基于对苏北盆地盐城组下段沉积旋回地层概化,建立了一个含有断层的二维剖面模型,采用TOUGH2/ECO2N程序对注入到深部咸水层中CO2的运移分布特征及沿断层的泄漏过程进行了数值模拟.结果表明,尽管盐城组下段地层具有3层旋回结构且砂岩层属高孔高渗储层,但由于泥层厚度较小且渗透率相对较高,多层封盖效果不佳.在存在导通断层时,CO2泄露风险较大.应用Morris法以断层中气相CO2总量作为输出变量,对模型参数进行了全局敏感性分析.研究显示,当仅改变断层参数时,与毛细压力相关的参数对气相CO2沿断层泄漏影响程度最高；当考虑系统参数整体变化时则以砂岩含水层和泥岩的渗透率敏感性最高,其次为与毛细压力相关的参数(进气压力、残余液体饱和度及孔隙分布指数).两种情形下孔隙度与盐度的敏感性均很小.%TOUGH2/ECO2N code was used to simulate transportation of CO2 plume in the deep saline aquifer of lower part of the Yancheng Formation in Subei basin. A fault was added to the conceptual model to evaluate the leakage risk after CO2 injection. Simulation results indicate that the effect of multilayer capping for CO2 sequestration is not good because of the clay strata with small thickness and relatively high permeability, although the lower part of the Yancheng Formation has three sequences' structure (multiple sand-clay layers) and the sand stratum has high permeability and high porosity. Especially when there is a fault conducting all layers the leakage risk for CO, geological sequestration is significant. Morris method was used to analyze the global sensitivity of the parameters for two scenarios. When only the fault parameters are changed, the parameters related with the capillary pressure have great effect on CO2 leakage along the fault. When all the parameters of fault, sand and clay strata are varied, the permeability of sand and clay has the highest sensitivity for the leakage risk, while the parameters related with the capillary pressure are secondary. For both scenarios, the sensitivity of porosity and salinity is very small.
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