Key Technologies of Numerical Simulation with CCUS and Application in a Low-Permeability Carbonate Reservoir of the Middle-East

Abstract

In recent years, CO2 flooding is an important technical measure for oil and gas field enterprises to further improve oil and gas recovery and achieve the goal of "dual carbon". It is also one of the concrete application forms of CO 2 flooding and storage (CCUS). Numerical simulation based on CO 2 -EOR plays an indispensable role to study the mechanism of CO 2 flooding and buried percolation, to select technical indicators and to improve EOR/EGR prediction for reservoir engineers. This paper discusses the numerical simulation technologies with CCUS, which include mathematical models and algorithms. A mathematical model of multiphase and multicomponent is formed to describe the flow mechanism of hydrocarbon components-CO 2 -water underground and to simulate the phase diagram of the components. The two-phase P-T flash calculation with SSI (+DEM) and Newton method is adopted to abtain the gas-liquid phase equilibrium parameters.The extreme value judging of the TPD function is used to form the phase stability test and miscibility identification model. A tailor-made multi-stage preconditioner is built up to solve the linear equation of strong-coupled, multiphase, multicomponent reservoir simulation which includes the variable of pressure, saturation, composition, which improves the calculation efficiency by approximately 2-5 times. A numerical simulation of CO2 injection in a carbonate reservoir in the Middle East shows that it's effective for researching the recovery factor and storage rate of CO2 flooding to adopt the above numerical simulation technologies.