水平井压裂储层应力场扰动规律研究

发布时间：2018-04-09 03:23

本文选题：水平井压裂　切入点：应力场　出处：《东北石油大学》2016年硕士论文

【摘要】：水平井压裂是改造开发非常规储层的主要手段之一,与常规压裂不同的是水平井压裂以形成复杂裂缝网络为目标。而应力场是影响裂缝起裂和扩展的关键,本文以水平井压裂过程中的裂缝周围应力场为对象进行了深入的研究。首先,基于前人的水平井井周应力模型和裂缝诱导应力模型,建立了考虑多因素影响的水平井压裂扰动应力场计算数学模型,确定了压裂过程中应力场的影响因素;之后引入应力-渗流-温度多场耦合理论,建立了水平井压裂扰动应力场的有限元分析模型,并对其进行了验证,提出了有限元求解方法。根据水平井压裂扰动应力场的计算模型,采用有限元数值软件COMSOL Multiphysics模拟计算了不同地层参数、水平井筒方位角、裂缝参数以及压裂布井方式影响下的单井单缝、单井多缝以及多井多缝之间的应力场分布情况,其中地应力参数包括水平主应力比值及地层泊松比,裂缝参数包括裂缝净压力、裂缝长度、裂缝间距、裂缝条数以及裂缝分支数的简繁,压裂布井方式则包括两口井并排同步压裂、错位交替压裂、拉链式压裂以及改进的拉链式压裂,通过分析不同方案下的应力场扰动情况,确定了各主控因素对压裂应力场的扰动规律。最后考虑天然裂缝的影响,利用Baecher椭圆盘模型表征随机天然裂缝的形状,再引入Markov Chain Monte Carlo(MCMC)方法随机抽样,重构出储层天然裂缝;通过分析随机天然裂缝对应力场的扰动规律,以压裂裂缝垂直最小水平主应力方向起裂为前提,确定了天然裂缝与人工裂缝协同扰动作用下的人工裂缝扩展路径。研究有利于更加清楚地认识了解水平井压裂储层应力场分布规律,为有效控制改造储层应力场形成复杂缝网提供了理论依据,对实现非常规储层开发具有重要意义。
[Abstract]:Horizontal well fracturing is one of the main methods to reconstruct and develop unconventional reservoir. Different from conventional fracturing, horizontal well fracturing aims at forming complex fracture network.The stress field is the key to the fracture initiation and propagation. The stress field around the fracture in horizontal well fracturing is studied in this paper.Firstly, based on the stress model of horizontal well and fracture induced stress model, the mathematical model of disturbance stress field of horizontal well fracturing is established, and the influencing factors of stress field in fracturing process are determined.Then the finite element analysis model of fracturing disturbance stress field in horizontal wells is established by introducing the stress-percolation-temperature coupling theory and the finite element method is put forward.According to the calculation model of fracturing disturbance stress field in horizontal wells, the single well fracture affected by different formation parameters, horizontal wellbore azimuth angle, fracture parameters and fracturing pattern is simulated by finite element software COMSOL Multiphysics.The distribution of stress field between single well and multiple fractures, in which the in-situ stress parameters include horizontal principal stress ratio and formation Poisson's ratio, fracture parameters include net fracture pressure, fracture length, fracture spacing,The fracturing pattern consists of two wells simultaneously fracturing, staggered fracturing, zipper fracturing and improved zipper fracturing. By analyzing the disturbance of stress field under different schemes, the fracturing pattern is simple and complex.The disturbance law of main controlling factors to fracturing stress field is determined.Finally, considering the influence of natural fractures, using Baecher elliptic disk model to characterize the shape of random natural fractures, and then introducing the Markov Chain Monte Carlos MCMC method to random sampling to reconstruct the natural fractures in reservoir, the disturbance law of random natural fractures corresponding to force field is analyzed.On the premise of fracture initiation in the direction of vertical minimum horizontal principal stress of fracturing fracture, the propagation path of artificial fracture under the synergistic disturbance of natural fracture and artificial fracture is determined.The study is conducive to a clearer understanding of the distribution of stress fields in fracturing reservoirs in horizontal wells, and provides a theoretical basis for effectively controlling the formation of complex fracture networks in reservoir stress fields, which is of great significance to the development of unconventional reservoirs.
【学位授予单位】：东北石油大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TE357

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