应用数字岩心技术模拟高温高压气水渗流

发布时间：2018-01-19 22:53

本文关键词： 数字岩心高温高压气水相渗水驱气　出处：《西南石油大学》2017年硕士论文　论文类型：学位论文

【摘要】：气水相渗是气田开发中的重要基础数据,然而模拟地层高温高压真实气水相渗测试往往耗时长、费用高、操作难度大,实验成功率低,因此目前的气水相渗一般是依据标准SY/T5345-2007《岩石中两相流体相对渗透率测定方法》在实验室条件下应用压缩空气或氮气和地层水(注入水)或标准盐水采用稳态法或非稳态法岩心驱替实验获得,未考虑地层高温高压的影响,这与实际地层条件下的渗流条件存在较大的差异。近几年来,数字岩心技术在石油行业的应用越来越多,相比于传统的实验室岩心驱替实验而言,数字岩心技术具有模拟耗时少,获得数据便捷,同一块岩心可在不同温度不同压力下同步进行模拟,并重复模拟等等优点,因此利用数字岩心技术模拟获得地层高温高压真实气水相渗不失为一种有效的方法。然而就目前的报道来看,还未有人将传统的数字岩心模拟技术应用于模拟高温高压气水相渗,已有的研究仅限于常规气水相渗的模拟。由于储层岩石深埋在地下,普通的模拟环境不符合现场的工程实际性,且目前还没有一套把建造三维模型和渗流模拟结合起来的具体方法。本文正是基于以上考虑,自主构建了一整套建立数字岩心、模拟高温高压气水渗流的方法流程,并结合实验室数据对比,论证了使用数字岩心模拟代替实验室实际测试的可行性。将气相质量方程和水相质量方程推导为一个矩阵方程,完美融合在有限元计算软件COMSOL中,考虑高温高压条件对流体物性参数的影响,从而得到不同的模拟结果。通过本文的研究主要得到了以下认识:1.利用AVIZO计算岩石物性参数,得到了与实际测试结果相一致的岩石孔渗数据,且当计算机达不到内存需求时,可分段求取绝对渗透率后再进行算术平均;2.对数字岩心进行修复处理的过程,需要大量时间并结合导入COMSOL的反馈信息后进行人工修复,否者很难导入成功;3.无论从实验测试或者是模拟计算所得到的常温常压与高温高压条件下的气水相渗结果均存在差异:等渗点处含水饱和度在高温高压条件下更小,其相对渗透率更低,相比于常温常压条件,高温高压条件下的两相共渗区域更狭窄;4.两种不同条件下气水相渗的模拟结果与实验室测试结果基本一致:等渗点的位置基本一致,束缚水饱和度相同,束缚水饱和度下的气相相对渗透率相同,残余气饱和度相同;5.建立了一套可行的高温高压模拟操作方法,只需要岩石的孔渗参数,流体在特定温度压力下的物性参数和残余水、残余气饱和度等基础数据,再设定合适的边界条件,就可计算出该岩样的相渗曲线。
[Abstract]:Gas-water phase permeability is an important basic data in gas field development. However, the real gas-water phase permeability test of simulated formation at high temperature and pressure often takes a long time, high cost, difficult to operate, and low success rate of experiment. Therefore, the current gas-water phase permeability is generally based on the standard SY/T5345-2007 < method for determining the relative permeability of two-phase fluids in rocks ". Under laboratory conditions, compressed air or nitrogen gas and formation water (. Injection water) or standard brine is obtained by core displacement experiment by steady or unsteady method. The influence of high temperature and high pressure is not taken into account, which is different from the actual seepage condition. In recent years, digital core technology has been applied more and more in petroleum industry. Compared with the traditional laboratory core displacement experiments, digital core technology has the advantages of less simulation time, easy to obtain data, the same core can be simultaneously simulated at different temperatures and different pressures. And repeated simulation and other advantages, so the use of digital core technology to simulate the formation of high-temperature and high-pressure real gas-water infiltration is an effective method. However, from the current report. The traditional digital core simulation technology has not been applied to simulate the high temperature and high pressure gas-water phase permeability, but the existing research is limited to the conventional gas-water permeability simulation, because the reservoir rock is buried deep underground. The common simulation environment does not accord with the field engineering reality, and there is no concrete method to combine the construction of three-dimensional model and seepage simulation. This paper is based on the above considerations. A whole set of methods to establish digital core and simulate gas-water seepage at high temperature and high pressure were constructed independently and compared with laboratory data. The feasibility of using digital core simulation to replace the actual laboratory test is demonstrated. The gas phase mass equation and the water phase mass equation are derived into a matrix equation, which is perfectly integrated into the finite element calculation software COMSOL. Considering the influence of high temperature and high pressure on the physical parameters of the fluid, different simulation results are obtained. Through the research of this paper, the following understandings are obtained: 1. Using AVIZO to calculate the physical parameters of rock. The rock porosity and permeability data are obtained in accordance with the actual test results, and when the computer fails to meet the memory requirements, the absolute permeability can be calculated in stages and then the arithmetic average can be carried out. 2. The process of repairing digital core needs a lot of time and the feedback information of COMSOL to carry on manual repair, which is difficult to import successfully; 3. The results of gas-water phase infiltration under normal temperature and high pressure are different from those obtained from the experimental test or simulation calculation: the water saturation at the equiosmotic point is smaller under the condition of high temperature and high pressure. Its relative permeability is lower, compared with the normal temperature and atmospheric pressure, the two-phase co-permeation area is narrower under the high temperature and high pressure conditions. 4. The simulation results of gas-water phase infiltration under two different conditions are basically consistent with the experimental results: the position of the equiosmotic point is basically the same, the irreducible water saturation is the same, and the gas phase relative permeability under the irreducible water saturation is the same. The residual gas saturation is the same; 5. A set of feasible operation method of high temperature and high pressure simulation is established, which only needs the basic data such as pore and permeability parameters of rock, physical parameters of fluid under specific temperature and pressure, residual water, residual gas saturation and so on. By setting appropriate boundary conditions, the permeability curve of the rock sample can be calculated.
【学位授予单位】：西南石油大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TE31

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