Investigation on the influence of sulfonic substitution in polyacrylamides for minimizing drag in turbulent flow of slickwater fluids

• Published in: Journal of applied polymer science Vol. 141; no. 3
• Main Authors: Korlepara, Navneeth Kumar, Patel, Nikhil, Dilley, Christopher, Deysarkar, Asoke Kumar, Kulkarni, Sandeep D.
• Format: Journal Article
• Language: English
• Published: Hoboken, USA John Wiley & Sons, Inc 15.01.2024; Wiley Subscription Services, Inc
• Subjects: controlled‐MW; Drag reduction; Fluid flow; Hydraulic fracturing; NMR spectroscopy; Parameters; Polyacrylamide; Polymers; Salinity; salt‐tolerance; SPAM; Substitutes; sulfonation; Sulfonic acid; Turbulent flow
• ISSN: 0021-8995; 1097-4628
• DOI: 10.1002/app.54806

The use of slickwater fluids for fracking is key for accessing unconventional shale/tight‐sand reservoirs. To mitigate the frictional losses observed during the injection, drag reducers like sulfonated polyacrylamides (SPAMs) are added to the slickwater fluids. The current study presents a unique controlled investigation that examines the impact of sulfonic group substitution, ranging from 5 to 25 wt%, in SPAMs. The molecular weight of the polymers is kept constant at ~7.5–7.8 million Daltons. The investigation is two‐pronged: first part is comprised of drag reduction (%DR) performance of the polymers in fluids of varying salinities on a laboratory flow‐loop. The results obtained indicated the inter‐dependence of fluid salinity and sulfonic substitution on the polymer performance; for example, %DR deterioration of SPAM with 5 wt% substitution was 24.7%; to the contrary, the deterioration was only 15.6% for SPAM with 25 wt% substitution with rise in fluid salinity from 150 ppm to 110 k ppm. The second part of study included in development of a physics‐based model where the polymer relaxation response (Weissenberg number) was improvised to accommodate the impact of governing parameters and then, successfully correlated with the %DR performance using phenomenological equations for the studied range of parameters. Drag reduction in slickwater fluids; An inter‐play between fluid salinity and polymer sulfonic‐substitution.