In this study, pressure response at A monitoring well in early stage of CO2 geological storage were predicted against pressure build-up at CO2 injector after starting CO2 injection into a deep saline aquifer to design the monitoring well distance from the injector and resolution or sensitivity of a pressure transmitter installed in the monitoring well. The numerical simulations on pressure distributions and expanding CO2 plume front were carried out using a reservoir simulator, CMG-STARS, for the aquifer (10 km in radius, 50m in height) with open boundary under 1,000 m from the ground or seabed level. The ratio of pressure response at the monitoring well against the pressure build-up at the injector have been presented for various monitoring locations (500 to 5,000 m from a injector) and homogeneous and heterogeneous models of horizontal permeability distribution in the aquifer (Base Model and Model 1, 2 & 3) and CO2 injection patters during 100 days (Scheme 1, 2 & 3). It has been presented from the numerical simulation results that the monitoring well radial distance from the injector is recommended to be 2,000 to 4,000 m or less than 1000 m when the resolution or sensitivity of the pressure transmitter is 1kPa or 10kPa, respectively.
