Polymer flooding consists of injecting polymer-augmented water into the reservoir to control the water-oil mobility ratio, resulting in an increase in the volumetric sweep efficiency compared to water flooding. Synthetic polymers (polyacrylamides) and biopolymers (scleroglucan, xanthan gum, schizophyllan) are the two families of polymers usually evaluated for enhanced oil recovery (EOR). Scleroglucan (SCG) is resistant to electrolytes, hydrolysis, pH (3-10) and temperature (30-100°C) and has remarkable rheological properties, but it is quite susceptible to microbiological degradation. The primary objective of this study was to evaluate the biodegradation of SCG in the injection and production processes and its aquatic toxicity. The anaerobic biodegradation of the SCG solutions was determined through the viscosity changes of the solutions, while the aerobic biodegradation was calculated with the changes in the SCG concentration.  It was observed that the viscosity reduction of the SCG solution was 30% and the SCG concentration decreased from 100 ppm to 52 ppm because bacteria can metabolize the biopolymer. Daphnia Pulex, Scenedesmus Acutus and Oreochromis sp. were the organisms used in the ecotoxicological assays of the SCG solutions. The acute ecotoxicological bioassays showed that there was no evidence of acute deleterious effects of SCG on any of the three organisms. From the chronic ecotoxicological bioassays, it was concluded that there was no effect of SCG on the mortality of Daphnia Pulex, regardless of the tested SCG concentration.

Biocorrosion is a phenomenon that strongly affects the integrity of the materials used in the oil and gas industry. Different types of biocides are currently used to control bacteria in industrial water; however, they have disadvantages such as microbial resistance to these chemical compounds and possible impact on biodiversity due to eventual contamination of natural water. There are several alternatives for the elimination or control of bacteria, among which one is the use of type C ultraviolet (UV-C) radiation. Nevertheless, the use of these micro-organism removal systems could be affected by water quality and its efficiency can be improved by using LED diodes of lower energy consumption and greater versatility in exposure to high temperatures. This work was aimed to evaluate the use of such radiation as a strategy for the control and/or elimination of sulfate reducing bacteria (SRB), and acid producing bacteria (APB) present in both corrosion and souring processes.  For this purpose, injection water from oil and gas industry and a dynamic system which flow variation enabled the evaluation of different water exposure times to UV-C light (1-20 minutes) were used. Efficiencies ranging between 99-100% were achieved in the elimination of SRB and APB from produced water measured by two different techniques, selective culture media for these microbial populations, and qPCR detecting a specific gene from the SRB population.