Optimizing Electroosmotic Flow Potential for Electrically Enhanced Oil Recovery (EEORTM) in Carbonate Rock formations of Abu Dhabi Based on Rock Properties and Composition

Abstract

TX 75083-3836, U.S.A., fax +1-972-952-9435. AbstractAmong the leading emerging technologies for in-situ oil recovery is the use of an electrokinetic technology known as electrically enhanced oil recovery (EEOR TM ) i . Electrokinetic methods are continually tested and improved both in the laboratory and in the field to render them highly feasible for increased oil recovery. The effectiveness of the process to enhance the flow and production of both light and heavy crude oil from sandstone reservoirs have been demonstrated in the laboratory by researchers for the last four decades. Successful but limited field applications, both in-situ and ex-situ have also been reported for the same duration of time. There has been little work done on the applicability of the technology to carbonate rock reservoirs, owing to predicted high energy consumption due to low clay content formations and high salinity environments. Yet, compared to currently incurred high costs of conventional electrical oil recovery which depends on joule heating of the formation , electroosmotic mass transport may offer a feasible option to augment the flow of these large volumes of crude oil both onshore and offshore.A great additional incentive is that EEOR TM can be engineered as a truly green technology, where there is no water consumption, and no air, water, and formation pollution. The technology can be applied with no depth limitation in-situ rendering it even more attractive in remote operating locations as well as the environmentally challenging ones. This paper addresses the first attempt undertaken at the newly-established Electrokinetic Laboratory of the Petroleum Institute in Abu Dhabi, U.A.E. to determine the efficacy of electrokinetic technology in EEOR TM tested on field collected data samples of Abu Dhabi. The results of the initial tests conducted on field retrieved specimens of Abu Dhabi on-shore carbonate reservoir rock candidates from several formations in high salinity environments that contained various crude types are reported.

Electrokinetics Technology to Improve Acidizing of Carbonate Reservoir Rocks

“…In tight formations, e may exceed k considerably. The feasibility of application of D.C. current in carbonate reservoir rocks with acids was demonstrated by Haroun et al (2009) [7]. …”

“…As the experimental data obtained by the writers indicate, the injection rate q i , can be increased considerably by application of D.C. current (electrokinetic effect, Figure 1) [2][3][4]. The application of D.C. electrokinetics in Abu Dhabi carbonate reservoir rocks has been proven to be very promising by the authors [7].…”

Electrokinetic Driven Low-Concentration Acid Improved Oil Recovery in Abu Dhabi Tight Carbonate Reservoirs

“…When oil and brine flow simultaneously in a porous medium, the flow of fluid through the core can be established as the imposed electrical potential gradient (E) is in the same direction as the pressure drop. Hence, the total flow rate (q t ) is the addition of the electroosmotic relation with the Darcy equation [26,[32][33]. If an electric potential is applied across the core, the electroosmotic flow rate of the brine will increase as the electric field will drive the cations in the mobile part of the double layer towards the cathode.…”

“…The electroosmotic flow rate increases with increase in ion concentration, valence number and applied electric potential, whereas it decreases with increasing formation resistivity factor. The salinity of water has a direct effect due to higher conductivity allowing increased electrokinetic effects and therefore, increasing fluid transport [25][26]. In addition, high salinity provides increased buffering capacity which can alleviate the acid formation at the positive electrode (anode) and its ultimate migration through the core.…”

“…Five mechanisms appear to influence EK-EOR including Joule heating, electromigration, electrophoresis, electroosmosis and electrochemically enhanced reactions. All of these mechanisms are collectively called electrokinetics and contribute to oil mobility and permeability enhancement [19,[21][22][23][24][25][26].…”