Designing Injection Water for Enhancing Oil Recovery from Kaolinite Laden Hydrocarbon Reservoirs: A Spectroscopic Approach for Understanding Molecular Level Interaction during Saline Water Flooding

Abstract

Numerous experiments were performed to understand the mechanism(s) behind incremental oil recovery from hydrocarbon reservoirs during low saline water flooding (LSWF). It is believed that the roles of clay minerals present in the hydrocarbon reservoir rocks and the salt concentration in the injected water have a significant effect on the oil recovery during LSWF. Yet, the exact interaction mechanism(s) is still doubtful for designing injection fluids for enhancing oil recovery from subsurface reservoirs. For understanding the interaction between reservoir components explicitly, kaolinite and crude oil, and the interaction between reservoir components and injection saline water, three dead crude oil samples collected from different reservoirs of Cambay basin, India, and two kaolinite powder samples were used in this study. The kaolinites are different on the basis of their exchangeable cations, Fe 3+ substitution in octahedral sites, and cation exchange capacity (CEC) values. The three crude oils show differences regarding asphaltene content and the abundance of polycyclic aromatic hydrocarbon in asphatenes. The interaction between reservoir components, particularly, kaolinite and crude oil, was demonstrated by keeping both the kaolinite and crude oil mixtures for two months. Detailed analysis of X-ray diffraction patterns, Fourier transform infrared (FTIR) spectra, and CEC values indicated that the polar oil components are adsorbed onto the interlayer surfaces of kaolinite, making it oil wet, and the interaction depends highly upon the composition of kaolinite and crude oil. The oil removal capacity of three brine concentrations of 500 (low saline), 3000 (intermediate saline), and 8000 ppm (high saline) of NaCl, CaCl 2, and MgCl 2 from oil adsorbed kaolinites was investigated using UV−visible and fluorescence spectroscopy techniques. The present study demonstrated that low saline water (500 ppm) rich in Na + ion is more capable of desorbing the maximum amount of 4−6 ring size polycyclic aromatic hydrocarbon (PAH) components from kaolinite interlayer surfaces with respect to Ca 2+ and Mg 2+ ions. The composition of polar oil components, particularly, asphaltenes enriched with 4−6 ring PAH, greatly influences the recovery of oil from a mixed wet to oil wet kaolinite laden hydrocarbon reservoir during saline water flooding. Thus, apart from the concentration level of the saline water, the type of cation present in the saline water plays the major role during LSWF. The kaolinite composition, its crystallinity, and ring size of PAH in asphaltenes present inside a hydrocarbon reservoir also influence the enhanced oil recovery (EOR). These molecular level insights are valuable for designing effective injection fluids for enhancing oil recovery during LSWF in kaolinite laden hydrocarbon reservoirs.

Experimental Investigation on the Pore-Scale Mechanism of Improved Sweep Efficiency by Low-Salinity Water Flooding Using a Reservoir-on-a-Chip

“…Both the cations in the brine and kaolinite composition can influence the oil recovery. 25 Furthermore, the type of cations present on the surface of montmorillonite and the size of polycyclic aromatic hydrocarbon in asphaltenes affect the interaction phenomenon. This provides molecular-level insights into montmorillonite and brine, which are necessary to design optimal injection fluids for the EOR.…”

“…Sanyal reported the effect of clay mineral on oil recovery during low-salinity water flooding. Both the cations in the brine and kaolinite composition can influence the oil recovery . Furthermore, the type of cations present on the surface of montmorillonite and the size of polycyclic aromatic hydrocarbon in asphaltenes affect the interaction phenomenon.…”

Interaction study of clay-bearing amphibolite–crude oil–saline water: Molecular level implications for enhanced oil recovery during low saline water flooding

“…Low saline water flooding (LSWF) is one of such techniques which has been extensively employed in the field of enhanced oil recovery (EOR). It has been proved that the presence of clay minerals is one of the key factors for 1 successful implementation of the LSWF (Morrow and Buckley 2011;Austad 2013;Sanyal et al 2017). Clay minerals are sheet silicate or phyllosilicate structures containing mostly aluminium, silicon and small amounts of other elements such as iron, sodium, magnesium, calcium, potassium, etc.…”

“…Petroleum crudes in the hydrocarbon reservoirs comprises four major components: saturates (S), aromatics (A), resins (R) and asphaltenes (As) (Shi et al 2010). Resins and asphaltenes are polar hydrocarbon components having high affinity towards the clay mineral surfaces and interlayer surfaces (Cosultchi et al 2005;Underwood et al 2015;Sanyal et al 2017). The polar components are adsorbed onto the surface of clay minerals predominantly by van der Waals energy with the smaller contribution of electrostatic energy and H-bonding energy (Murgich and Rodriguez 1998;Underwood et al 2015).…”

“…have been used over the last few decades for the chemical characterisation of crude oil components (Ryder 2005;Zhao et al 2006;Yoon et al 2009;Pantoja et al 2011;Meléndez et al 2012). However, the use of spectroscopic techniques particularly to understand the molecular level interaction among rock powder, crude oil and injection saline water and thereby designing the effective injection saline water for enhancing the oil recovery is very limited in the literature (Fogden 2012;Katika et al 2016;Sanyal et al 2017). In the present work, an attempt has been made to understand the molecular level interaction among clay-bearing amphibolite powder, crude oil and saline water for designing the injection water for effective LSWF.…”