Evaluation of the impact of guar gum applied to chemical enhanced oil recovery on produced water treatment using a SDBS-Chitosan flocculant system

ABSTRACT

Chemical enhanced oil recovery (cEOR) is a process that involves the injection of chemicals (like polymers) to improve oil recovery. These processes generate a lot of produced water (PW) that needs to be treated properly for final disposal in the environment. This work has the goal to evaluate the influence of the injection biopolymer guar gum on PW treatment, as well the oil removal efficiency (ORE) of a flocculant system composed by the bioflocculant chitosan and sodium dodecyl benzene sulfonate (SDBS). The flocculation-flotation experiments were planned and carried out based on a design of experiments (central composite rotatable design – CCRD). It was possible to find out that guar gum concentration did not impact oil removal efficiency in a statistically significant way. But chitosan and SDBS concentrations were statistically significant, achieving better ORE when chitosan concentration is between 50 and 100 ppm and SDBS concentration is higher than 200 ppm, achieving a maximum of 86% of ORE at concentrations of 75 ppm and 250 ppm, respectively. The findings of this study can help for better understanding of how nonionic injection biopolymers impact on PW treatment and to propose the use of chitosan as a flocculant along with SDBS to enhance PW treatment.

KEYWORDS:

• Guar gum
• bioflocculant
• chitosan
• SDBS
• oil removal

Acknowledgments

A special thanks to Gustavo de Gusmão Celestino, who did the viscosimetric molar mass analysis.

This research was carried out in association with the ongoing R&D project registered as ANP 20700-1, “Desenvolvimento de biopolímeros para aplicação em recuperação avançada de petróleo” (Universidade Federal do Rio de Janeiro (UFRJ)/Shell Brasil/ANP) – Development of biopolymers for EOR application, sponsored by Shell Brasil under the ANP R&D levy as “Compromisso de Investimentos com Pesquisa e Desenvolvimento”

This study was financed in part by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - Brasil (CAPES) - Finance Code 001.

This work was also supported in part by Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPQ) by Fundação Carlos Chagas Filho de Amparo à Pesquisa do Estado do Rio de Janeiro (FAPERJ).

List of abbreviations

cEOR	=	chemical enhanced oil recovery
PW	=	produced water
ORE	=	oil removal efficiency
SDBS	=	sodium dodecyl benzene sulfonate
HPAM	=	partially hydrolyzed polyacrylamide
O/W	=	oil-in-water
SDS	=	sodium dodecyl sulfate
CCRD	=	composite central rotatable design
1H-NMR	=	proton magnetic resonance spectroscopy
FTIR	=	fourier transform infrared spectroscopy
UFRJ	=	Universidade Federal do Rio de Janeiro
D2O	=	deuterium oxide
DCl	=	deuterium chloride
KBr	=	potassium bromide
TDS	=	total dissolved solids
DD	=	degree of deacetylation
Mv	=	viscometric molar mass
Da	=	Dalton (molar mass unit)
ANOVA	=	analysis of variance
Df	=	degrees of freedom

Disclosure statement

No potential conflict of interest was reported by the author(s).