3D reservoir simulation of CO 2 injection in a deep saline aquifer of the Lower Paleozoic Potsdam Sandstone of the St Lawrence Platform, Gentilly Block, Quebec

Abstract

Increasing demand in carbon dioxide storage volumes to reduce greenhouse gas emissions to net zero by 2050 implies assessment of CO 2 storage capacity, including deep saline aquifers, even in tight sandstone reservoirs. 3D reservoir simulations of supercritical CO 2 injection were carried out in the Lower Paleozoic Potsdam Sandstone of the St Lawrence Platform (Gentilly Block), Quebec to predict safe CO 2 injection rates, evaluate reservoir pressure build-up in the presence of sealing and permeable faults, and estimate the gas injection cumulative. 3D one-way coupled reservoir–geomechanical modelling helped to analyse the interaction between reservoir pressure build-up and changes in in situ stresses, and estimate the risk of top and bottom seal failure and fault shear-slip reactivation. It is shown that a safe CO 2 injection rate per well for 20 years of continuous injection is estimated to range from 0.7 kg s −1 (22.1 kt a −1 ) to 10 kg s −1 (315.4 kt a −1 ) depending on the porosity and permeability of the Potsdam Sandstone varying from core-derived matrix values to ‘fracture-enhanced’ values. The corresponding injection CO 2 cumulative for 20 years ranges from 432.2 to 6013.5 kt per well. The implementation of a multiple-well injection plan will help to increase the injection CO 2 cumulative, given the considerable thickness and basin-scale dimensions of the Potsdam reservoir (3440 km 3 ).