水平井压裂裂缝扩展数值模拟研究

发布时间：2018-04-11 10:07

本文选题：水力压裂 + 裂缝　；参考：《西南石油大学》2017年硕士论文

【摘要】：平井分段压裂技术作为油气勘探开发领域核心和热点技术之一,极大的推动着低渗透难动用油气资源的开发进程。压裂裂缝形态是现场压裂工程师普遍关心的问题,其很大程度上决定着压后增产效果,因此压裂裂缝形态的预测具有重要意义。水平井分段压裂过程中,多裂缝产生诱导应力相互作用不断扰动局部地应力场,加之地质和施工参数的影响,多裂缝的延伸受控机理极其复杂。分段压裂裂缝的延伸机理和形态预测还有待进一步深入研究。基于此背景,本文以水平井压裂裂缝扩展数值模拟为主题,开展的工作和得到的认识如下。(1)在调研对比分析了各类现有裂缝扩展模拟数值方法的特点及各自优缺点基础上,选用了优势的扩展有限单元法并总结归纳了其用于模拟水力压裂裂缝扩展时的各类特殊单元的处理方法。(2)基于平面应变假设,结合线弹性力学和断裂力学等理论建立了水力压裂裂缝扩展数学模型,并基于模型和流固耦合方法,编写了水平井分段压裂裂缝扩展模拟计算机程序,实现了水力裂缝扩展模型的求解。(3)在验证本文模型和程序可靠性的基础上,模拟分析了段内多簇缝的同时延伸行为,模拟结果表明:诱导应力作用使得中缝尺寸受到抑制而边缝则相互排斥延伸;液量、岩石杨氏模量和地应力差与裂缝长度呈不同程度上的正相关关系,压裂液黏度与缝长呈反相关关系,地层岩石泊松比对缝长影响不明显。(4)三簇压裂时,地质和工程参数对裂缝的转向角影响规律为:黏度、排量、岩石杨氏模量和泊松比越大,边缝越容易转向;簇间距和应力差越大,边缝转向角越小。本文研究进一步揭示了水平井多簇压裂裂缝延伸规律和控制机理,编制的程序可用于分析各因素对压裂的影响规律。
[Abstract]:As one of the core and hot technologies in the field of oil and gas exploration and development, the horizontal well fracturing technology has greatly promoted the development process of low permeability and difficult to produce oil and gas resources.Fracturing fracture morphology is a common concern of field fracturing engineers, which largely determines the effect of increasing production after pressure, so the prediction of fracturing fracture morphology is of great significance.In the process of horizontal well fracturing, the induced stress interaction of multiple fractures constantly disturbs the local ground stress field, and the influence of geological and construction parameters makes the extension and control mechanism of multiple fractures extremely complex.The extension mechanism and morphology prediction of fracturing fracture need to be further studied.Based on this background, this paper focuses on the numerical simulation of fracture propagation in horizontal wells. The work and understanding obtained are as follows: 1) on the basis of investigation and comparison, the characteristics of various existing numerical methods for fracture propagation simulation and their respective advantages and disadvantages are compared and analyzed.The advantage extended finite element method is selected and the treatment methods of various special units used to simulate hydraulic fracturing fracture propagation are summarized and summarized based on plane strain hypothesis.Based on the theory of linear elasticity and fracture mechanics, the mathematical model of fracture propagation in hydraulic fracturing is established. Based on the model and fluid-solid coupling method, a computer program for simulating fracturing fracture propagation in horizontal wells is developed.On the basis of verifying the reliability of the model and the program, the simultaneous extension behavior of multi-cluster joints in the section is simulated and analyzed.The simulation results show that the induced stress results in the inhibition of the size of the middle seam and the repulsive extension of the edge joint, and the amount of fluid, the Young's modulus of rock and the difference of in-situ stress are positively correlated with the length of the fracture to varying degrees.The viscosity of fracturing fluid is inversely related to fracture length. When the Poisson ratio of formation rock has no obvious effect on fracture length, the influence of geological and engineering parameters on fracture turning angle is as follows: viscosity, displacement, Young's modulus of rock and Poisson's ratio.The larger the distance between clusters and the stress difference, the smaller the steering angle.In this paper, the extended rule and control mechanism of multi-cluster fracturing fractures in horizontal wells are further revealed. The program can be used to analyze the influence of various factors on fracturing.
【学位授予单位】：西南石油大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TE357

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