An experimental study comparing the stability of colloidal dispersion gels with normal polymeric solutions for enhanced‐oil‐recovery purposes

Abstract

Waterflooding in oil reservoirs is associated with several drawbacks. Recently, colloidal dispersion gels (CDG) have been proposed as a new method for conformance control to address these drawbacks. CDGs are prepared by mixing crosslinkers and polymers in very low concentrations as a result of intramolecular crosslinking. In this research, a comprehensive study was conducted on the stability of sulfonated polyacrylamide (SPAM) solutions and CDGs prepared using the same SPAM in harsh conditions. The effects of high temperature, shear rate, salts, and high mechanical degrading on the viscosity of both polymeric solution types were studied using a rheometer. The results showed that, in similar conditions, CDGs are less susceptible to salts than are normal SPAM solutions. Moreover, both solutions have nearly the same sensitivity to temperature. The effect of extremely high shear rates was also studied, and the results suggested that, in similar conditions, CDG is less susceptible to high shear rates than normal SPAM solutions. Being treated at 2500 1/s for 2 hours, the CDG solution lost almost 0% of its original viscosity, while the SPAM solution lost 0.97% of its original viscosity. Given that CDG is more stable in harsh reservoir conditions, it may be a suitable substitute to the highly sensitive polymeric solutions for improving the volumetric sweep efficiency of waterfloods.

Effect of silicon dioxide nanoparticles on the rheology properties of fresh and mechanically degraded hydrolyzed polyacrylamide polymer solutions

“…11 This viscoelastic effect has been associated with a reduction of residual oil saturation below the levels attained with viscous liquid flooding, thereby increasing oil recovery. [12][13][14][15][16] The positive effects of deformation thickening are hampered by mechanical degradation, which occurs as polymer molecules experience high-deformation rates while traversing pumps, flow lines, constrictions, valves, and reservoirs. 10 The deformation rate experienced as the polymer solution flows through the reservoir rock is in the range of 50,000 to 100,000 s À1 in regions close to the injection wells.…”

“…This behavior can be associated with a change in polymer conformation, resulting in highly extended polymer configurations and large extensional stresses 11 . This viscoelastic effect has been associated with a reduction of residual oil saturation below the levels attained with viscous liquid flooding, thereby increasing oil recovery 12–16 …”

Preparation of Preformed Submicron Crosslinked Polymer Coils for Conformance Control in Low-Permeability Reservoirs

“…These agents can be classified into two broad categories: in situ prepared agents and preformed agents. In situ prepared agents include colloidal dispersion gels (CDGs) [ 5 , 6 ], linked polymer solutions (LPSs) [ 7 , 8 ], etc. Preformed agents include dispersed particle gels (DPGs) [ 9 , 10 , 11 ], preformed particle gels (PPGs) [ 12 , 13 ], polymer microspheres (PMs) [ 14 , 15 , 16 ], etc.…”