Capturing the coupled hydro-mechanical processes occurring during CO2 injection – example from In Salah

Abstract

At In Salah, CO2 is removed from the production stream of several natural gas fields and re-injected into a deep and relatively thin saline formation, in three different locations. The observed deformation on the surface above the injection sites have partly been contributed to expansion and compaction of the storage aquifer, but analysis of field data and measurements from monitoring has verified that substantial activation of fractures and faults occur. History-matching observed data in numerical models involve several model iterations at a high computation cost. To address this, a simplified model that captures the key hydro-mechanical effects, while retaining a reasonable accuracy when applied to realistic field data from In Salah, has been derived and compared to a fully resolved model. Results from the case study presented here show a significant saving in computational cost (36%) and a computational speed-up factor of 2.7.