Xanthan gum produced by Xanthomonas campestris using produced water and crude glycerin as an environmentally friendlier agent to enhance oil recovery

• Published in: Fuel (Guildford) Vol. 310; p. 122421
• Main Authors: Ramos de Souza, Elias, Rodrigues, Pamela Dias, Sampaio, Igor C.F., Bacic, Edgard, Crugeira, Pedro J.L., Vasconcelos, Anaís Couto, dos Santos Silva, Maíra, dos Santos, Jacson N., Quintella, Cristina M., Pinheiro, Antonio L.B., Almeida, Paulo Fernando de
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 15.02.2022; Elsevier BV
• Subjects: Aerobic conditions; Chemical properties; Enhanced oil recovery; Flooding; Gums; Industrial wastes; Injection; Metabolites; Microbial Enhanced Oil Recovery; Microorganisms; Oil; Oil wastes; Physicochemical properties; Polymers; Produced Water Xanthan; Pseudoplasticity; Rheological properties; Secondary oil recovery; Sodium chloride; Thermoviscosifying polymer; Viscosity; Viscosity ratio; Water wells; X ray spectra; Xanthan; Xanthan gum; Xanthomonas campestris; Microbial Enhanced Oil Recovery; Produced Water Xanthan; Thermoviscosifying polymer
• ISSN: 0016-2361; 1873-7153
• DOI: 10.1016/j.fuel.2021.122421

The use of Produced Water Xanthan (PWX) as a chemical flooding metabolite for Enhanced Oil Recovery (EOR) is described. PWX was synthesized by Xanthomonas campestris in a culture medium containing produced water from oil wells and crude glycerin. PWX key physico-chemical properties for application as an EOR agent are investigated and comparisons between PWX and SigmaTM Xanthan Gum (SXG) are given. X-ray spectra indicate the presence of Zn and Fe atoms in PWX. Rheological analyses show that both polymers exhibit non-Newtonian, pseudoplastic behaviour in solution. While SXG shows a reverse linear relationship between apparent viscosity and temperature, PWX may behave as a thermoviscosifying polymer (TVP). However, viscosities of PWX at 0.7% w/w and of SXG at 0.5% w/w are comparable above 60 °C. The critical polymer concentrations at 65 °C for SXG and PWX are 0.47% and 0.59%, respectively. Polymeric solutions of either xanthan gums were then tested as EOR fluids in carbonate plugs by considering the time of polymer injection: early injection is taken as a secondary oil recovery and late injection as a tertiary recovery. Increase in oil recoveries were similar for PWX and SGX when the injected solutions had the same viscosity. Because late injection requires the injection of a non-polymeric solution before flooding polymer, early injection required much less water to reach the same recovery factor. Also, the oil recovery increased when salt was added to a SXG or PWX solution, indicating that factors other than the water/oil viscosity ratio play a role in oil recovery. Having nearly the same viscosity, polymeric solutions of 0.7% w/w PWX and 0.5% w/w SXG in water, both with NaCl at 0.6% w/w, were tested as EOR fluids in tertiary recovery, under the same experimental conditions, leading to increases in oil recovery of 11% for SXG and 19% for PWX. Because Xanthomonas campestris only yields significant amounts of PWX in low salinity and aerobic conditions, PWX may be effective as an ex-situ Microbial Enhanced Oil Recovery metabolite. Once PWX is obtained from industrial wastes, it is environmentally friendlier than commercial xanthan gums. •Produced Water Xanthan (PWX) is obtained from industrial wastes.•PWX presents Fe and Zn metallic complexes in addition to pyruvate and acetyl.•PWX exhibits thermoviscosifying behaviour in the range 55 to 70 °C.•PWX presents greater stability to salinity than SigmaTM Xanthan Gum.•PWX increased the oil recovery up to 19% in carbonate plugs tests.