Rheology and Phase Behavior of Carbon Dioxide and Crude Oil Mixtures

Hu, Ruien; Crawshaw, John; Trusler, J. P. Martin; Boek, Edo S.

doi:10.1021/acs.energyfuels.6b01858

Cited by 19 publications

(23 citation statements)

References 44 publications

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“…In this region, as shown in Figure 4, the slope of the flow curve changed from positive to negative. This lower value of viscosity was substantially below the viscosity of the oil phase (5380 mPa•s at 50 °C and ambient pressure [10]), indicating that the emulsion may undergone a phase inversion. Phase inversion is the phenomenon whereby a phase interchange occurs in a liquid-liquid emulsion [11].…”

Section: Figure 4 Andmentioning

confidence: 83%

Effect of CO₂ Dissolution on the Rheology of a Heavy Oil/Water Emulsion

Trusler

Crawshaw

2016

Energy Fuels

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KEYWORDSRheology, heavy crude oil, emulsion, carbon dioxide, viscosity, non-Newtonian fluid ABSTRACT During the later stages of flow from an oil well, water inevitably appears in the produced fluids.When crude oil and water are energetically mixed by constrictions in the production tubing, emulsions can form. Heavy crudes may also contain surface-active agents that can stabilise the emulsion, resulting in persistent flow problems. If carbon dioxide is injected into such a reservoir (e.g. for CO2 EOR), then the CO2 will dissolve into both oil and water phases affecting the emulsion properties, however this aspect has been neglected in the literature so far.2 This paper presents a study of the rheology of oil/water emulsion altered by carbon dioxide. The emulsion was prepared by blending 50 wt% water and 50 wt% Zuata heavy crude oil in a high shear mixer (Silverson), resulting in a water-in-oil emulsion. The emulsion was subsequently stable at ambient conditions for several weeks without the addition of any surfactants. A high pressure rheometer system coupled to a mixing vessel and fluid circulation loop allowed the emulsion to be brought into equilibrium with CO2 and its rheology was then measured at a temperature of 50 °C and at pressures from ambient to 120 bar. The emulsion without dissolved CO2 was found to be slightly shear thinning below a critical shear rate, above which the viscosity jumped to a much lower value. The CO2 dissolution had two effects: first, it reduced the emulsion viscosity at low shear while preserving the shear thinning behaviour; second, increasing the CO2 pressure in equilibrium with the emulsion increased the critical shear rate at which the viscosity jump occurred. At shear rates above the jump, the emulsion viscosity dropped to a level lower than that of the original continuous phase (oil). It is likely that the viscosity jump occurred due to phase inversion; however, this was difficult to observe directly. The jump was reversed (with some hysteresis) as the shear rate was reduced again. The dissolved CO2 can influence the emulsion properties such as phase inversion through its action in both phases. The dissolution of CO2 in the oil phase reduced the viscosity of the oil while dissolution into the water phase markedly changed pH and thereby the performance of any charged surface-active agents present in the crude oil.

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Section: Figure 4 Andmentioning

confidence: 83%

Effect of CO₂ Dissolution on the Rheology of a Heavy Oil/Water Emulsion

Trusler

Crawshaw

2016

Energy Fuels

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Section: Representative Resultsmentioning

confidence: 99%

“…– –, measurement fluctuation range; , ambient pressure; , 20 bar; , 40 bar; , 60 bar; , 80 bar; , 100 bar; , 120 bar; , 140 bar; , 160 bar; , 180 bar; , 220 bar. Reprinted with permission from Hu et al 15 . Copyright 2016 American Chemical Society.…”

Section: Representative Resultsmentioning

confidence: 99%

Measurement of the Rheology of Crude Oil in Equilibrium with CO<sub>2</sub> at Reservoir Conditions

Hu¹,

Crawshaw²

2017

JoVE

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A rheometer system to measure the rheology of crude oil in equilibrium with carbon dioxide (CO2) at high temperatures and pressures is described. The system comprises a high-pressure rheometer which is connected to a circulation loop. The rheometer has a rotational flow-through measurement cell with two alternative geometries: coaxial cylinder and double gap. The circulation loop contains a mixer, to bring the crude oil sample into equilibrium with CO2, and a gear pump that transports the mixture from the mixer to the rheometer and recycles it back to the mixer. The CO2 and crude oil are brought to equilibrium by stirring and circulation and the rheology of the saturated mixture is measured by the rheometer. The system is used to measure the rheological properties of Zuata crude oil (and its toluene dilution) in equilibrium with CO2 at elevated pressures up to 220 bar and a temperature of 50 °C. The results show that CO2 addition changes the oil rheology significantly, initially reducing the viscosity as the CO2 pressure is increased and then increasing the viscosity above a threshold pressure. The non-Newtonian response of the crude is also seen to change with the addition of CO2.

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“…Oil viscosity is reduced due to the partitioning of CO2 into oil, making oil lighter and increasing its mobility in porous media. When an oil contact with CO2 at high pressures, the non-Newtonian behavior of the crude oil was diminished and ultimately disappeared [23]. The primary parameter in the reduction of oil viscosity is the concentration of CO2 in the oil.…”

Section: Oil Swellingmentioning

confidence: 99%

“…However, they did not report the properties of different crude oils used in the experimental procedure. Hu et al [23] measured the mixture viscosity for heavy oil using a highpressure circulation system and measured rheological properties of CO2-oil mixture such as shear rate. They also reported phase behavior measurements of the CO2-oil mixture.…”

Section: Oil Swellingmentioning

confidence: 99%

Numerical Mechanistic Study of In-Situ CO2 EOR – Kinetics and Recovery Performance Analysis

Hussain

Shiau

2021

SPE Annual Technical Conference and Exhibition

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The success of supercritical CO2 Enhanced Oil Recovery (EOR) cannot be duplicated if the cost of CO2 transposition and processing becomes prohibitive. Research results of the in-situ CO2 EOR (ICE) approach offered a potential technology for many waterflooded stripper wells that lack access to affordable CO2 sources. Previously the ICE synergetic mechanisms were only qualitatively attributed to oil swelling and viscosity reduction due to the preferential partition of CO2 into the oleic phase. This study aims to quantify the contributions to recovery factors from several plausible mechanisms with numerical modeling and simulation. First, the urea reaction was modeled as the CO2 generating chemical decomposing to CO2 and ammonia in the reservoir conditions. The CO2 partitions into oil, which leads to the reaction continuation to generate more CO2. The resulting ammonia largely left in water may further react with certain crudes to generate surfactants, thus, decrease the oil/water interfacial tension (IFT). It is expected that the oil containing CO2 also has a lower IFT with water. The reaction kinetics under different temperatures were incorporated into the numerical model. A numerical model featuring the synergetic mechanisms was built including stoichiometry and kinetics of urea reaction, oil swelling effect, oil viscosity reduction, and IFT reduction effect on the relative permeabilities. The laboratory experiments, pore volume injection versus oil saturation were history matched for three different oils including Dodecane, Earlsboro oil, and DeepStar oil. The phase behavior was modeled with the equation of state (EOS) under different mole fractions of CO2. The reaction kinetics were also modified to history match the laboratory experiment. The estimated reduction of oil viscosity was calculated, 76% for Earlsboro oil, 91% in DeepStar oil, and 75% in dodecane oil. The oil swelling factors ranged from 1.60% to 19% in the three lab models, which translates to the recovery factor of oil. The endpoints of relative permeability were modified to account for the recovery contribution to the IFT and viscosity reduction. The impact of reaction kinetics on oil swelling and recovery factor was also determined, and they are not numerically close to reaction kinetics used in the lab cases. The matched reaction kinetics, activation energy and reaction frequency factor for the dodecane laboratory experiment were 91.80 kJ/gmol and 6.5E+09 min−1. The study concluded that the incremental recovery due to oil swelling ranges between 3.16% and 18.30%, and then from 12.91% to 41.59% is due to IFT reduction for all the cases. The relative permeability and urea reaction kinetics remained the most uncertain parameters during history matching and modeling the ICE synergetic mechanisms.

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Rheology and Phase Behavior of Carbon Dioxide and Crude Oil Mixtures

Cited by 19 publications

References 44 publications

Effect of CO₂ Dissolution on the Rheology of a Heavy Oil/Water Emulsion

Effect of CO₂ Dissolution on the Rheology of a Heavy Oil/Water Emulsion

Measurement of the Rheology of Crude Oil in Equilibrium with CO<sub>2</sub> at Reservoir Conditions

Numerical Mechanistic Study of In-Situ CO2 EOR – Kinetics and Recovery Performance Analysis

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Rheology and Phase Behavior of Carbon Dioxide and Crude Oil Mixtures

Cited by 19 publications

References 44 publications

Effect of CO2 Dissolution on the Rheology of a Heavy Oil/Water Emulsion

Effect of CO2 Dissolution on the Rheology of a Heavy Oil/Water Emulsion

Measurement of the Rheology of Crude Oil in Equilibrium with CO<sub>2</sub> at Reservoir Conditions

Numerical Mechanistic Study of In-Situ CO2 EOR – Kinetics and Recovery Performance Analysis

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Effect of CO₂ Dissolution on the Rheology of a Heavy Oil/Water Emulsion

Effect of CO₂ Dissolution on the Rheology of a Heavy Oil/Water Emulsion