中文摘要：

在“无限大”深部咸水层的二氧化碳（CO2）地质储存数值模拟中，往往需要人为给定一个边界。边界范围大小和类型选取直接影响模拟结果，进而导致储存潜力评价误差。笔者基于典型深部咸水层的二维径向模型，采用TOUGH2-MP软件进行数值模拟，分析了不同边界范围和类型对深部咸水层中注入CO2后压力和CO2饱和度分布、最大压力和CO2运移距离及储存形式和储存效率的影响。为了说明边界的确定与深部咸水层参数有关，还进行了渗透率、孔隙度、压缩系数、温度、盐度和边界类型的敏感性分析。结果表明在隔水边界类型下，边界范围越大，压力增量和CO2饱和度越被“平均化”，从而最大压力增量越小，CO2饱和度分布形状越扁平，最大运移距离越大。但储存形式受边界影响不大，体积储存效率在“无限大”深部含水层中被高估。随着边界范围的扩大，边界引起的差异逐渐变小。另外，基于单相流和多相流解析解理论，得到了在已知注入速率下边界范围大小的简单近似确定方法。该方法考虑CO2的最大运移距离和水相的影响边界两个方面，适用于“无限大”深部咸水层单井或多井注入的边界确定。

英文摘要：

The extent and type of boundary directly affect numerical simulation results of CO2 geological sequestration in ＂infinite＂ deep saline aquifers thereby causes evaluation error of storage potential. In this paper, a typical 2D radial flow model is employed to analyze the effects of the extent and type of boundary on pressure buildup and CO2 saturation plume distribution, the maximum pressure buildup and CO2 migration distance after injecting CO2 into the deep saline aquifer using TOUGH2-MP software. To illustrate the relation between boundary effects and formation parameters, sensitivity analyses for permeability, compressibility, temperature, salinity, and boundary type are performed. The results indicate that the greater boundary extent leads to the more ＂average＂ pressure buildup and CO2 saturation, the smaller maximum pressure buildup, the more flat CO2 saturation distribution shape and the greater CO2 migration distance under no-flow boundary condition. But the boundary effects on storage forms are very small and the volume storage efficiency in the ＂infinite＂ deep saline aquifer is overestimated. The difference becomes smaller and smaller with the expansion of the boundary extent. In addition, according to analytical theory of single-phase and muhiphase flow, one simple approximate analytical method for determining the boundary extent under a known injection rate is obtained. This method is applicable to boundary extent determination for single well or multi-well injection in the ＂infinite＂ deep saline aquifer and the maximum CO2 migration distance and effect boundary of single water phase is taken into account.