多段压裂水平井复杂渗流理论与试井分析研究

发布时间：2018-10-20 06:56

【摘要】：能源是人类活动的物质基础,不断攀升的能源需求和日益增大的能源压力,使得一些难开发的油气资源(如致密砂岩油气藏、多重介质碳酸盐岩油气藏、页岩气藏等)越来越受到重视。由于这些油气资源储层低孔、低(特低)渗、渗流阻力大、连通性差,若用直井和水平井开采,则无法满足高效开发的需要；若进行水平井多段压裂措施改造,产生多条裂缝,增大泄油面积,可有效提高产能,因此,多段压裂水平井已成为一种必然选择。目前,国内外水平井多段压裂工艺技术已日趋成熟,该技术已在国内大部分油田进行了广泛的应用,然而,其基础渗流理论研究相对滞后,对多段压裂后裂缝网络渗流规律与井底压力动态变化规律认识不清,导致该类油气藏水平井多段压裂后如何高效开发缺乏理论依据。从渗流力学基本原理出发,根据致密砂岩油气藏、多重介质碳酸盐岩油气藏和页岩气藏储层实际地质特征,且充分考虑压裂裂缝呈非等间距、非等半长、非等缝高、非等任意倾角的实际情况,建立了一系列多段压裂水平井渗流物理数学模型；并研究了一种求解多段压裂水平井渗流模型的新方法(包括利用点源函数理论、三维特征值法、拉普拉斯变换、正交变换等数学方法),获得了井底压力动态解；再利用计算机编程绘制了新型的试井理论样版曲线,同时分析了井参数、裂缝参数以及储层参数的敏感性特征。主要的研究模型有：①致密砂岩油气藏(无限导流裂缝、有限导流裂缝和2区线性复合)多段压裂水平井渗流物理数学模型(共3个)。②多重介质碳酸盐岩油气藏(裂缝型、孔洞型和裂缝孔洞型)多段酸压水平井渗流物理数学模型(共7个)。③页岩气藏(拟稳态扩散、非稳态扩散和2区线性复合)多段压裂水平井渗流物理数学模型(共3个)。最后,形成了一套系统的多段压裂水平井复杂渗流理论与试井分析方法,并做了4口现场实例多段压裂水平井的拟合解释,获得了有用的油气藏参数以及压裂裂缝参数。研究成果将为致密砂岩油气藏、多重介质碳酸盐岩油气藏、页岩气藏等提供新的渗流模型,促进地下渗流力学理论的发展,为水平井多段措施改造后的高效开发奠定理论基础。
[Abstract]:Energy is the material basis of human activities. The increasing energy demand and increasing energy pressure make some difficult oil and gas resources (such as tight sandstone reservoir, multi-medium carbonate reservoir). Shale gas reservoirs, etc.) are getting more and more attention. Because of the low porosity, low permeability, high seepage resistance and poor connectivity in these oil and gas resource reservoirs, it is impossible to meet the needs of high efficiency development if the production of vertical wells and horizontal wells is used, and if multiple fracturing measures are carried out in horizontal wells, many fractures will be produced. Increasing oil discharge area can effectively increase productivity, so multistage fracturing horizontal well has become an inevitable choice. At present, the multi-stage fracturing technology of horizontal wells at home and abroad has become more and more mature, and the technology has been widely used in most oil fields in China. However, the research on the basic seepage theory is lagging behind. It is not clear to understand the percolation law of fracture network and the dynamic change law of bottom hole pressure after multistage fracturing, which leads to the lack of theoretical basis on how to develop effectively after multistage fracturing in horizontal wells of this kind of reservoirs. Based on the basic principles of percolation mechanics, according to the actual geological characteristics of tight sandstone reservoirs, multi-medium carbonate reservoirs and shale gas reservoirs, the fracturing fractures are considered to be non-equidistant, non-equal-length and non-equifracture height. In this paper, a series of physical mathematical models of percolation in multistage fracturing horizontal wells are established, and a new method to solve the percolation model of multistage fracturing horizontal wells is studied (including point source function theory, 3D eigenvalue method, etc. Laplace transform, orthogonal transformation and other mathematical methods are used to obtain the bottomhole pressure dynamic solution, and then a new type of well test theory sample curve is drawn by computer programming, and the sensitivity characteristics of well parameters, fracture parameters and reservoir parameters are analyzed at the same time. The main research models are as follows: (1) the physical mathematical model of percolation in multi-section fracturing horizontal wells (3), (2) carbonate reservoirs with multiple media (fracture type), (2) tight sandstone reservoirs (infinite diversion fractures, finite conductivity fractures and linear complex of area 2). (3) physical mathematical models of multi-stage fracturing horizontal well percolation (7) and (3) shale gas reservoir (quasi-steady diffusion, unsteady-state diffusion and linear complex in zone 2) multi-stage fracturing horizontal well percolation physical mathematical model (3). Finally, a set of systematic complex percolation theory and well test analysis method for multi-stage fracturing horizontal wells are formed, and the fitting interpretation of multi-stage fracturing horizontal wells in 4 field examples is made, and useful reservoir parameters and fracturing fracture parameters are obtained. The research results will provide a new percolation model for tight sandstone reservoirs, multi-medium carbonate reservoirs and shale gas reservoirs, promote the development of underground percolation mechanics theory, and lay a theoretical foundation for the highly efficient development of horizontal wells after multi-stage measures.
【学位授予单位】：西南石油大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：TE312

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