Pressure evolution in deep saline aquifers during CO2 injection: A method to control high pressure buildup

Production of saline formation water from the storage formation in sufficient amount helps to control the pressure increment during CO₂ storage in saline aquifers. In this paper, we present an engineering design to control the pressure buildup during CO₂ storage in deep saline aquifer and we propose that the extracted saline formation water can be processed at the industrial level in order to produce commercial salt. We investigated the effects of different aquifer properties to pressure increase. Several design options for the injection operations are investigated: Injection of CO₂ without saline formation water production, Injection of CO₂ with one production well and finally Injection of CO₂ with two production wells (one on the left side and another on right side of the injection well). We showed that an increase in saline formation water production rate leads to pressure buildup decrement, when the production rate was tripled (from 61.42 kg/s to 184.26 kg/s); the maximum pressure decreased about 15 bars. About a half of base case temperature (890C to 450C) increased the maximum pressure to about 35 bars. The pore compressibility which is a key parameter defining the pressure response to CO₂ injection has also been investigated whereby an increase in pore compressibility leads to decrease in pressure buildup. Aquifer with low thickness showed high pressure build up results. Simulations results indicated that the injection arrangement contribute significantly to the pressure development.