工程扰动下煤层气储层井周煤岩力学行为与稳定性研究

项目名称： 工程扰动下煤层气储层井周煤岩力学行为与稳定性研究

项目编号： No.51474185

项目类型： 面上项目

立项/批准年度： 2015

项目学科： 矿业工程

项目作者： 范翔宇

作者单位： 西南石油大学

项目金额： 86万元

中文摘要： 受钻进、储层压裂改造等工程扰动影响，煤层气储层井周煤岩破碎，结构强度显著降低，加之所处地质环境复杂，井工灾害尤其是失稳破坏时常发生，严重制约煤层气开发。本项目拟通过热流固耦合力学实验，研究含煤层气煤岩力学、强度特性；通过工程扰动下井周煤岩力学行为模型实验，研究煤层气储层井周煤岩失稳破坏机制与模式。基于岩石力学、断裂力学、损伤力学理论，建立含煤层气煤岩在温度、应力及渗流场下的热流固耦合本构模型；结合突变理论、分形理论、模糊数学及神经网络等非线性科学方法，定量推算井周煤岩失稳破坏的力学条件。并采用COMSOL数值软件，分析工程扰动下煤层气储层井周煤岩力学行为及稳定性。最终提出在工程扰动下井周煤岩破坏失稳机理与判据。研究成果不仅能促进煤层气储层井周煤岩失稳灾害非线性动力学理论体系的产生与发展、加快煤层气勘探开发进程，且可为有效解决常规天然气开采中穿越煤层的井壁稳定问题及深部煤炭开采提供理论指导。

中文关键词： 钻井工程；岩石力学；流固耦合；井壁稳定；数值模拟

英文摘要： Under the effect of drilling and reservoir fracturing, the surrounding coal of coalbed methane reservoir wellbore is cracked with low mechanical strength and complex geological environment, coalbed methane wellbore disasters expecially the instability of surrounding coal of wellbore occur frequentley, which seriously restrict the exploration of coalbed methane. In this project, the mechanicle characteristics of thermo-fluid-solid coupling of coal containing methane will be studied through the mechanical experiments of thermo-fluid-solid coupling. The deformation and failure rules of surrounding coal of coalbed methane reservoir wellbore will be investigated through model tests. According to the experimental results, based on the theories of rock mechanics, fracture mechanics and damage mechanics, a constitutive model for thermo-fluid-solid coupling of coal containing methane on the condition of temperature, stress and seepage gradient will be built. Furthermore, combining with the theory of non-linear science, such as mutation theory, fractal theory, fuzzy mathematic theory and artificial neural network, the instability mechanical condition of surrounding coal of coalbed methane reservoir wellbore will be obtained quantificationally. Moreover, the mechanical behavior and stability of surrounding coal of coalbed methane reservoir wellbore under the effect of drilling and reservoir fracturing will be analyzed with the numerical analysis software of COMSOL. Finally, the instability mechanism and failure criterion of surrounding coal of coalbed methane reservoir wellbore under the effect of drilling and reservoir fracturing will be put forward. The results will not only stimulate the emergence and development of the theoretical system of non-linear dynamics of instability disaster of surrounding coal of coalbed methane reservoir wellbore and accelerate the process of exploitation and development of coalbed methane, but also provide theoretical guidance for solving the wellbore stability problem in drilling conventional natural gas acrossed coal seam and coal mining in deep strata.

英文关键词： drilling engineering;rock mechanics;fluid-solid coupling;wellbore stability;numerical simulation