有限导流垂直裂缝气井产量计算与数值模拟

发布时间：2018-03-18 10:44

本文选题：气体渗流　切入点：有限导流垂直裂缝　出处：《中国地质大学(北京)》2015年硕士论文　论文类型：学位论文

【摘要】：水力压裂是一种成熟而有效的增产增注措施。由于水力压裂在油气田生产中占有着极其重要的地位,所以一直受到广大学者和油藏工程师们的重视。在低渗透和致密气藏中,许多气井不经过水利压裂不能得到工业气流,不能进行生产。由于天然气压缩性的变化影响非常大,所以不能使用微可压缩假设,导致控制方程具有非线性。即便采用拟函数方法能够将天然气渗流控制方程化简为与微可压缩流体的渗流控制方程同样的形式,但方程中的扩散系数项总是与压力相关的,难以进行精确的解析求解。对这些解析方法指导现场实际生产的可靠性进行验证是必须的。本文选择Hall-Yarborough(1973)方法计算天然气的压缩因子,选择Lee-Gonzalez-Eakin(1966)方法计算天然气的粘度,用物质平衡拟时间方法处理气藏控制方程非线性,利用Laplace变换求解了矩形地层中任意位置处一口直井和有限导流垂直裂缝井的不稳定渗流数学模型,并完成了井壁流量的相应快速计算方法,给出了直井和有限导流垂直裂缝气井的定流压情况下的产量解析解实例计算。用Eclipse数值模拟软件验证了直井解析解与有限导流垂直裂缝井的解析解的准确性。本文还分析了近井网格大小和时间步大小对普通直井数值模拟结果的影响,近井网格大小和裂缝两端网格大小对有限导流垂直裂缝气井数值模拟结果的影响,并讨论了裂缝两端局部加密对多裂缝井数值模拟的影响,给出了相对合理的普通直井和有限导流垂直裂缝井的数值模拟方法。分析研究了裂缝的导流能力和穿透比对不同油藏产量的影响。在文章的最后分析研究了气藏渗透率和裂缝导流能力对最优穿透比的影响规律,气藏渗透率和裂缝穿透比对最优导流能力的影响规律。
[Abstract]:Hydraulic fracturing is a mature and effective measure for increasing production and injection. Because hydraulic fracturing plays an extremely important role in the production of oil and gas fields, it has always been attached importance to by scholars and reservoir engineers. Many gas wells can't get industrial airflow without hydraulic fracturing and can't be produced. Because the change of the compressibility of natural gas is so great, we can't use the supposition of micro-compressibility. The governing equation is nonlinear. Even if the governing equation of natural gas seepage can be simplified to the same form as the governing equation of micro-compressible fluid, the diffusion coefficient term in the equation is always related to pressure. It is necessary to verify the reliability of these analytical methods to guide the actual production. In this paper, we select Hall-Yarborough 1973method to calculate the compressibility factor of natural gas, and Lee-Gonzalez-Eakin1966) method to calculate the viscosity of natural gas. The nonlinear governing equation of gas reservoir is treated by the method of material equilibrium quasi time, and the unsteady seepage mathematical model of a straight well and a vertical fracture well with finite diversion flow at any position in rectangular formation is solved by Laplace transform. The corresponding fast calculation method of wellbore flow is completed. An example calculation of analytical solution of production under the condition of constant flow pressure of straight well and finite diversion vertical fractured gas well is given. The accuracy of analytical solution of straight well and finite diversion vertical fractured well is verified by Eclipse numerical simulation software. The influence of the grid size and time step size of the near well on the numerical simulation results of the ordinary vertical well is also analyzed. The effect of near well mesh size and fracture end mesh size on the numerical simulation results of finite diversion vertical fracture gas wells is discussed, and the effect of local infilling at both ends of fractures on the numerical simulation of multi-fracture wells is discussed. A relatively reasonable numerical simulation method for normal straight wells and finite conductivity vertical fractured wells is given. The effects of fracture conductivity and penetration ratio on the production of different reservoirs are analyzed. At the end of this paper, the gas reservoirs are analyzed and studied. The influence of permeability and fracture conductivity on the optimal penetration ratio, The effect of gas reservoir permeability and fracture penetration ratio on optimal flow conductivity.
【学位授予单位】：中国地质大学(北京)
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TE328

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