Preparation, solution characteristics and displacement performances of a novel acrylamide copolymer for enhanced oil recovery (EOR)

Partially hydrolyzed polyacrylamide (HPAM) is widely used as thickener in enhanced oil recovery (EOR), but the high temperature and salinity of oil reservoirs can reduce the viscosity and lead to polymer precipitation. To improve the performance of HPAM in high‐salinity and high‐temperature environments, the responsive amino‐terminated poly(ethylene oxide‐co‐propylene oxide) (PEOPPO) (EO/PO = 19/03) was grafted onto a HPAM backbone. The copolymers were prepared in water using 1‐ethyl‐3‐[3‐(dimethylamino)‐propyl]carbodiimide hydrochloride/N‐hydroxysuccinimide (EDC/NHS) as activators. Structural characterization was performed by 1H NMR and Fourier transform infrared (FTIR) and the responsive behavior was investigated by UV–Vis and rheology. Spectroscopic analyses confirmed that copolymers were successfully synthesized. UV–Vis showed that copolymers have combined salt and thermoresponsive character. Rheology in saline medium (ionic strength = 3.75 mol.L−1) revealed that, contrary to unmodified HPAM, HPAM‐g‐PEOPPO have thermothickening behavior and also higher viscosity than HPAM at 70 °C, suggesting the utilization of these copolymers as rheological modifiers under harsh conditions of temperature and salinity, such as the ones found in EOR applications. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47453.

Section: Resultsmentioning

confidence: 58%

Section: Resultsmentioning

confidence: 99%

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HPAM‐g‐PEOPPO: Rheological modifiers in aqueous media of high temperature and high ionic strength

Lima

Marques

Villetti

et al. 2019

“…From the practical application effect, the oil recovery efficiency is relatively ideal at last. [1][2][3][4] Therefore, it is of great significance to strengthen the research of polymer flooding oil recovery technology, and there is also plenty of development space. Among various recovery-enhancing polymers, partially hydrolyzed polyacrylamide (HPAM) is the most commonly used.…”

Section: Introductionmentioning

confidence: 99%

“…Shengli and Daqing oil fields also fully used polymer flooding oil recovery technology. From the practical application effect, the oil recovery efficiency is relatively ideal at last 1–4 . Therefore, it is of great significance to strengthen the research of polymer flooding oil recovery technology, and there is also plenty of development space.…”

Section: Introductionmentioning

confidence: 99%

High‐viscoelastic graft modified chitosan hydrophobic association polymer for enhanced oil recovery

Liu

Gou

Zhou

et al. 2020

The conventional partially hydrolyzed polyacrylamide (HPAM) is greatly restricted by its single linear molecular structure in oil reservoirs with severe reservoir conditions such as high temperature and high salt. In this article, the chitosan (CS) grafted imidazoline monomer copolymer (CS-g-AM/AA/NIDA) was prepared from N-maleyl CS (N-MCS), acrylamide (AM), acrylic acid (AA), 1-(2-N-acryloylaminoethyl)-2-oleoyl imidazoline (NIDA) by free radical copolymerization. The structure was determined by means of Fourier transform infrared spectroscopy, 1 H nuclear magnetic resonance spectroscopy, scanning electron microscope, thermal gravimetric analysis, and so forth, which confirmed the successful preparation of the copolymer with good thermal stability. Under the same conditions, compared with HPAM and copolymer CS-g-AM/ AA, CS-g-AM/AA/NIDA greatly increased the viscosity of the aqueous solution and exhibited excellent shear stability (viscosity retention rate 15.62, 4.91, and 11.54% at 510 s −1), temperature resistance (the viscosity retention rate

Thermal stability of polymers based on acrylamide and 2‐acrylamido‐2‐methylpropane sulfonic acid in different temperature and salinity conditions

Vieira

Oliveira

Costa

et al. 2021

Partially hydrolyzed polyacrylamide (PHPA) is the most widely used polymer in enhanced oil recovery (EOR) applications. However, under conditions of high temperature and salinity, the PHPA molecules become hydrolyzed, causing a drastic reduction of the viscosity of the polymer solution due to the presence of negative charges, making the molecules more susceptible to interactions with cations. In this sense, in order to increase the stability of these polymers, an anionic monomer more resistant to cations such as 2‐acrylamido‐2‐methylpropane sulfonic acid (AMPS) has been incorporated into the HPAM molecules. This work evaluated the thermal stability of a copolymer (acrylamide and AMPS ‐ AN125) and a terpolymer (acrylamide, acrylate, and AMPS‐FP5115) in the time course of 360 days. The tests were carried out in typical conditions of Brazilian offshore reservoirs, such as absence of oxygen, high temperature, and high salt concentration. The test method involved measurements of intrinsic viscosity in function of time and determination of the hydrolysis degree of the polymers by elemental analysis. The copolymer AN125 was more stable under the test conditions than the terpolymer FP 5115 due to the presence of a higher concentration of AMPS in the copolymer. The AMPS group was hydrolyzed to AA at a temperature of 100 °C, however, the increase in salt concentration delayed the onset of this degradation. The tests indicated that the presence of a higher AMPS content in the copolymer does not prevent the polymer from undergoing hydrolysis, but delays the polymer precipitation step in the solution.