Simulations for CO₂ Injection Projects With Compositional Simulator

The need for CO₂ emissions reduction at a large scale globally implies that CO₂ injection into the subsurface be undertaken in a greater variety of geological environments that has been the case previously. Often when the storage reservoirs are saline aquifers, exploration data for proposed injection sites are extremely sparse. The special behaviour of CO₂-water/brine systems (mutual solubility and chemical reactivity) adds complex processes, such as dry-out, salting-out, chemical reactions to the dynamic model. Simulation in these situations is one of few means of assessing an injection site and testing various scenarios. The accurate description of physics and chemistry in numerical simulation tools is fundamental for understanding processes, as well as designing appropriate injection or mitigation strategies.

We present simulations of CO₂ injection into saline aquifers with a fully compositional code that has been expanded and enhanced to include specific phenomena, such as drying-out and salting-out. The examples illustrate the importance of pre-injection studies, as the wrong injection strategy may severely impact injectivity, putting the project in jeopardy.