摘要
以准噶尔盆地玛湖凹陷风城组致密储层为研究对象,利用真实破裂过程数值模拟平台RFPA软件,研究压裂过程中致密储层井周裂缝的扩展和延伸规律。在此基础上,研究了岩石力学特性以及水平主应力差对地层井周裂缝延伸规律的影响,并利用灰色关联法定量分析各因素对压裂效果的影响程度,以及结合层次分析法构建储层的可压裂性评价模型。结果表明:水平主应力差越大,压裂缝延伸的方向性越明显,地层起裂压力越低,裂缝延伸距离越大;随着抗压强度、抗张强度和弹性模量的增大,地层起裂压力越高,裂缝延伸距离越小,而随着泊松比的增大,地层起裂压力越低,裂缝延伸距离越大;基于灰色关联法,明确了影响压裂效果的因素由高到低排序依次为水平应力差>弹性模量>抗张强度>单轴抗压强度>泊松比;利用层次分析法构建了综合考虑水平应力差、弹性模量、抗张强度及单轴抗压强度等因素影响的储层可压裂性指数计算模型,其与无因次压裂缝缝长、面积均呈较好的正相关性;结合已压裂井试油资料,储层可压裂性指数也与采油强度呈良好的正相关性。
Taking the tight reservoir of Fengcheng Formation in Mahu Depression as the research object,the RFPA software of the numerical simulation platform for the real fracture process was used to study the propaga⁃tion and extension law of reservoir fractures around the well during the fracturing process.On this basis,the in⁃fluence of rock mechanical properties and horizontal principal stress difference on the fracture extension law of the reservoir around the well is studied.Grey correlation method is used to quantitatively analyze the influence degree of each factor on fracturing effect,and combined with analytic hierarchy process,the evaluation model of reservoir fracturing ability is constructed.The results show that the larger the horizontal principal stress differ⁃ence is,the more obvious the directionality of fracture extension is.The lower the fracture initiation pressure is,the larger the fracture extension distance is.With the increase of compressive strength,tensile strength and elas⁃tic modulus,the cumulative number of acoustic emission decreases,and the fracture extension distance decreas⁃es.However,with the increase of Poisson's ratio,the cumulative number of acoustic emission increases,and the fracture extension distance increases.Based on the grey correlation method,the order of influencing the frac⁃turing effect was determined as the horizontal stress difference>elastic modulus>tensile strength>uniaxial compressive strength>Poisson's ratio.Using the analytic hierarchy process(AHP),a model for calculating the reservoir fracturing index is established,which takes into account the influence of horizontal stress differ⁃ence,elastic modulus,tensile strength and uniaxial compressive strength,etc.,and has a good positive correla⁃tion with the extension distance and area of non-dimensional fracture.Combined with the test data of the frac⁃tured well,there is a positive correlation between the fracturability index and the oil recovery intensity.
作者
熊健
刘峻杰
吴俊
刘向君
王振林
梁利喜
张磊
XIONG Jian;LIU Junjie;WU Jun;LIU Xiangjun;WANG Zhenlin;LIANG Lixi;ZHANG Lei(State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation,Southwest Petroleum University,Chengdu 610500,China;Research Institute of Exploration and Development,Xinjiang Oilfield Company,PetroChina,Karamay 834000,China)
出处
《天然气地球科学》
CAS
CSCD
北大核心
2021年第10期1581-1591,共11页
Natural Gas Geoscience
基金
国家科技重大专项(编号:2017ZX05001004-005,2017ZX05070001)
西南石油大学青年科技创新团队项目(编号:2018CXTD13)联合资助.
关键词
数值模拟
压裂缝
扩展规律
水平应力差
可压裂性指数
Numerical simulation
Fracture
Propagation law
Horizontal stress difference
Fracturing index
