Heterogeneous combination flooding is a new chemical flooding method for further enhancing oil recovery in post-polymer-flooding reservoirs

and its main components of displacing agents include branched preformed particle gel(B-PPG)

polymer and surfactant.According to laboratory experiments

the physicochemical properties of B-PPG and its oil-displacing characteristics are obviously different from that of polymer.The traditional mathematics model and simulators for chemical flooding can not accurately describe the oil displacement mechanism of B-PPG.In order to figure out the mechanism of heterogeneous combination flooding

a concept of particle throughput factor was introduced based on laboratory experiment results.We described the discontinuous migration features of B-PPG particles

modified the mathematical representation of residual resistance coefficient

built a new mathematical model

and performed fast solution algorithm research and software realization.Numerical experiments showed that the mathematical model can satisfactorily describe the oil-displacing mechanism of B-PPG

fit laboratory experiment results

and show good performance in history matching and dynamic tracking in field application.