Experimental Investigation of the Effect of Polymers on Residual Oil Saturation

Abstract

Summary Polymer flooding is a widely used commercial process with a low cost per barrel of produced oil, and hydrolyzed polyacrylamide (HPAM) polymers are the most widely used type of polymer. The objective of this research was to better understand and predict the behavior of HPAM polymers and their effect on residual oil saturation (ROS), to improve the capability of optimizing field design and performance. The corefloods were performed under typical field conditions of low pressure gradients and low capillary numbers. The polymer floods of the viscous oils recovered much more oil than the waterfloods, with up to 24% lower oil saturation after the polymer flood than after the waterflood. The experimental data are in good agreement with the fractional-flow analysis by use of the assumptions that the true ROSs and endpoint relative permeabilities are the same for both water and polymer. This suggests that, for more-viscous oils, the oil saturation at the end of a waterflood (i.e., at greater than 99% water cut) is better described as “remaining” oil saturation rather than the true “residual” oil saturation. This was true for all the corefloods, regardless of the core permeability and without the need for assuming a permeability-reduction factor in the fractional-flow analysis.

Understanding the flow behaviour of copolymer and associative polymers in porous media using extensional viscosity characterization: Effect of hydrophobic association

“…Recently, the crossover method has been considered to be the most efficient and quick method to determine the longest relaxation time. [8,[49][50][51][52][53][54][55][56] The longest relaxation time determined by the cross-over method was reported to be within the same range of rouse relaxation time. [56] Wilton and Torabi [57] recently used a specialized oscillatory V-E rheometer, based on oscillatory flow, but with the capillary plug for characterizing the EOR polymers.…”

Optimal Design of Alkaline–Surfactant–Polymer Flooding under Low Salinity Environment

“…where t denotes the time recorded at a specific effluent volume and the subscripts 100, 200, and 300 mL represent the effluent volumes. A FR value less than 1.2 is commonly acceptable for nonoccurrence of polymer hydration [20]. Table 4 shows the properties of two cylindrical Berea sandstone cores used in the coreflooding test.…”

Development of novel mathematical models for laboratory studies of hydrolyzed polyacrylamide polymer injectivity in high-permeability conduits

“…The polymer solution will have a high viscosity and thus will overcome several displacement and mobility problems associated with water flooding, mainly viscous fingering (Zhou et al 2019;Seright et al 2018;Seright 2017). Different types of polymers have been developed and used to improve oil recovery and mobility control; however, HPAM polymer still remains the most widely used polymer for chemical EOR applications mainly due to its cost, availability, and ease of handling (Seright 2017;Koh et al 2018;Fletcher et al 1992;Buell et al 1990;Gerlach et al 2019).…”