盐穴储气库腔底堆积物空隙体积研究

发布时间：2018-03-07 20:35

本文选题：盐穴储气库　切入点：堆积空隙率　出处：《西南石油大学》2015年硕士论文　论文类型：学位论文

【摘要】：盐岩溶腔作为储气库具有重要的现实与战略意义,但我国的盐岩具有层状分布、泥质夹层较多、不溶杂质含量较高等特点,在溶腔结束后腔底会存在较厚的堆积不溶物,不溶物的堆积及内部卤水占据了大量库容,因此有必要对堆积体空隙体积进行评价研究,掌握完腔井腔体容积损失情况,从而为后续注气排卤扩容工艺提供坚实的理论基础。本文在水溶实验后进行不溶物组成及分布分析,并对堆积体空隙率实验测试及仿真模拟得到各层位不溶物的堆积空隙率,在此基础上对现有的堆积模型进行评价及修正研究,进而得出根据现场测井解释成果进行堆积空隙体积计算的方法,预测注气排卤扩容体积。通过研究取得以下认识： (1)根据现场的盐岩样品进行模拟水溶实验,测定了堆积体粒径及粒径分布,研究表明粒径分布符合分形分布。研究发现粒径分布的分形维数D与溶解度成线性关系,因此可以用分形维数来表征不同难溶物下的粒径特征。 (2)通过气体膨胀法测定了单一粒径及不同粒径分布的空隙率,结果表明不同粒径砂石分布的空隙率比单一粒径小；卤水对堆积空隙率的影响实验表明,卤水使较小颗粒堆积空隙率增大,但对较大粒径的空隙率影响不大。模拟注气排卤实验表明,排卤后空隙率比无水堆积体空隙率小,说明堆积体存在束缚水。 (3)基于离散元方法对腔底堆积体的颗粒进行仿真模拟,仿真模拟堆积体总体粒径堆积体空隙率为36.41%；仿真模拟不同分形维数的各组堆积体空隙率,研究表明分形维数和空隙率成线性关系,随着分形维数的增加,模拟空隙率随之下降。 (4)对实验中不同粒径分布样品进行堆积模拟,模拟和实验结果对比表明空隙率存在差别,原因在于理论不能模拟不规则形状颗粒。由此求出实验样品的形状因子为1.184,盐岩样品总体不溶物颗粒修正后的实际值为43.11%。 (5)在实验和模拟的基础上对各种堆积模型进行评价,研究表明通过分形模型,可根据样品的溶解度较准确的表征其堆积空隙率；对可压缩性模型(CPM)根据实测小颗粒数据修正了体系的压实指数K为4.03,计算出仿真粒径的空隙率,与仿真模拟结果吻合,表明CPM模型计算也较准确。 (6)基于分形模型和CPM模型得出堆积体空隙率的现场应用计算方法,结合测井数据对不溶物堆积体进行空隙率计算,CPM计算结果比分形法略小(分形为45.76%,CPM为48.23%),对比现场计算数据(42.66%)进行对比分析,并根据空隙率对注气排卤扩容体积进行预测研究。
[Abstract]:The salt karst cavity is of great practical and strategic significance as a gas storage reservoir. However, the salt rock in China has the characteristics of stratified distribution, more muddy intercalation and high content of insoluble impurities, and there will be a thicker accumulation of insoluble matter at the bottom of the cavity after the end of the cavity. The accumulation of insoluble matter and the internal brine occupy a large amount of storage capacity, so it is necessary to evaluate and study the void volume of the accumulative body, to master the volume loss of the cavity in the cavity well, so as to provide a solid theoretical basis for the subsequent gas injection and halogenation expansion process. In this paper, the composition and distribution of insoluble matter are analyzed after the water solubilization experiment, and the stacking porosity of each layer is obtained by the experimental test and simulation of the porosity of the accumulation body. On this basis, the existing stacking models are evaluated and revised. Furthermore, the method of calculating the volume of stacked voids based on the field logging interpretation results is obtained, and the volume expansion of gas injection and expulsion of halogen is predicted. The following understandings are obtained through the research:. 1) based on the simulated water solution experiment of salt rock samples in the field, the particle size and particle size distribution are measured. The results show that the particle size distribution accords with the fractal distribution. It is found that the fractal dimension D of the particle size distribution has a linear relationship with the solubility. Therefore, fractal dimension can be used to characterize the particle size characteristics of different insoluble materials. (2) the porosity of single particle size and different particle size distribution was measured by gas expansion method. The results show that the porosity of sand and stone with different particle size distribution is smaller than that of single particle size, and the effect of brine on stacking porosity is shown by experiments. Brine increases the porosity of the smaller particles, but has little effect on the porosity of the larger particle size. The results of simulated gas injection test show that the porosity after the removal of halogen is smaller than that of the anhydrous accumulator, indicating that there is bound water in the deposit. Based on the discrete element method (DEM), the particle size of the accumulator is simulated, the porosity of the aggregate is 36.41, and the porosity of each group of accumulators with different fractal dimensions is simulated. It is shown that the fractal dimension is linearly related to the porosity, and the simulated porosity decreases with the increase of the fractal dimension. (4) the piling simulation of samples with different particle size distribution was carried out. The comparison between the simulation and the experimental results showed that there were differences in the porosity of the samples. The reason is that the shape factor of the experimental sample is 1.1844 and the real value after the modification of the total insoluble particles of the salt rock sample is 43.11 because the irregular shape particle can not be simulated theoretically. 5) on the basis of experiment and simulation, various stacking models are evaluated. The results show that the fractal model can accurately characterize the stacking porosity according to the solubility of the sample. For compressibility model, the compaction index K is 4.03 based on the measured small particle data, and the porosity of the simulated particle size is calculated, which is consistent with the simulation results, which indicates that the calculation of CPM model is more accurate. (6) based on fractal model and CPM model, the field application calculation method of accumulation voidage is obtained. Based on the well logging data, the porosity of insoluble accumulations is calculated and the result of CPM calculation is slightly smaller (the fractal is 45.76 CPM is 48.23g, and the field calculation data is 42.66), and the volume of gas injection discharge halogen expansion is predicted according to the voidage.
【学位授予单位】：西南石油大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TE972

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