Nanotechnology-Assisted EOR Techniques: New Solutions to Old Challenges

Abstract

Enhanced Oil Recovery techniques are gaining more attention worldwide as the proved oil reserves are declining and the oil price is hiking. Although many giant oil reservoirs in the world were already screened for EOR processes, the main challenges such as low sweep efficiency, costly techniques, possible formation damages, transportation of huge amounts of EOR agents to the fields especially for offshore cases, analyzing micro-scale multi-phase flow in the rock to the large scale tests and the lack of analyzing tools in traditional experimental works, hinder the proposed EOR processes. Our past experiences on using nanotechnology to the upstream cases, especially EOR processes, revealed solutions to some of the challenges associated with old EOR techniques. This method that utilizes particles in the order of 1 to100nm brings specific thermal, optical, electrical, rheological and interfacial properties which are directly useful to release the trapped oil from the pore spaces in the order of 5 to 50 microns of tight oil formations. Laboratory tests using nanoparticles as the EOR agent, developing nano computational models to explore the surface properties and utilizing nano-scale analyzing tools such as atomic force microscopy (AFM), scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) mostly for nanoparticles distribution in the pore spaces and on the surfaces for wettability alteration studies are the main parts of this investigation. This paper summarizes new findings from several different theoretical, analytical and experimental works which shows the effectiveness of traditional methods when assisted by this new technology. Ultimately, based on the past experiences, a roadmap will be proposed to avoid the ongoing trial and error practice in this area.

Nanoparticle-Assisted Water-Flooding in Berea Sandstones

“…Recently, the injection of nanoparticles (NP) has been proposed as a potential means to improve reservoir characterisation and to increase oil production, resulting in the term of NanoEOR [3][4][5] .…”

“…The addition or deposition of different nanoparticles could modify the displacing fluid's effective properties such as viscosity [6][7][8] , interfacial tension 9,10 , and dielectric properties 11 ; change the permeability of the rock matrix 12 ; or alter the rock surface wettability 10,13 . In addition, the size-dependent properties (i.e., optical, magnetic, electrical, thermo-physical and interfacial properties) of nanoparticles can be used as sensitive down-hole sensors to target locations that are inaccessible by conventional methods 5,14,15 .…”

Improving the microscopic sweep efficiency of water flooding using silica nanoparticles

“…Based on previous studies, reduction of the interfacial tension between oil and water and alteration of the rock wettability toward water-wet condition can be identified as the chief mechanisms of improving oil recovery by silica nanoparticle (Ayatollahi et al 2012;Roustaei et al 2012;Torsater et al 2012;Giraldo et al 2013). In other words, oil recovery factor can be improved by nanoparticles through various mechanisms from IFT reduction to decreasing the oil viscosity to wettability alteration and improving the mobility ratio (Khademolhosseini et al 2015).…”

“…Nanofluids can increase oil recovery from reservoirs by modifying the rock-fluid and fluid-fluid interfaces during injection in porous media (Ayatollahi et al 2012;.…”

“…Wettability alteration influences and significantly oil recovery were observed for nanoparticles known as hydrophilic polysilicon (Ju and Fan 2009). It has been reported that the adsorption of nanoparticles on pore walls may cause wettability alteration from oil-wet toward more water-wet condition (Ayatollahi 2012;). Onyekonwu and Ogolo (2010) studied capability of three different nanoparticles as an operator to change wettability and oil recovery purposes.…”