Experimental and Monte Carlo simulation of palmitate-guar gum derivative as a novel flooding agent in the underground reservoir

Abstract

Nowadays, biopolymers acquire incremental attention on industrial scale owing to their distinct properties. Guar gum is a hydrophilic, biodegradable polysaccharide widely implemented in several industries. In this study, native guar gum (GG) and palmitate-guar gum (PGG) were evaluated as potential candidates for enhanced oil recovery (EOR). Spectroscopic characterization of GG and PGG conducted through FT-IR and 1H NMR spectra. Thermal behavior screened through TGA, DSC and DTA analysis. Moreover, the surface morphology and grafting process investigated through Atomic force microscope (AFM) images. Rheological behavior modeled as a function of shear stress/shear rate and viscosity/shear rate profiles. Both biopolymers display shear-thinning performance and well fitted with Allometric1model, while scanning of shear stress is well fitted by the Hershel-Bulkley model. The rheological assessment confirms that GG and PGG solutions exhibit non-Newtonian performance and reasonable salt resistance. In addition, the elastic and dynamic properties indicate that GG and PGG systems are elastic gels since elastic modulus (G′) prevail viscous modulus (G″). On the other hand, the Monte Carlo simulation conducted to investigate the molecular mechanisms involved in the wettability alteration through adsorption of biopolymer chains on SiO2-quartz crystal. The obtained simulation outputs reveal that PGG film is more stable than GG film and displays a higher surface coverage, and more negatively electrostatic energies with SiO2-quartz crystal rather than GG. Moreover, contact angle and wettability alteration assessed mathematically as a function of capillary pressure and interfacial tension of water/oil phases. Flooding tests conducted on sandstone core at nearby reservoir conditions and cumulative oil recovery was reported relevant to injected pore volumes. Based on the core flooding data, the reported GG and PGG biopolymers can be considered as a well-optimized EOR- and wettability modifying candidates in the saline reservoirs.