Thickening Carbon Dioxide With the Fluoroacrylate-Styrene Copolymer

Xu, Jiarui; Wlaschin, Aaron P; Enick, Robert M.

doi:10.2118/84949-pa

Cited by 54 publications

(43 citation statements)

References 18 publications

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“…Our group has used this procedure previously to determine the effectiveness of a polyfluoroacrylate− styrene copolymer to thicken CO 2 . 3, 9 We have recently shown 27 that the average shear rate over the surface of the falling ball in our system is…”

Section: ■ Experimental Sectionmentioning

confidence: 77%

Anthraquinone Siloxanes as Thickening Agents for Supercritical CO₂

et al. 2016

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A series of aromatic amide-functionalized, low-molecular-weight polydimethylsiloxanes were synthesized, and their solubility and thickening ability in supercritical carbon dioxide (scCO 2 ) were evaluated. Amide-terminated polydimethylsiloxane (PDMS) oligomers with simple or electron-rich aromatic groups were found to be moderate viscosity oils, indicating that the end groups do not interact strongly enough to be thickeners. Attachment of electron-deficient aromatic groups, such as 4-nitrophenyl, biphenyl, or anthraquinone, onto these amides produced solid polysiloxanes, even at relatively higher degrees of polymerization on the PDMS core (x = 40−50). PDMS derivatives with anthraquinone-2-carboxamide (AQCA) end groups were clear, somewhat rubbery solids. These compounds were found to act as thickeners and gelators of hexanes. In addition, they were able to thicken and/or gel mixtures of hexane and scCO 2 . The best results were obtained with an AQCA-terminated branched PDMS. Branched fluorenone-2-carboxamide was found to be a waxy solid that was very soluble and, therefore, not a thickener for hexane, and fluorenone-4-carboxamide was a viscous oil, indicating that these amide groups did not interact sufficiently to be useful. 10,10-Dioxothioxanthone-2-carboxamides were more efficient gelators of hexane than anthraquinone-2-carboxamides. However, they were not sufficiently soluble in scCO 2 , even in the presence of hexane co-solvent, to be useful as thickeners. ■ INTRODUCTIONThere has been a steady increase in CO 2 flooding and steam flooding enhanced oil recovery (EOR) techniques in recent decades, with the injection of high-pressure CO 2 recently becoming the most prominent EOR method in the U.S. 1 High-pressure CO 2 can extract light components from crude oil because it reduces CO 2 −oil interfacial tension and forms a CO 2 -rich solution that is an excellent solvent for the crude oil ahead of it. Further, CO 2 swells the oil and reduces oil viscosity. Although not as strong of a solvent as propane, natural gas liquids (NGL), or liquefied petroleum gas (LPG), the U.S. has several prolific subterranean formations containing high-pressure, high-purity CO 2 that enable massive amounts of this fluid to be available at a relatively low cost. However, the viscosity of supercritical CO 2 at typical operating conditions is roughly 10−100 times less than that of the light oil being displaced. Therefore, this oil displacement process is plagued by viscous fingering of CO 2 through the sandstone or carbonate rock. This results in a high CO 2 use rate, a disappointingly low oil production rate, and the recompression and recycle of large volumes of CO 2 . About 90% of the CO 2 flooding projects in the U.S. mitigate the high CO 2 mobility by co-injecting water, which reduces the CO 2 saturation (i.e., volume percent of CO 2 in the pores) and thereby lowers the relative permeability of CO 2 . The presence of the increased water in the pores may make it more difficult for the CO 2 and oil phases to contact one another, 2 but ...

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Section: ■ Experimental Sectionmentioning

confidence: 77%

Anthraquinone Siloxanes as Thickening Agents for Supercritical CO₂

et al. 2016

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“…Enick, Beckman, and co-workers then developed an associative co-polymeric thickener based on a perfluoropolyacrylate in the hope of reducing the amount of thickener needed to attain a specified viscosity [Xu and Enick, 2001;Xu et al, 2003;Huang et al, 2000]. The most effective thickener was a random co-polymer composed of ~79 mol% of a CO 2 -philic fluoroacrylate monomer (1-,1-,2-,2-tetrahydro heptadecafluorodecylacrylate) and 21mol% of a mildly CO 2 -phobic monomer with a pendant associating group-styrene (polyFluoroAcrylateSTyrene or polyFAST).…”

Section: Polymeric Thickenersmentioning

confidence: 99%

Development of Small Molecule CO2 Thickeners for EOR and Fracturing

Lee

Cummings

Dhuwe

et al. 2014

SPE Improved Oil Recovery Symposium

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The ideal carbon dioxide (CO 2 ) thickener would be an affordable, safe, water-insoluble additive that could dissolve in CO 2 at typical wellhead and reservoir conditions during CO 2 enhanced oil recovery (EOR) and elevate the viscosity of CO 2 to the same value as the oil. Further, the additive would not require heating or an organic co-solvent to achieve dissolution. A CO 2 thickener could be a transformative technology in that it would eliminate unfavorable mobility ratios during CO 2 EOR and reduce or eliminate the need for WAG. A detailed history of prior attempts to thicken CO 2 with either high molecular weight polymers or small associating compounds is presented. Our strategy for designing a novel small molecule CO 2 thickener is then detailed. Each thickener candidate contains a strongly CO 2 -philic segment (e.g. a very short polymer or oligomer of silicone oil or polyprolylene glycol), and one or more somewhat CO 2 -phobic functional groups that induces intermolecular interactions that can lead to the formation of viscosity-enhancing supramolecular structures in solution.

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“…We have shown before that oil recovery increases as the solvent slug size decreases. 24 The solvent slug size was kept constant at 1% PV in this set of experiments. Fig.…”

Section: Pv Solvent Injectionmentioning

confidence: 99%

“…In fact, there are four proposed methods for sweep improvement in gas flooding: water-alternating-gas, 22 foams, 23 direct thickeners, 24 and dynamic profile control in wells. 25 To evaluate any sweep improvement methods, one needs controlled field-testing.…”

Section: Introductionmentioning

confidence: 99%

Sweep Efficiency of Miscible Floods in a High-Pressure Quarter Five-Spot Model

2006

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TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractEvaluation and improvement of sweep efficiency are important for miscible displacement of medium viscosity oils. A high-pressure quarter 5-spot cell was used to conduct multicontact miscible water-alternating-gas (WAG) displacements at reservoir conditions. A dead reservoir oil (78 cp) was displaced by ethane. The minimum miscibility pressure for ethane with the reservoir oil is between 630 and 1000 psi. Gasflood followed by waterflood improves the oil recovery over just waterflood in the quarter 5-spot. As the pressure decreases, the gasflood oil recovery increases in the pressure range of 660-1380 psi for this undersaturated viscous oil. WAG improves the oil recovery in the quarter 5-spot over the continuous gas injection followed by waterflood. WAG injection slows down gas breakthrough. A decrease in the solvent amount lowers the oil recovery in WAG floods, but significantly higher amount of oil can be recovered with 0.1 PV solvent injection over only waterflood. Use of a horizontal production well lowers the oil recovery slightly over the vertical production well during WAG injection. Sweep efficiency is higher for lower reservoir pressure (in this undersaturated oil), for 9-spot pattern, and for 1:1 WAG injection compared to continuous gas injection followed by waterflood in the 5-spot model.

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Thickening Carbon Dioxide With the Fluoroacrylate-Styrene Copolymer

Cited by 54 publications

References 18 publications

Anthraquinone Siloxanes as Thickening Agents for Supercritical CO₂

Anthraquinone Siloxanes as Thickening Agents for Supercritical CO₂

Development of Small Molecule CO2 Thickeners for EOR and Fracturing

Sweep Efficiency of Miscible Floods in a High-Pressure Quarter Five-Spot Model

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Thickening Carbon Dioxide With the Fluoroacrylate-Styrene Copolymer

Cited by 54 publications

References 18 publications

Anthraquinone Siloxanes as Thickening Agents for Supercritical CO2

Anthraquinone Siloxanes as Thickening Agents for Supercritical CO2

Development of Small Molecule CO2 Thickeners for EOR and Fracturing

Sweep Efficiency of Miscible Floods in a High-Pressure Quarter Five-Spot Model

Contact Info

Product

Resources

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Anthraquinone Siloxanes as Thickening Agents for Supercritical CO₂

Anthraquinone Siloxanes as Thickening Agents for Supercritical CO₂