TY - JOUR
T1 - Towards enhanced oil recovery
T2 - Effects of ionic valency and pH on the adsorption of hydrolyzed polyacrylamide at model surfaces using QCM-D
AU - Mohan, Amrutha
AU - Rao, Ashit
AU - Vancso, Julius
AU - Mugele, Frieder
N1 - Funding Information:
The work of Mohan, A. forms part of the research program of Dutch Polymer Institute (DPI project number: 807, P.O. Box 902, 5600 AX Eindhoven, the Netherlands). We acknowledge SNF.SA for synthesizing the polymer for the experiment and support. We also thank Shell for sharing knowledge in the field of EOR. We also extend our gratitude to (ING.) Nathalie Schilderink for experimental support.
Funding Information:
The work of Mohan, A. forms part of the research program of Dutch Polymer Institute (DPI project number: 807, P.O. Box 902, 5600 AX Eindhoven, the Netherlands). We acknowledge SNF.SA for synthesizing the polymer for the experiment and support. We also thank Shell for sharing knowledge in the field of EOR. We also extend our gratitude to (ING.) Nathalie Schilderink for experimental support.
Publisher Copyright:
© 2021
PY - 2021/9/15
Y1 - 2021/9/15
N2 - Adding polymers to the injection water in water-flooding oil recovery increases the viscosity and thereby enhances recovery factor. However, the beneficial effects are often counteracted by adsorption of polymer to the ambient mineral surface. In here, we used Quartz Crystal Microbalance with Dissipation (QCM-D) measurements to study the adsorption of the frequently used hydrolyzed polyacrylamide (HPAM), a weak polyelectrolyte, to silica and alumina model surfaces representing sandstone reservoirs. At pH 6 and 8 and concentrations from 1 mM to 100 mM of NaCl and CaCl2, we find that negatively charged HPAM molecules generally adsorb more strongly to positively charged alumina surfaces. For silica surfaces, the presence of Ca2+ ions, which form strong complexes with the carboxyl groups on the polymer, as evidenced by titration measurements, strongly enhances HPAM adsorption. This effect is attributed to the formation of Ca2+-mediated ion bridges with the substrate. Kinetic measurements suggest a two-step adsorption process consisting of a primary polymer adsorption onto the surface followed – in most cases – by a slower secondary process, which involves rearrangements of previously adsorbed polymer molecules, including polymer-on-polymer adsorption.
AB - Adding polymers to the injection water in water-flooding oil recovery increases the viscosity and thereby enhances recovery factor. However, the beneficial effects are often counteracted by adsorption of polymer to the ambient mineral surface. In here, we used Quartz Crystal Microbalance with Dissipation (QCM-D) measurements to study the adsorption of the frequently used hydrolyzed polyacrylamide (HPAM), a weak polyelectrolyte, to silica and alumina model surfaces representing sandstone reservoirs. At pH 6 and 8 and concentrations from 1 mM to 100 mM of NaCl and CaCl2, we find that negatively charged HPAM molecules generally adsorb more strongly to positively charged alumina surfaces. For silica surfaces, the presence of Ca2+ ions, which form strong complexes with the carboxyl groups on the polymer, as evidenced by titration measurements, strongly enhances HPAM adsorption. This effect is attributed to the formation of Ca2+-mediated ion bridges with the substrate. Kinetic measurements suggest a two-step adsorption process consisting of a primary polymer adsorption onto the surface followed – in most cases – by a slower secondary process, which involves rearrangements of previously adsorbed polymer molecules, including polymer-on-polymer adsorption.
KW - 2022 OA procedure
KW - Enhanced oil recovery
KW - Hydrolyzed polyacrylamide
KW - Polyelectrolyte
KW - Polymer adsorption
KW - QCM-D
KW - UT-Hybrid-D
KW - Calcium bridging
UR - http://www.scopus.com/inward/record.url?scp=85107113245&partnerID=8YFLogxK
U2 - 10.1016/j.apsusc.2021.149995
DO - 10.1016/j.apsusc.2021.149995
M3 - Article
AN - SCOPUS:85107113245
SN - 0169-4332
VL - 560
JO - Applied surface science
JF - Applied surface science
M1 - 149995
ER -