Large scale CO₂ storage with water production

Abstract

CO₂ storage without water production is realized by injecting CO₂ into the underground without any actions for relieving the pressure buildup generally associated with such an operation. Successfully storing large volumes of CO₂ at a given site with no active pressure relief is not guaranteed due to uncertainty of the size and permeability of the hydraulically connected complex connecting to the gas injectors. With water producers active pressure management is possible, and the volume of produced water liberates corresponding pore volume that is available for storage of CO₂ without any pressure buildup. Also the relevant size of the storage complex is mainly confined to the region between the injectors and producers, thus reducing the amount of uncertain geology involved. In this paper we run 144 generic 5-spot well pattern Eclipse simulations to assess the effect of petrophysical and operational input parameters. It is seen that storage efficiency and gas breakthrough times can be relatively sensitive to the input parameters, highlighting some of the challenges when a planning a real large scale CO₂ storage project. It is also seen that that the 5-spot storage pattern is quite efficient for gas storage, ranging from 9.7% to 62.5% reservoir volume gas per effective pore volume stored at gas breakthrough in the water producer