The fluid mobilities and the lateral extent of the CO₂ plume and the dry-out zone are among important unknowns required to effectively manage CO₂ storage in saline aquifers projects. These unknowns can be derived from pressure falloff testing which has been widely used to characterize the subsurface. This work provides a three-region analytical solution for falloff pressure during the infinite-acting period of CO₂ injection in saline aquifers. The solution is derived using Laplace transformation technique of the governing diffusivity equations and the accompanying initial and boundary conditions. The exact solution is validated against numerical results obtained from a black-oil reservoir simulator for two cases. The solution is approximated into simple forms in real-time domain considering different time periods. Then, a graphical semi-log analysis technique based on the approximate solutions is provided as an interpretation tool of falloff tests where the fluid mobilities and the extents of dry-out zone and CO₂ plume can be inferred. The interpretation technique is applied to synthetic falloff test data to investigate its potential and reliability.

有效地管理盐水蓄水层项目中的CO ₂储存所需的重要未知因素包括CO ₂羽流和干燥区的流体流动性和横向范围。这些未知数可以从压力下降测试中得出，该测试已广泛用于表征地下特征。这项工作为CO ₂无限作用期间的降压提供了一个三区域分析解决方案注射生理盐水。使用控制扩散系数方程的拉普拉斯变换技术以及相应的初始条件和边界条件来推导该解。针对两种情况，根据从黑油储层模拟器获得的数值结果验证了确切的解决方案。考虑到不同的时间段，该解决方案在实时域中近似为简单形式。然后，提供了基于近似解的图形半对数分析技术，作为衰减测试的解释工具，可以推断出流体的流动性以及变干区和CO ₂羽流的程度。解释技术应用于合成衰减测试数据，以研究其潜力和可靠性。