Paper Number
ET14 

Session
Advanced Experimental Techniques/Methods in Rheology

Title
High-pressure linear viscoelasticity measurements of polymer solutions and gels

Presentation Date and Time
October 17, 2018 (Wednesday) 9:50

Track / Room
Track 5 / San Felipe Room

Authors (Click on name to view author profile)

  1. Dennis, Kimberly A. (University of Delaware)
  2. Gao, Yan (Schlumberger)
  3. Phatak, Alhad (Schlumberger)
  4. Furst, Eric M. (University of Delaware, Dept. of Chemical and Biomolecular Engineering)

Author and Affiliation Lines (in printed abstract book)
Kimberly A. Dennis1, Yan Gao2, Alhad Phatak2, and Eric M. Furst1
1University of Delaware, Newark, DE 19716; 2Schlumberger, Sugar Land, TX

Speaker / Presenter 
Dennis, Kimberly A.

Text of Abstract
Enhanced oil recovery (EOR) fluids are polymer solutions and gels that are designed to transport and suspend solids, reduce friction, and prevent fluid loss. EOR fluid performance depends on its viscosity and elastic modulus. To address the need to characterize the viscoelasticity of EOR fluids under operating conditions, we developed a passive microrheology experiment capable of generating pressures up to 200 MPa. The apparatus incorporates a sealed steel alloy sample chamber with dual sapphire windows into a diffusing-wave spectroscopy (light-scattering) experiment. The measured light intensity correlation arising from the Brownian motion of polystyrene probe particles dispersed in the sample is interpreted using the Generalized Stokes-Einstein Relation (GSER) to determine the material creep compliance. We validate this high-pressure microrheology instrument by measuring the increase in viscosity of 1-propanol aqueous solutions and extend the measurement to EOR fluids containing poly(vinyl) alcohol polymer and borate as a physical crosslinker. Sample loading methods were designed to prevent the introduction of bubbles, which inhibits pressurization by increasing the sample compressibility. However, these methods were limited to low modulli samples that could be easily loaded with a syringe and needle. New methods for increasing the operating regime to nonergodic gel samples as well as higher temperatures have been developed. We investigate the effect of pressure on the crosslink density and rheological properties at frequencies up to 1 MHz and pressures to 200 MPa.