利用地应力评价地下储气库断层密封性方法及应用  

Method and application of in-situ stress field to evaluate fault sealing of underground gas storage traps

作　　者：张广权[1] 曾大乾[1] 范照伟 糜利栋 张俊法[1] 王丹丹[1] 贾跃玮[1] 杨小松[1] ZHANG Guang-quan;ZENG Da-qian;FAN Zhao-wei;MI Li-dong;ZHANG Jun-fa;WANG Dan-dan;JIA Yue-wei;YANG Xiao-song(SINOPEC Petroleum Exploration and Production Research Institute,Beijing 100083,China)

机构地区：[1]中国石化勘探开发研究院,北京100083

出　　处：《天然气地球科学》2021年第6期923-930,共8页Natural Gas Geoscience

基　　金：中国石化科技部项目群“中国石化地下储气库建设关键技术研究”(编号:P18096);国家自然科学基金(编号:51804334)联合资助。

摘　　要：目前对不同地区不同类型地下储气库圈闭密封性的评价方法差异较大,尤其在圈闭断层动态密封性方面,没有一套系统的、完整的评价方法和体系。在调研大量国内外储气库密封性评价文献的基础上,结合国内27座已建储气库的密封性评价实例,提出了一种利用应力场评价储气库圈闭断层动态密封性的方法。从地质力学角度考虑,通过分析注采过程中应力场的变化,评价储气库圈闭的动态密封性。首先,进行单井地应力参数计算,建立现今三维地应力场,分析各主应力与有效应力的空间分布。其次,利用Coulomb破坏准则,判断现今地应力状态下断层稳定性。最后,在三维地应力模型和三维数值模型的基础上,进行多周期注采、交变载荷下储气库断层动态密封性评价,结合储气库的历史拟合和数值模拟成果,主要是模拟多个注采周期内孔隙压力的变化,建立应力—流体的动态耦合模型,分析储气库注采过程中随着孔隙压力变化引起地应力的动态变化(有效应力)过程,进而评价断层密封性的应力风险。运用该方法,可以明确储气库在不同注采周期下储气库能否安全运行。At present,there are great differences in the evaluation methods of underground gas storage traps in different regions and types,especially in the aspect of fault dynamic sealing,there is no systematic and complete evaluation method and system.Based on the investigation of a large number of literatures on sealing evaluation of gas storage at home and abroad,combined with the sealing evaluation examples of 27 built gas storages in China,this paper puts forward a method to evaluate the dynamic sealing property of gas storage traps by using stress field.From the perspective of geomechanics,the dynamic sealing property of gas storage traps is evaluated by analyzing the change of stress field in the process of injection and production.Firstly,the in-situ stress parameters of single well are calculated,the current three-dimensional in-situ stress field is established,and the spatial distribution of principal stress and effective stress is analyzed.Secondly,the Coulomb failure criterion is used to judge the fault stability under the present in-situ stress state.Finally,the main purpose of this paper is to establish a three-dimensional numerical model to simulate the dynamic change of reservoir pressure and the cyclic pressure of gas injection reservoir.The process of dynamic change(effective stress)of in-situ stress caused by the change can be used to evaluate the stress risk of fault sealing.This method can be used to determine whether the gas storage can be operated safely under different injection production periods.

关 键 词：地下储气库 密封性评价 地应力 孔隙压力 耦合模型 

分 类 号：TE121[石油与天然气工程—油气勘探]