【作者】 张衍臣；

【导师】 贾振岐；

【作者基本信息】 大庆石油大学 ， 油气田开发工程， 2006， 博士

【摘要】 渗流力学是石油开发的基础学科,随着石油的开发,对于低渗透油田,由于开采方式不同,使得地下流体的流动变得非常复杂,例如间歇采油状况下的地下压降漏斗形态变得不规则;变参数射孔方式下的内边界条件呈现多样性和不确定性等等。在边界形状或地层初始压力分布十分复杂的条件下,渗流力学方程的求解难度增加。为此,本文针对试油试采中的新难题,采用理论推导与实测数据验证相结合的方法,重点研究了低渗透油藏间歇采油(地层压力分布复杂)和射孔(边界条件复杂)时复杂流动条件下的渗流机理。取得如下创新性成果:1、间歇试采井渗流理论对间歇试采生产状态下复杂流动条件的渗流理论进行了研究,建立起符合实际生产条件的渗流物理模型,系统研究并分别求得多种类型井及非均质地层中渗流力学方程的解,给出了这些解的半数值半解析的表达式,解决了由于初始条件的非线性和多脉冲渗流过程造成的求解渗流方程的复杂数学问题(包括求解方法、不同区域网格划分、数值计算方法等),为间歇采油井的试井分析、试井设计和产能评价提供了理论基础;首次提出了采用δ函数方法求解渗流力学方程的思路与方法,计算分析了间歇采油井井底的压力变化特征。通过与实测数据对比,证明了利用δ函数的方法求解间歇试采生产状态下的渗流力学方程是可行的、有效性的。2、射孔复杂内边界的渗流机理对稳定和不稳定渗流条件下影响射孔效果的诸因素进行了深入研究,建立起一套研究复杂射孔条件下流体渗流理论的方法。在曙光大型机上计算了不稳定渗流条件下射孔的三维压力分布、井底压力曲线、井底流量曲线、径向流起始区域等。首次采用不稳定的渗流方程,给出了径向流的起始半径,并对定流量生产、段塞流生产的井底压力进行了计算、分析。在此基础上所设计的优化射孔方案更接近实际生产条件;首次使用并行算法进行各种射孔方式下的井底压力模拟计算。计算结果的分析和比较表明,最终设计的射孔优化方案达到了预期的产率比。更多还原

【Abstract】 Fluid mechanics in porous medium is a basic subject of oil development. In the process of oil development , due to different oil developing methods, flow of formation fluid becomes very complex for low-permeability oilfield . For example, the shape of pressure drop funnel becomes anomalous under intermittent pre-production, and the inner boundary condition under various parameter perforation type shows diversity and uncertainty, and so on. Solution of percolation equation also becomes more difficult when boundary geometry or initial pressure distribution of formation is complex enough. In view of the new problems in well test and pre-production, this thesis focuses on the fluid mechanics of intermittent pre-production (pressure distribution of formation is complex) and casing perforation (boundary condition is complex) at complex flow by integrating theory derivation with test data verification. Main study content and achievement of the thesis is as follows:1. The filtration theory of intermittent production well testingThe filtration theory of complex flow was studied under the condition of intermittent production well testing. The physical model was developed according to the actual producing condition; and the percolation equation solutions were studied systematically and resolved respectively for multiple well types and anisotropic layers. The semi-numerical and semi-analytical expression was obtained, by which, we can deal with very complex mathematics problems due to the initial condition nonlinearity and multi-pulse filtration flow (including the resolution methods, the grid division and numerical methods etc.), providing the theory basis for well testing analysis, design and productivity evaluation of intermittent producing wells. It is the first time that the method and idea ofδfunction was presented to figure out the flow equation and analyze the down-hole pressure. Compared with the field data, it is demonstrated that the method ofδfunction is feasible and effective to resolve the percolation mechanics equation under the condition of intermittent production test.2. Fluid flow mechanics of complex inner boundary condition of perforationThe factors that affect perforation efficiency at steady and transient flow condition are intensively studied, and a series of study methods for fluid percolation theory under complicated perforation is established. It is operated in Shuguang macro computer for 3D pressure distribution, downhole pressure curve, sandface flowrate curve and radial flow initial area, etc under unsteady flow perforation. We first obtain radial flow initial radius by transient flow equation, and analyze downhole pressure of constant flow rate and slug flow production. Therefore, the optimized perforation plan is closer to actual production behavior. Parallel algorithm is first applied in downhole pressure simulation of various perforation types. It is showed by the analysis and comparison with the computational solutions that the ultimate prospective rate of production is achieved in the optimized perforation plan..更多还原