Abstract
This article discusses the problem of creating a hydrogen storage in an aquifer. It is assumed that the process of hydrogen injection and the life cycle of its storage should provide the most complete reverse production of the injected gas in a few years. The features of injected gas distribution in an aquifer are considered, taking into account a number of parameters. For example, the effects of gas breaking through a cap rock and fluids migration under influence of natural water flows from aquifers associated with the target reservoir. An effective storage and subsequent production system are proposed allowing to control geometry and volume of gas bubble in the reservoir.
The results are obtained on the basis of large-scale 3D geological and hydrodynamic modeling of filtration through porous medium of a multicomponent system in the form of hydrogen, methane and water mixture on synthetic 3D models. Corresponding studies were performed on a certified hydrodynamic simulator using a composite model.
Large-scale 3D geological and hydrodynamic modeling made it possible to justify the method of compact hydrogen storage in an aquifer. Closed systems, without contact with large volumes of water in adjacent aquifers, do not allow significant gas volumes to be stored under technologically realistic parameters. Presence of an active aquifer dramatically changes injected gas configuration and facilitates its migration from the zone of possible reverse production.
The necessity of creating a permanently operating associated water injection system is substantiated to control geometry of the created hydrogen storage together with methane. It is shown that without controlled injection of water, both at the stage of creating the storage and at the stage of storing hydrogen, it is not possible to ensure its subsequent sufficiently complete production to the surface in a reasonable time with technologically justified costs. Otherwise hydrogen reserves are being scattered due to gas migration over very large distances from gas injection wells. Strong influence of the aquifer system parameters associated with the target reservoir is illustrated for dynamics of hydrogen propagation.
