摘要
页岩油储层物性极差,必须通过体积压裂改造形成网状裂缝系统才能实现经济有效开发。而页岩油储层上下均有渗透性更差的隔层,掌握有隔层情况下的储层裂缝扩展规律是页岩油成功压裂的关键。借助岩石破裂损伤分析系统数值模拟软件RFPA,开展了储隔层压裂缝扩展影响因素研究。在考虑了地层非均质的前提下,综合考虑储隔层弹性模量、储隔层泊松比、储隔层单轴抗压强度、储隔层抗拉强度、水平应力差异以及层间应力差这几种影响因素,采用层次分析法进行了页岩油储层可压性评价。结果表明,储隔层的弹性模量和水平地应力差以及储层的单轴抗压强度都与裂缝扩展程度呈负相关性,随着这些参数的增加,裂缝越难扩展。而储层的压拉比和储隔层层间应力差与裂缝扩展程度呈正相关性,即抗拉强度和层间应力差的增大将会有利于加大裂缝扩展的规模,并且较大的层间应力差还会使裂缝穿过隔层,在隔层继续发展;采用模糊数学中的层次分析法建立可压性数学模型,应用于工区已压裂井,预测结果与实验微地震监测结果相符,研究成果可为页岩油压裂改造提供参考。
The physical properties of shale oil reservoir are extremely poor,so it is necessary to form a network fracture system through volume fracturing to realize economic and effective development.However,there are lower permeability interlayers both in the top and bottom of shale oil reservoirs,so to master the fracture propagation law of reservoir with interlayers is the key for the successful fracturing of shale oil.With the help of the numerical simulation software,RFPA,of the rock fracture damage analysis system,the influencing factors of fracture propagation in the reservoir interlayers are studied.On the premise of considering the heterogeneity of strata,and by the comprehensively consideration of the elastic modulus,Poisson’s ratio,uniaxial compressive strength,tensile strength,horizontal stress difference and interlayer stress difference of the reservoir,the fracability of shale oil reservoir is evaluated by the analytic hierarchy process.The results show that the elastic modulus of the reservoir interlayer,the difference of horizontal in-situ stress and the uniaxial compressive strength of the reservoir are negatively correlated with the degree of crack propagation.As these parameters increase,the cracks are more difficult to expand.However,there is a positive correlation between the ratio of tension and compression of reservoir and the stress difference between layers of reservoir and the degree of fracture propagation,that is,the increase of tensile strength and interlayer stress difference will help to increase the scale of fracture propagation,and the larger interlayer stress difference will make the fractures pass through the interlayers and continue to develop in the interlayer.Meanwhile,the mathematical model of the fracability is established by the analytic hierarchy process in fuzzy mathematics,and applied to the fractured wells in the work area.The predicted results are consistent with the experimental microseismic monitoring results,and the research results can provide reference for shale oil fracturing reform.
作者
刘叶轩
刘向君
丁乙
周鑫
梁利喜
LIU Yexuan;LIU Xiangjun;DING Yi;ZHOU Xin;LIANG Lixi(State Key Laboratory of Oil and Gas Reservoir Geology and Development Engineering,Southwest Petroleum University,Chengdu,Sichuan 610500,China)
出处
《油气藏评价与开发》
CSCD
2023年第1期74-82,共9页
Petroleum Reservoir Evaluation and Development
基金
国家自然科学基金项目“富有机质硬脆性页岩水化机理基础研究”(41772151)。
关键词
页岩油藏
隔层
可压性
数值模拟
层次分析法
shale reservoir
interlayer
fracability
numerical simulation
analytic hierarchy process
