Bulk rheology characterization of biopolymer solutions and discussions of their potential for enhanced oil recovery applications

Abstract

Enhanced oil recovery (EOR) techniques are essential to improve oil production, and polymer flooding has become one of the promising technologies for the Brazilian Pre-Salt scenario. Biopolymers offer a range of advantages considering the Pre-Salt conditions compared to synthetic polymers, such as resistance to high salinity, high temperature, and mechanical degradation. In that sense, bulk rheology is the first step in a workflow for performance analysis.
 This paper presents a rheological analysis of four biopolymers (Schizophyllan, Scleroglucan, Guar Gum, and Xanthan Gum) in concentrations from 10 to 2,300 ppm, generally suitable for EOR applications, in temperature levels of 25, 40, 50, 60 and 70°C and two brines of 30,100 ppm and 69,100 ppm total dissolved solids, which aim to model seawater and the mixture between injected seawater and reservoir water typical in Pre-Salt conditions. The pseudoplastic behavior, the overlap concentration, and the activation energy were determined for each polymer solution.
 The structural differences in the polymers resulted in different rheological behaviors. Schizophyllan is the most promising, as its viscosifying power is higher than synthetic polymers comparable to Xanthan Gum. Its resistance at high temperatures is higher than that of synthetic polymers. Scleroglucan behaved similarly to Xanthan Gum, with the added advantage of being nonionic. Guar Gum had the lowest viscosities, highest overlap concentrations, and most pronounced viscosity decay among the tested polymers.
 To the author’s knowledge, rheological studies of the biopolymers presented here, considering the viscosities and the overlap concentration and activation energy, in the Pre-salt conditions, are not available in the literature and this will benefit future works that depend on this information

Experimental Investigation of the Viscosity and Stability of Scleroglucan-Based Nanofluids for Enhanced Oil Recovery

“…However, synthetic polymers are affected by reservoir temperature, formation water salinity, and hardness [ 8 ]. Polysaccharides such as xanthan gum (XG) [ 9 ], carboxymethylcellulose (CMC) [ 10 ], schizophyllan (SPG) [ 11 ], and scleroglucan (SG) [ 12 ] have emerged as an alternative to HPAM due to their remarkable rheological properties and resistance to hydrolysis, pH, electrolytes, mechanical shearing, and temperature [ 13 , 14 ].…”

Evaluation of Viscosity Changes and Rheological Properties of Diutan Gum, Xanthan Gum, and Scleroglucan in Extreme Reservoirs

“…This technology has received attention owing to its eco-friendly attributes, superior applicability, and cost-effectiveness [19][20][21][22][23]. Zhou Hongtao [13] explored the feasibility of diutan gum, welan gum, and xanthan gum as new polymers for oil repulsion; Zhang Xifeng [24] investigated the static and dynamic rheological properties of a welan gum aqueous solution at a formation temperature of 40 • C and the factors affecting them; Karl-Jan [25] investigated the rheology of schizophyllan, scleroglucan, guar gum, and xanthan gum in brines at concentrations ranging from 10 to 2300 mg/L, temperature levels ranging from 25 to 70 • C, and total dissolved solids concentrations of 30,100 mg/L and 69,100 mg/L; and Lai Nanjun [26] investigated the rheological properties and the recovery-enhancing ability of diutan gum, xanthan gum, and konjac gum at a temperature of 130 • C and a mineralization level of 223.07 mg/L. However, less research has been carried out on the viscosity enhancement, rheological properties, and long-term stability of the three biopolymers, namely, diutan gum, xanthan gum, and scleroglucan, under extreme reservoir conditions.…”