影响,获得了一些有益结论,并应用于指导注采气运行方案的制定。更多还原

【Abstract】 Salt rock with low permeability can ensure the tightness of the storage in salt rock formation and its good creep behavior and ability of self-recovery of damage can lead to stable mechanical behaviors so that it can adapt well to the variation of the pressure of the storage. As a result, salt rock is a well-known ideal medium for the storage of natural gas. In light of our energy demand, the present status of energy storage and the distribution of salt mines, the whole country and many researchers have attached increasing importance to the construction of gas storages. Taking the first underground salt rock gas storage in our country (Jiangsu Jintan gas storage) as an example, the paper gives a systematic analysis of the mechanical problems involved in the two phases of the operation of the underground salt rock gas storage (the phase of gas injection and brine discharge and the periodic phase of gas injection and production). The main research results are as follows:1. With the mechanical characteristics of salt rock investigated by uniaxial and triaxial compression test, direct shearing test, and uniaxial and triaxial creep test, the parameters needed in numerical calculations are obtained for the creep damage constitutive model.2. In response to the fact that results of numerical calculation are difficult to testify in underground gas storages, the author works out a method that is proved to be reasonable both theoretically and practically by experiment and theory deduction. It is to build an observation well out of an abandoned cavity to monitor the volume contraction caused by creep. Then the monitored data can be used to obtain by optimization and inversion the actual creep parameters of the creep damage constitutive model which can later be applied into numerical calculations in each chapter.3. Provided that gas storage is subject to periodic load in the process of gas injection and production and taken into account the interaction between creep damage and fatigue damage, a new creep-fatigue damage constitutive model is produced by the means of theory deduction. The fatigue properties of salt rock under the effect of uniaxial and triaxial periodic load are investigated by making mechanical experiments. At the same time, the parameters of the creep-fatigue damage constitutive model are obtained from the experimented data. By making use of the interface left in the second development process of material constitutive model in numerical software, the creep-fatigue damage constitutive model of salt rock is programmed by VC++. 4. Based on the law of cavity pressure change in the gas injection and brine discharge system, how to identify the interface between gas and liquid while conducting gas injection and brine discharge is studied. Meanwhile, formulae concerning elements such as pressure of gas injection, height of gas and liquid level and speed of brine discharge are analyzed and established. In addition, the usability of such formulae in real projects is testified by making comparison between the values calculated through the theory of gas injection pressure and the data monitored on real sites. At last with a three-dimensional numerical model of the six cavities in Jintan successfully built, some researches are carried out to study the practicality of creep damage constitutive model and expanding Cosserat medium constitutive model in cavity during the period of gas injection and brine discharge as well as the influences of the tiny interlayer on the usability.5. The effects of three factors (constant internal pressure, rate of gas production and circling times) on the deformation law of gas storage volumes during the operation of gas production are considered by using creep damage constitutive model and creep-fatigue damage constitutive model, which leads to some helpful conclusions that can be applied to guide the formulation of a scheme for operating gas injection and production.更多还原