Rock physics study of the Nisku aquifer from results of reservoir simulation

Davood Nowroozi, Donald C. Lawton

This paper is part of the comprehensive reservoir study in the Wabamun Area for CO2 sequestration in the Nisku aquifer. Rock physics is the link between reservoir simulation and 4D seismic. The paper engages rock physics to calculate physical parameters for the solid part, fluid and jointly in the reservoir due to CO2 injection to the Nisku aquifer in the project. The study is based on a new well drilled in the area. The density and wave velocities in the fluids are a function of the pressure and temperature. For CO2 physical properties, the equations of state and for brine, paper were bases for the calculations. In the reservoir, the fluid is a mix of CO2 and brine with various fractions of them, and Reuss average is used to calculate the mix fluid properties. Finally some equations are introduced for the fluid properties for the specific reservoir condition.

Gassmann's equations were used for estimating the saturated bulk modulus and the velocity in the each cell of the reservoir is available, so each cell has own physical model as a function of the pressure and the injection time as this process is isothermal.