煤岩层水力裂缝扩展形态研究

发布时间：2018-02-14 07:22

本文关键词： 煤岩层割理系统等效岩石力学参数裂缝扩展裂缝形态　出处：《西南石油大学》2015年硕士论文　论文类型：学位论文

【摘要】：煤岩层非均质性较强、割理系统发育、地质特征独特,是典型的低孔、低渗、裂缝性储层。煤岩层气井压裂施工中出现砂比低、施工压力波动剧烈、易出现砂堵等现象,这与煤岩层水力裂缝扩展形态紧密相关。考虑到煤岩层独特的地质与工程特征,其水力裂缝扩展规律不能参照常规及其他非常规油气藏,目前国内外关于煤岩层水力压裂裂缝扩展规律的研究还不够完善,有必要进一步开展此类研究。本论文基于流体力学、断裂力学力学和渗流力学的相关理论认识,结合煤岩层孔渗特征、滤失特征、割理系统等因素,分析研究煤岩层压裂裂缝扩展形态变化规律,研究主要分为三部分：论文建立了等效岩石力学参数模型,表征煤岩层非连续性；采用复变函数法求取煤岩层复合裂纹应力强度因子,并建立了复合裂纹扩展判据与水力裂缝天然裂缝相交判定准则；考虑割理系统与应力敏感性对煤岩层滤失的影响,建立了煤岩层滤失模型,在此基础上建立了煤岩层水力裂缝扩展模型进而对水力裂缝在煤岩层中的扩展机理进行了深入的研究,分析了施工参数、天然裂缝参数、岩石力学参数及割理特性对煤岩层裂缝扩展形态的影响规律。根据上述理论研究可知,煤岩层与常规及其他非常规油气藏在压裂液滤失与裂缝扩展形态等方面具有较为明显的差异,本论文研究为煤岩层水力裂缝扩展规律及水力裂缝形态的精细化研究提供了一定的理论指导。
[Abstract]:The coal and rock strata are characterized by strong heterogeneity, developed cleat system and unique geological characteristics. They are typical low porosity, low permeability and fractured reservoirs. The phenomena of low sand ratio, severe fluctuation of operation pressure and easy sand plugging are found in the fracturing of coal and rock formation gas wells. This is closely related to the formation of hydraulic fractures in coal and rock formations. Considering the unique geological and engineering characteristics of coal and rock formations, the rules of hydraulic fracture propagation cannot be referred to conventional or other unconventional reservoirs. At present, the research on fracture propagation law of coal formation hydraulic fracturing is not perfect at home and abroad, so it is necessary to further develop this kind of research. Based on the related theories of fluid mechanics, fracture mechanics and percolation mechanics, this paper analyzes and studies the variation law of fracture propagation and morphology of coal bed fracturing by combining the characteristics of pore and permeability of coal and rock formation, filtration characteristics, cleat system and so on. The research is mainly divided into three parts: the equivalent rock mechanics parameter model is established to characterize the discontinuity of coal strata, the complex variable function method is used to calculate the stress intensity factor of coal rock stratum composite crack, The intersecting criterion of complex crack propagation criterion and hydraulic fracture natural fracture is established, considering the influence of cleat system and stress sensitivity on coal bed filtration, a coal bed filtration model is established. On the basis of this, the hydraulic crack propagation model of coal and rock bed is established, and the mechanism of hydraulic crack propagation in coal bed is studied deeply. The construction parameters and natural fracture parameters are analyzed. The influence of rock mechanical parameters and cleat characteristics on fracture propagation morphology of coal strata. According to the above theoretical study, there are obvious differences in fracturing fluid filtration and fracture propagation morphology between coal and rock formations and conventional and other unconventional reservoirs. This paper provides some theoretical guidance for the detailed study of hydraulic fracture propagation law and hydraulic fracture morphology of coal bed.
【学位授予单位】：西南石油大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TE357.1

【参考文献】