Study On Mathematical Model And Numerical Simulation Of Heavy Oil Thermal Chemical Flooding

Thermal chemical flooding has been one of the most important methods for enhancing the recovery of heavy oil reservoirs.However,the numerical simulation of the thermo chemical flooding of heavy oil is not sufficient enough to accurately describe the physicochemical reactions and percolation laws between components and phases in the non-isothermal displacement process.In response to this problem,the following research work is carried out using the seepage test method,the theory of non-linear seepage mechanics,numerical method and computer programming.(1)The experimental analysis of the relationship between oil phase relative permeability and temperature,starting pressure gradient and fluidity are conducted.The fitting formulas of relative permeability and temperature,starting pressure gradient and fluidity are obtained respectively.A new heavy oil seepage equation is established,which is considering the influence of temperature.By performing thermal decomposition experiments on different kinds of oil displacement agents,an equation for the relationship between the efficiency of the oil displacement agent and the temperature is established.The novel emulsified viscosity reducer is subjected to water thickening,swelling,crude oil emulsified and core flooding experimental.A new model for the relationship between the concentration of emulsified viscosity reducer and the viscosity of the aqueous phase and the oil phase is proposed.(2)A three-dimensional three-phase multi-component mathematical model for the seepage flow of thermal chemical flooding on heavy oil is established.In this model,the convection,diffusion,chemical reaction and absorption of each component,and the non-Newtonian characteristic,non-linear seepage feature and non-isothermal characteristic of the fluid are all considered.To solve the model,the semi-implicit finite difference method is performed.The simulator is written in Fortran and it implements the addition of procedural functions for starting pressure gradients,high-temperature flooding agents and the novel emulsified viscosity reducer.(3)Based on the ideal geological model,examples about starting pressure gradients,high-temperature flooding agents and the novel emulsified viscosity reducer are simulated with this simulator.The simulation results of this simulator and the popular thermal module prove the reliability of the simulator.The simulation analysis of field examples is performed,based on the geological model of S83 Block in Shengli Oilfield,the principle of equidistant well positions and not changing well locations of the oilfield plan as far as possible.The simulation provides a technical solution for the field implementation of heavy oil thermal chemical flooding.The established mathematical model and numerical simulator of heavy oil thermal chemical flooding in this paper have provided a convenient platform for the functional addition of thermal chemical agents in the future.