Simple Simulation of Fracturing as a Result of CO₂ Mineral Dissolution and Precipitation

CO₂ sequestration in aquifers or depleted oil and gas fields depends on good injectivity, which is not decreasing over time, to achieve the target storage capacity of the chosen reservoir. Depending on the mineral composition of the rock formation into which CO₂ is planned to be stored, dissolution of certain cement minerals at grain contacts can occur. These minerals are then free to be transported further along connected pores, until they get trapped, either due to constricted pore throats or decreasing velocity field. A simple conceptual model is presented here whereby dissolution and deposition mechanisms are related to the injection velocity, the pore throat size distribution in a feedback loop potentially creating conditions for fractures to occur. Tuning of the chemical processes in terms of timescale compared to the flow velocity and pressure changes leads to different fracture patterns.