Polymer Flooding in Heterogeneous Heavy Oil Reservoirs: Experimental and Simulation Studies.

Xiankang Xin,Keliu Wu,Gaoming Yu,Zhangxin Chen,Xiaohu Dong

doi:10.3390/polym13162636

Xiankang Xin, Keliu Wu + Show 3 more

Open Access

https://doi.org/10.3390/polym13162636

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Abstract

Polymer flooding (PF) in heterogeneous heavy oil reservoirs is not only closely related to polymer degradation, but also to non-Newtonian flow. In this paper, both experimental and simulation methods are combined to investigate this type of flooding. Through experiments, the degradation of polymer, rheological properties of fluids, and flow of fluids in porous media were determined. Based on the experimental results, a novel mathematical model was established, and a new PF simulator was designed, validated, and further applied to study the effects of polymer degradation, polymer solution shear thinning, and non-Newtonian flow on PF in heterogeneous heavy oil reservoirs. These experimental results demonstrated that the polymer first-order static degradation rate constant was lower than the polymer first-order dynamic degradation rate constant; the polymer solution and heavy oil were non-Newtonian fluids, with shear thinning and Bingham fluid properties, respectively; and the heavy oil threshold pressure gradient (TPG) in low-permeability porous media was higher than that in high-permeability porous media. All comparison results showed that the designed simulator was highly accurate and reliable, and could well describe both polymer degradation and non-Newtonian flow, with special emphasis on the distinction between polymer static and dynamic degradation and heavy oil TPG. Furthermore, the simulation results verified that polymer degradation, polymer solution shear thinning, and heavy oil TPG all had negative effects on the efficiency of PF in heterogeneous heavy oil reservoirs.

Highlights

As a source of global economic development, energy has become increasingly prominent as the process of economic globalization continues to accelerate [1]
The experimental results demonstrated that the polymer first-order dynamic degradation rate constant was higher than the polymer firstorder static degradation rate constant; the polymer solution had a typical shear thinning, and the heavy oil exhibited Bingham fluid characteristics; the flow of heavy oil in porous media was needed to overcome threshold pressure gradient (TPG)
A novel and beneficial polymer flooding (PF) simulator was designed based on a new mathematical model, which provided a good description of polymer degradation and non-Newtonian flow, especially for distinguishing between the static and dynamic degradation of polymers as well as describing TPG

Summary

Introduction

As a source of global economic development, energy has become increasingly prominent as the process of economic globalization continues to accelerate [1]. With the continuous exploitation of crude oil resources in recent decades, the production of conventional crude oil resources has decreased, and it is difficult to meet the global crude oil demand [3]. Among many enhanced oil recovery (EOR) methods, polymer flooding (PF) has become a commonly used method due to its wide range of field applications. It has advantages in supplementing energy and promoting sweep efficiency in heterogeneous heavy oil reservoirs [4]. The study of PF in heterogeneous heavy oil reservoirs is necessary to increase the efficiency of heavy oil development and meet the global crude oil demand

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Results

Conclusion