Shear Resistance Properties of Modified Nano-SiO2/AA/AM Copolymer Oil Displacement Agent

Nanjun Lai,Xin Guo,Qian Xu,Ning Zhou

doi:10.3390/en9121037

Nanjun Lai, Xin Guo + Show 2 more

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https://doi.org/10.3390/en9121037

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Journal: Energies	Publication Date: Dec 9, 2016
Citations: 26	License type: CC BY 4.0

Affiliation: Southwest Petroleum University, University of Regina

Abstract

To address the problem regarding poor shear resistance of commonly employed polymers for oil displacement, modified nano-SiO2/AA/AM copolymer (HPMNS) oil displacement agents were synthesized using acrylic acid (AA), acrylamide (AM), and modified nano-SiO2 of different modification degrees as raw materials. HPMNS was characterized by means of infrared spectroscopy (IR), nuclear magnetic resonance (1H-NMR, 13C-NMR), dynamic/static light scattering, and scanning electron microscope. A comparative study of the shear resistance properties for partially hydrolyzed polyacrylamide (HPAM) and HPMNS was conducted. Compared to HPAM, the introduced hyperbranched structure endowed HPMNS with good shear resistance, which was quantified from the viscosity retention ratio of the polymer solutions. From the perspective of rheological property, HPMNS also showed great shear stability after shearing by a Mixing Speed Governor and porous media shear model. Furthermore, with a higher degree of modification, HPMNS-2 had better shear stability in terms of viscosity and rheological property than HPMNS-1. The phenomena were due to its lower hydrodynamic radius, weight-average molecular weight, and better flexibility of its molecular chains. In addition, upon the indoor displacement test, the resistance factor and residual resistance factor values of HPMNS-2 were higher than those of HPAM. This behavior is beneficial for increasing oil recovery.

Highlights

Polymer flooding is an important technology to extend oilfield life and increase oilfield production [1,2,3,4,5,6,7,8]
Employing polymer flooding for enhancement of oil recovery has major advantages, and considerable drawbacks [10]. One such drawback is the lack of stability in terms of viscous and viscoelastic properties of hydrolyzed polyacrylamide (HPAM) caused by shearing actions of the stirrer, pipeline valve, injection pump, shot hole, and porous media during preparation and injection of polymer solution
A certain amount of modified nano-SiO2, acrylic acid (AA), and AM were placed in a 100 mL three-necked flask

Summary

Introduction

Polymer flooding is an important technology to extend oilfield life and increase oilfield production [1,2,3,4,5,6,7,8]. As the most commonly used polymer in field applications, a small quantity of partially hydrolyzed polyacrylamide (HPAM) can increase the viscosity of water by 2 or more orders of magnitude in the absence of added electrolytes because of the extremely high molecular weight and the repulsion between the negative charges along the polymer chain [9]. Employing polymer flooding for enhancement of oil recovery has major advantages, and considerable drawbacks [10]. One such drawback is the lack of stability in terms of viscous and viscoelastic properties of HPAM caused by shearing actions of the stirrer, pipeline valve, injection pump, shot hole, and porous media during preparation and injection of polymer solution. One of the most common and obvious effects of this instability is significantly reduced viscosity of HPAM solutions when its linear architecture undergoes such scission, seriously reducing its ability to enhance oil recovery [8,10,11,12,13,14,15,16].

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