Experimental Study on Direct Current Voltage Assisted Carbonated Water-Flooding Mechanism in Tight Oil Reservoir

Abstract Tight oil reservoir plays an increasingly important role in the world energy system, but its recovery is always so low. Hence, a more effective enhanced oil recovery (EOR) technology is urgently needed. Meanwhile, greenhouse effect is more and more serious, a more effective carbon capture and sequestration (CCS) method is also badly needed. Direct current voltage assisted carbonated water-flooding is a new technology that combines direct current voltage with carbonated water-flooding to enhance oil recovery and CO2 sequestration efficiency, simultaneously. Experimental studies were conducted from macroscopic-scale to microscopic-scale to study the performance and mechanism of direct current voltage assisted carbonated water-flooding. Firstly, core flood experiments were implemented to study the effect of direct current voltage assisted carbonated water on oil recovery and CO2 sequestration efficiency. Secondly, contact angle and interfacial tension/dilatational rheology were measured to analyze the effect of direct current voltage assisted carbonated water on crude oil-water-rock interaction. Thirdly, total organic carbon (TOC), gas chromatography (GC), and electrospray ionization-fourier transform ion cyclotron resonance-mass spectrometry (ESI FT ICR-MS) were used to investigate the organic composition change of produced effluents and crude oil in direct current voltage assisted carbonated water treatment. Through direct current voltage assisted carbonated water-flooding experiments, the following results can be obtained. Firstly, direct current voltage assisted carbonated waterflooding showed greater EOR capacity and CO2 sequestration efficiency than individual carbonated water and direct current voltage treatment. With the increase of direct current voltage, oil recovery increases to 38.67% at 1.6V/cm which much higher than 29.07% of carbonated water-flooding and then decreases, meanwhile, CO2 output decreases to only 35.5% at 1.6V/cm which much lower than 45.6% of carbonated water-flooding and then increases. Secondly, in direct current voltage assisted carbonated water-flooding, the wettability alteration is mainly caused by carbonated water and the effect of direct current can be neglected. While both carbonated water and direct current have evident influence on interfacial properties. Herein, with direct current voltage increasing, the interfacial tension firstly decreases and then increases, the interfacial viscoelasticity initially strengthens and then weakens. Thirdly, GC results indicated that crude oil cracking into lighter components occurs during direct current voltage assisted carbonated water-flooding, with the short-chain organic components increasing and the long-chain components decreasing. Meanwhile, TOC and ESI FT ICR-MS results illustrated that CO2 electroreduction do occur in direct current voltage assisted carbonated water-flooding with the dissolved organic molecules increases and the emergence of formic acid. Conclusively, the synergy of CO2 electrochemical reduction into formic acid in aqueous solution and the long-chain molecules electrostimulation pyrolysis into short ones in crude oil mutually resulted in the enhancement of crude oil-carbonated water interaction. This paper proposed a new EOR & CCS technology-direct current voltage assisted carbonated water-flooding. It showed great research and application potential on tight oil development and greenhouse gas control. More work needs to be done to further explore its mechanism. This paper constructs a multiscale & interdisciplinary research system to study the multidisciplinary (EOR&CCS) problem. Specifically, a series connected physical (Core displacement, Contact angle, and Interfacial tension/rheology measurements) and chemistry (TOC, GS, and ESI FT ICR-MS) experiments are combined to explore its regularity and several physics (Atomic physics) and chemistry (Electrochemistry/Inorganic Chemistry) theories are applied to explain its mechanisms.

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Energy Flux on a Micromotor Operating under Stationary Direct Current Voltage

Colloids and Surfaces A Physicochemical and Engineering Aspects ◽

10.1016/j.colsurfa.2021.127197 ◽

2021 ◽

pp. 127197

Author(s):

Wenyu Zhang ◽

Kohei Ohara ◽

Yasunao Okamoto ◽

Erika Nawa-Okita ◽

Daigo Yamamoto ◽

...

Keyword(s):

Energy Flux ◽

Direct Current ◽

Current Voltage ◽

Direct Current Voltage

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Effect and Mechanism of CO2 Electrochemical Reduction for CCUS-EOR

10.2118/206135-ms ◽

2021 ◽

Author(s):

Rukaun Chai ◽

Yuetian Liu ◽

Qianjun Liu ◽

Xuan He ◽

Pingtian Fan

Keyword(s):

Contact Angle ◽

Crude Oil ◽

Electrochemical Reduction ◽

1H Nmr ◽

Oil Recovery ◽

Co2 Sequestration ◽

Sno2 Nanoparticles ◽

Wettability Alteration ◽

X Ray ◽

Electrochemical Conversion

Abstract Unconventional reservoir plays an increasingly important role in the world energy system, but its recovery is always quite low. Therefore, the economic and effective enhanced oil recovery (EOR) technology is urgently required. Moreover, with the aggravation of greenhouse effect, carbon neutrality has become the human consensus. How to sequestrate CO2 more economically and effectively has aroused wide concerns. Carbon Capture, Utilization and Storage (CCUS)-EOR is a win-win technology, which can not only enhance oil recovery but also increase CO2 sequestration efficiency. However, current CCUS-EOR technologies usually face serious gas channeling which finally result in the poor performance on both EOR and CCUS. This study introduced CO2 electrochemical conversion into CCUS-EOR, which successively combines CO2 electrochemical reduction and crude oil electrocatalytic cracking both achieves EOR and CCUS. In this study, multiscale experiments were conducted to study the effect and mechanism of CO2 electrochemical reduction for CCUS-EOR. Firstly, the catalyst and catalytic electrode were synthetized and then were characterized by using scanning electron microscope (SEM) & energy dispersive X-ray spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS). Then, electrolysis experiment & liquid-state nuclear magnetic resonance (1H NMR) experiments were implemented to study the mechanism of CO2 electrochemical reduction. And electrolysis experiment & gas chromatography (GC) & viscosity & density experiments were used to investigate the mechanism of crude oil electrocatalytic cracking. Finally, contact angle and coreflooding experiments were respectively conducted to study the effect of the proposed technology on wettability and CCUS-EOR. SEM & EDS & XPS results confirmed that the high pure SnO2 nanoparticles with the hierarchical, porous structure, and the large surface area were synthetized. Electrolysis & 1H NMR experiment showed that CO2 has converted into formate with the catalysis of SnO2 nanoparticles. Electrolysis & GC & Density & Viscosity experiments indicated that the crude oil was electrocatalytically cracked into the light components (<C20) from the heavy components (C21∼C37). As voltage increases from 2.0V to 7.0V, the intensity of CO2 electrocchemical reduction and crude oil electrocatalytic cracking enhances to maximum at 3.5V (i.e., formate concentration reaches 6.45mmol/L and carbon peak decreases from C17 to C15) and then weakens. Contact angle results indicated that CO2 electrochemical reduction and crude oil electocatalytic cracking work jointly to promote wettability alteration. Thereof, CO2 electrochemical reduction effect is dominant. Coreflooding results indicated that CO2 electrochemical reduction technology has great potential on EOR and CCUS. With the SnO2 catalytic electrode at optimal voltage (3.5V), the additional recovery reaches 9.2% and CO2 sequestration efficiency is as high as 72.07%. This paper introduced CO2 electrochemical conversion into CCUS-EOR, which successfully combines CO2 electrochemical reduction and crude oil electrocatalytic cracking into one technology. It shows great potential on CCUS-EOR and more studies are required to reveal its in-depth mechanisms.

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Comparing Crude Oils with Different API Gravities on a Molecular Level Using Mass Spectrometric Analysis. Part 1: Whole Crude Oil

Energies ◽

10.3390/en11102766 ◽

2018 ◽

Vol 11 (10) ◽

pp. 2766 ◽

Cited By ~ 6

Author(s):

Jandyson Santos ◽

Alberto Wisniewski Jr. ◽

Marcos Eberlin ◽

Wolfgang Schrader

Keyword(s):

Crude Oil ◽

Atmospheric Pressure ◽

Molecular Level ◽

Carbon Number ◽

Mass Spectrometric ◽

Oil Refining ◽

Crude Oils ◽

Spectrometric Analysis ◽

Ft Icr Ms ◽

Ft Icr

Different ionization techniques based on different principles have been applied for the direct mass spectrometric (MS) analysis of crude oils providing composition profiles. Such profiles have been used to infer a number of crude oil properties. We have tested the ability of two major atmospheric pressure ionization techniques, electrospray ionization (ESI(±)) and atmospheric pressure photoionization (APPI(+)), in conjunction with Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS). The ultrahigh resolution and accuracy measurements of FT-ICR MS allow for the correlation of mass spectrometric (MS) data with crude oil American Petroleum Institute (API) gravities, which is a major quality parameter used to guide crude oil refining, and represents a value of the density of a crude oil. The double bond equivalent (DBE) distribution as a function of the classes of constituents, as well as the carbon numbers as measured by the carbon number distributions, were examined to correlate the API gravities of heavy, medium, and light crude oils with molecular FT-ICR MS data. An aromaticity tendency was found to directly correlate the FT-ICR MS data with API gravities, regardless of the ionization technique used. This means that an analysis on the molecular level can explain the differences between a heavy and a light crude oil on the basis of the aromaticity of the compounds in different classes. This tendency of FT-ICR MS with all three techniques, namely, ESI(+), ESI(−), and APPI(+), indicates that the molecular composition of the constituents of crude oils is directly associated with API gravity.

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