基于数字岩心技术碳酸盐岩储层电性特征研究

发布时间：2018-07-07 15:11

本文选题：数字岩心 + 碳酸盐岩　；参考：《长江大学》2017年硕士论文

【摘要】：现今世界的油气总产量的60%都存在于碳酸盐岩储层中。碳酸盐岩储层的测井响应受岩石的孔隙空间结构、孔隙流体性质及分布等因素的影响。岩石物理实验是传统的研究碳酸盐岩导电性质的重要手段,但是其存在费用高、周期长的特点,并且在裂缝型储层中存在具有裂缝的代表性岩心取心困难问题。利用数字岩心技术可以辅助解决上述问题。本文基于X-CT扫描的碳酸盐岩三维数字岩心,利用数学形态法中的膨胀和溶蚀运算模拟碳酸盐岩溶蚀孔、洞的扩大和缩小;利用数学形态法中的闭运算模拟岩心中的流体分布;利用分数布朗运动建立各种不同宽度和角度的裂缝形态模型。然后基于建立的不同孔、洞和裂缝形态的碳酸盐岩数字岩心模型,利用有限元法开展储层的电性特征模拟。其中主要有两部分研究内容:孔、洞型碳酸盐岩储层电性特征研究和裂缝型储层电性特征研究。对于溶蚀孔、洞型碳酸盐岩,主要研究了储层中的孔隙度、地层水矿化度、润湿性和饱和度对碳酸盐岩的导电性的影响。结果表明:在利用多块岩样进行岩石物理实验时,所得到的碳酸盐岩储层的地层因素与孔隙度的关系和岩样的孔隙度大小无关,而与孔隙形态有关;碳酸盐岩储层中的饱和度指数是随着含水饱和度的增加而变化的。因此,在计算碳酸盐岩储层的饱和度时,阿尔奇公式更加适用于含水饱和度大于60%的储层;在水湿岩石中,水相主要充填着小孔隙,而油相则充填着大孔隙,所以相比较于油湿具有更多的导电通道,导电性更好。因此,在利用阿尔奇公式计算含水饱和度时,确定岩石的润湿性非常重要。对于裂缝型碳酸盐岩,主要研究了不同宽度和角度的裂缝对储层导电性的影响。结果表明:在裂缝型碳酸盐储层中,随着总孔隙度的增加,平行于裂缝延伸方向的胶结指数降低、饱和度指数增加,而垂直于裂缝延伸方向的胶结指数升高、饱和度指数减小;裂缝型碳酸盐岩储层导电性受裂缝角度影响非常大,而且各向异性较强,所以相同岩样不同方向上的电导率差异非常大。通过对建立的溶蚀孔、洞型和裂缝型碳酸盐岩岩心的数值模拟,得到并分析了不同孔、缝结构和不同流体分布下的导电特征,分析了阿尔奇公式在碳酸盐岩储层中的适用条件,对碳酸盐岩储层的导电性研究具有非常重要的指导意义。
[Abstract]:60% of the world's total oil and gas production is present in carbonate reservoirs. The logging response of carbonate reservoir is affected by pore space structure, pore fluid properties and distribution. Rock physics experiment is an important means to study the electrical conductivity of carbonate rock, but it has the characteristics of high cost and long period, and it is difficult to coring in fractured reservoirs. Digital core technology can be used to solve the above problems. In this paper, based on the X-CT scanning carbonate rock three-dimensional digital core, the expansion and dissolution operations in the mathematical morphology method are used to simulate the expansion and shrinkage of the cavern, and the closed operation in the mathematical form method is used to simulate the fluid distribution in the core. The fracture morphology models with different widths and angles are established by fractional Brownian motion. Then, based on the digital core model of carbonate rock with different pore, hole and fracture morphology, the electric characteristics of reservoir are simulated by finite element method. There are two main parts of the study: pore, cavern carbonate reservoir electrical characteristics and fracture reservoir electrical characteristics. The effects of porosity, formation water mineralization, wettability and saturation on the conductivity of carbonate rocks are studied. The results show that the formation factors of carbonate reservoir are independent of porosity and porosity, but are related to pore morphology. The saturation index in carbonate reservoir varies with the increase of water saturation. Therefore, when calculating the saturation of carbonate reservoir, Archie formula is more suitable for reservoirs with water saturation greater than 60%. In wet rock, the water phase is mainly filled with small pores, while the oil facies is filled with macropores. So compared with oil wet has more conductive channels, conductivity is better. Therefore, it is very important to determine the wettability of rock when using Archie formula to calculate water saturation. For fractured carbonate rock, the influence of different width and angle of fracture on reservoir conductivity is studied. The results show that in fractured carbonate reservoirs, with the increase of total porosity, the cementation index parallel to the fracture extension direction decreases, the saturation index increases, while the perpendicular to the fracture extension direction increases, and the saturation index decreases. The conductivity of fractured carbonate reservoir is greatly influenced by fracture angle and anisotropy, so the conductivity of the same rock sample in different directions is very different. Based on the numerical simulation of the corrosion pore, cavity type and fracture type carbonate core, the conductive characteristics of different pore, fracture structure and different fluid distribution are obtained and analyzed, and the applicable conditions of Archie formula in carbonate reservoir are analyzed. It is very important to study the electrical conductivity of carbonate reservoir.
【学位授予单位】：长江大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：P618.13

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