【作者】 陈亮；

【导师】 张中庆；

【作者基本信息】 浙江大学 ， 电磁场与微波技术， 2008， 硕士

【摘要】 双侧向测井是电阻率测井方法中使用最广泛的方法之一,可以有效的评价地层的孔隙度和含油气饱和度及其产能,为油气藏的描述和油田地质情况的研究以及油层岩性的确定提供参考资料。针对当前石油勘探开发过程中水平井和斜井应用的实际需求,按照双侧向测井仪器模型和工作方式,文章利用三维有限元方法成功模拟双侧向测井仪器在斜井和水平井中的响应,得到测井仪器在地层中的响应曲线,进而获得地层的电阻率分布,为斜井和水平井相应的解释工作提供参照根据。本文的创新点是采用三维网格加密技术完善了程序模拟复杂地层的能力,应用高阶基函数并结合优化后的边界条件,提高了三维有限元素法的计算效率和精度;本文提出的新算法同传统的三维有限元素法相比,能够在相同精度情况下,可以将计算效率提高一个数量级。在第一章绪论部分,描述了本文的研究背景和国内外研究现状,并且对有限元素法进行了简单描述并给出了本文的主要研究贡献。在第二章中,介绍了双侧向测井仪器的仪器的结构和工作原理。在第三章中详细论述了利用有限元法进行双侧向测井数值分析的过程,从双侧向测井中电场满足的微分方程式出发,给出泛函表达式和边界条件,经过离散化求解泛函的极值达到求解边值问题。文中详细给出了网格划分和边界处理方法,最后通过前线解法求刚度矩阵,得到深浅侧向监督电极上的电压从而求出深浅侧向的仪器响应。文章通过改进网格划分方法,实现了斜井水平井多地层和侵入偏心模型的构造,提高了程序处理复杂地层的能力;通过改进电极处理方法,成功模拟B电极对测量结果和电流线分布的影响,定量的给出B电极对测量结果的影响。在第四章中,针对三维有限元方法中线性插值基函数影响仿真效率和精度的问题,采用高阶基函数,使得在相对稀疏的网格下就可以得到具有较高精度的仿真结果,不仅节省了计算时间,而且还提高了程序的仿真精度,并且通过改进深侧向边界的处理条件,改进了深侧向结果的精确度。第五章针对测井工作所遇到的常见地层和环境条件,开展了一系列模拟计算,对影响双侧向测井仪器响应的参数进行了详细研究。分析仪器不同几何结构对结果的影响;斜井中,通过分析不同角度对仪器响应结果的影响,给出了特定地层中的斜井的围岩校正图板;在水平井中通过分析地层中侵入、围岩、目的层等对仪器响应结果的影响,并制作了特定地层中的井孔上下距离校正图板、侵入校正图板和围岩层厚校正图板。最后给出了本论文的总结和工作展望。作为本课题研究成果,三维有限元双侧向测井仿真程序能够快速仿真计算测井曲线,可用于解释石油测井曲线。更多还原

【Abstract】 Lateral logging is one of the most popular methods in resistivity well logging, it is widely used to evaluate the porosity and saturation of oil and gas and its production. And can be used to give the description of reservoir and geological conditions and lithology of oil.For the application of horizontal wells and deviate wells in the well logging process, the author simulations Lateral logging equipment response in deviate and horizontal well according to the mode it works by using three dimension finite element method. By using this method, We can get the equipment response curve and resistivity distribution of stratum, it helps to give the interpretation of logging. The innovation of this paper is adopt the remesh method to build model precisionly and in order to modeling dual laterolog response efficiently and accurately, high order basis function is adopted. The results show it has higher efficiency and precision compared with linear basis function. The architecture of this paper as follows:The research of lateral logging domestic and abroad is given in chapter 1, and so is the finite element method and the main contribution of this paper.In chapter 2, the mode of lateral logging equipment is given is given.In chapter 3, the author discusses the process of numerical analysis of the lateral well logging using finite element method in detail. First of all, base the principle of finite element method, differential equations which the field of logging obeys is given, from which gives functional expression and boundary condition, finally, using frontal method to solve stiffness matrix and get the monitor electrode voltage, so we can get the deep and shallow equipment response. By improving the mesh method, multiple stratum in horizontal well and invaded eccentricity can be exitly modeled. the B-electrode also in consideration, results show that it will impact the deep lateral logging result and current.In chapter 4, the auther improves process of simulation of lateral logging. In order to modeling lateral logging response efficiently and accurately, high order basis function is adopted. it shows the higher efficiency and precision compared with linear basis function. Furthermore, the anther optimized the mesh and the boundary condition to reduce the error caused by them.In chapter 5, many simulation results in common environmental condition are given for research of response of lateral logging. By simulation the different electrode, different results and different electrode constant are given. Many conclusion and bed thinkness correction are given in deviate well with different angle and different condition; In horizontal well, different layer and invation is analysised and response curves are given, invasion correction chart and bed thickness correction chart are alse made.Finally, the summarization and expectation of this paper is given. As one of the result of this research, the program of simulating the response of laterolog using 3D finite element method can give result quickly and exitly, it can be help to judge the interpretation of well logging response. The resistivity distribution of stratum which gotten by simulation is an important parameter in interpretation course. The results of this research have good prospects in logging interpretation.更多还原