Polymer flooding represents the most common chemical enhanced oil recovery (CEOR) method used at commercial scale. In this process, the polymeric solutions (generally hydrolyzed polyacrylamide - HPAM) are injected to improve the oil/water mobility ratio (M). However, due to mechanical, chemical, bio, and thermal degradation, polymer viscosity losses can occur, causing a negative impact on oil sweep efficiency. In this case, biopolymers seem to be promising candidates in EOR applications with special structural characteristics, which result in excellent stability in harsh environments with high temperatures, ionic forces, and shear stresses. This paper presents the laboratory evaluation of Scleroglucan (SG) and a commercial sulfonated polyacrylamide (ATBS) in synthetic brine, representative of a Colombian heavy-oil field. The effects of ionic strength, pH, temperature, and shear degradation effects on polymer viscosity were also evaluated. For SG, the results reflect its tolerance to high salinities (0-5%wt), ionic strengths (Na+, K+, Ca2+, and Mg2+), shear rates (0-300,000 s-1), temperatures (30, 50, 80 and 100 °C), and pH variations (3-10). The biopolymer was capable of preserving its viscous properties and stability after of the effect of these variables. Finally, the target viscosity (set as 17 cp) was achieved with a lower concentration (2.7 times) than the ATBS polymer tested.

Colloidal dispersion gels are one of the methodologies implemented, such as chemical recovery processes, in mature wells, their components are mainly polyacrylamide and aluminum citrate, both aqueous unlike other types of gelling, in this there is an intramolecular process, between the polymer chains and the crosslinker, generating a ball of polyacrylamide of nanometric dimensions. The usual gelling processes increase the viscosity of a fluid because of an increase in the molecular weight of the polymer, but in this case, the viscosity of the fluid decreases to the point of being close to that of the solvent, for this reason a monitoring of its gelation kinetics, in a conventional way is not possible, in view of this problem, this research implements techniques of viscoelastic characterization of fluids, to determine the loss and storage modules G′ and G″, as well as the phase angle in the time, in order to learn more about the gelling mechanism, as well as to be able to estimate a reaction speed, from the point of view of viscoelastic variables, the results obtained revealed that despite being gelling, there is a decrease in the storage modulus, to a greater extent than the loss modulus, which implies that the material loses elastic properties, that is, from solid to become a material more viscous or liquid. With this information, an equation was proposed that can be used both in the laboratory and in oil field work. In addition to being extended to fluids with similar behaviors, where the interactions between the polymeric chains and their crosslinker generate a decrease in their elastic properties.