【作者】 王月；

【导师】 牛建军；

【作者基本信息】 吉林大学 ， 地质工程， 2012， 硕士

【摘要】 对油气田大规模及深入的开发，已经导致整装的、类型相对简单的油气藏几近殆尽，实现油气增产上主要靠寻找新的复杂油气藏和提高老油田油气采收率，九十年代以来，剩余油问题和水驱方向及前缘问题是油气田开发工作中的一个研究热点，也是有关国际会议的重要议题，预测剩余油分布的新方法和新技术亟待研发。文章对几种常用的剩余油监测方法：地震技术、示踪剂监测方法、测井储层描述方法做了简要的介绍，阐述了各自的优势和不足。与其他方法比，电位法监测剩余油具有成本低、效率高、可实施动态监测的优点。该方法是以充电法的原理和地下动态导体的基本理论为依据，通过研究地下注入工作液前后的地表电位的变化，对剩余油的分布及工作液的流动情况做出定量及定性的判断，即在注入工作液的过程中，注入的工作液会减小注入目的层的电阻率，与围岩介质的电阻率有比较大的差异。在该方法的数值模拟中，把总电位分成了正常电位和异常电位，以点电流源电位公式为基础得到了正常电位，用有限差分法得出来异常电位的方程组，利用不完全Cholesky共轭梯度方法求解大型稀疏线性方程组，计算得出了异常电位的表达式，消除了电源附近的奇异性，而且介绍了总电位、正常电位、异常电位的边界条件问题。在正演数值计算方法的基础上，首先将反演问题线性化，然后用光滑约束最小二乘法进行了反演计算，其中雅可比矩阵的计算，从有限差分得出的异常电位公式出发，运用了Tripp提出的灵敏度定律得出雅可比矩阵，避免了多次直接求解该矩阵。运用上面的算法，模拟地表供电、井中供电以及井地供电三种方式，根据正演和反演的模型，得出供电偶极子为井地供电方式时，对模型中设置的目标体探测能力较强，而其它两种供电模式对目标体没有分辨率。为了验证电位法的正确，我们在中原油田做了实验。中原油田的某些区块已经进入高含水开发期，储层的物性、压力场和油水关系等发生了变化，剩余油的分布情况不清楚，并且油田的开发难度越来越大，针对这些难点，我们应用了电位法监测技术，测网布置成矩形，根据测试数据绘制了视电阻率等值线图，并且与该测区的饱和度等值线图做了对比，证实了电位法监测剩余油的可行性。除此之外，我们在新疆的风城油田也进行了试验，采用环形测网，利用电位监测结果进行对比，判断蒸汽的扩散方向和运移规律，得到了满意的效果。更多还原

【Abstract】 The oil and gas reservoir are having sharp reduction, which are exploited easilyand of relatively simple type, with large-scale and in-depth development of oil andgas fields. Increasing production of oil and gas depends mainly on the search for newcomplex reservoir and improve the oil recovery of the old oil fields. Since the1990s,the remaining oil and water flooding on the direction and the leading edge are a hotresearch topic in the oil and gas field development work, they are also about theimportant issues of the International Conference. The new methods and newtechnologies of predicting distribution of remaining oil are in urgent need of researchand development. In the article, there are also brief introductions on several othercommonly used residual oil monitoring methods: seismic techniques, tracermonitoring methods， well logging reservoir description method，and elaboratingtheir respective strengths and weaknesses. Compared with those methods, thepotential method has lower cost, higher efficiency, and dynamic monitoring could beimplemented in this method. The method is based on the law principles ofmise-a-la-masse method and the basic theory of the underground dynamicconductor. To make quantitative and qualitative judgments on the distribution ofresidual oil and the flow of working fluid through studying the change of surfacepotential after injecting the working fluid. In other words, the injected working fluidreduce the resistivity of target layer during injecting working fluid, that leads torelatively large differences to the resistivity of surrounding rock medium.In the method of numerical simulation, the total potential is divided into thenormal potential and abnormal potential, we got the normal potential based onpotential formula of the point current source, and the equations of the abnormalpotential using finite difference method. We applied the incomplete Choleskyconjugate gradient method to solve large sparse linear equations and got theexpression of the abnormal potential to eliminate the singularity near the power source. There are discussions on the boundary conditions of total potential, normalpotential and abnormal potential. Based on forward numerical calculation method，inverse problem was linearized, and then applying the smoothness constraint leastsquares method for the calculation of inversion problem, However, by applying thereciprocity principle, the partial derivatives can be very efficiently obtained withouthaving to directly solve the matrix equations a number of times. The basic idea isdescribed in Tripp et al.（1984） and is known as the sensitivity theorem. Accordingto the above algorithm, we simulated three power supplying ways: surface-surface,borehole-borehole, surface-borehole. From the forward and inversion model,weknow that electric potential method has high detection ability on the target body inmodel when surface-borehole power supplying way was used, no detection abilitywhile the other two power supplying ways.There is an experiment in the Zhongyuan Oilfield to verify that potentialmethod’s result is correct. Some blocks of the Zhongyuan Oilfield have entered thehigh water cut stage, the reservoir’s physical properties, pressure field and oil-waterproportion have been changing, and it is not clear about the distribution of residualoil, and exploiting the oil fields more and more difficult. Because of those difficulties，we apply the potential method in these blocks, we got the apparent resistivitycontour maps drawn according to the test data, and they are compared with thesaturation of contour map, we got this conclusion that the potential method can beused for monitoring residual oil. In addition, we also carried out test in the WindyCity Oilfield in Xinjiang using ring measured net. Potential monitoring results werecompared to determine the direction of the proliferation and migration law of thesteam, and we get satisfactory results.更多还原