Molecular mechanism of viscoelastic polymer enhanced oil recovery in nanopores

Fan, JingCun; Wang, FengChao; Chen, Jie; Zhu, YinBo; Lu, Detang; Liu, He; Wu, Heng An

doi:10.1098/rsos.180076

Cited by 35 publications

(23 citation statements)

References 46 publications

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“…Contact angle is an important criterion for alkali flooding. For chemical EOR process, the reservoir rock should be water wet; otherwise it should be altered from oil wet to water wet by alkali flooding (Fan et al 2018;Vik et al 2018). Wettability depends on contact angle.…”

Section: Contact Anglementioning

confidence: 99%

“…The wettability obtained from DSA 100 was validated with the relative permeability graph obtained from JBN method. In relative permeability curve if the crossover point between non-wetting phase and wetting phase is 50% of water saturation (S w ), then the rock is said to be water wet; otherwise it is oil wet (Fan et al 2018;Berg 2009). Alkali has a strong role over the alteration of wettability.…”

Section: Contact Anglementioning

confidence: 99%

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Effect of alkali on alkali–surfactant flooding in an Upper Assam oil field

Hazarika

Gogoi

2019

J Petrol Explor Prod Technol

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The effect of alkali on immiscible alkali-surfactant (AS) flooding is studied by injecting surfactant individually and surfactant along with alkali. First, reservoir core samples were characterized with the help of X-ray diffraction (XRD), scanning electron microscope (SEM) and thin slide analysis. Based on the clay content of the reservoir, surfactant was selected. Second, AS formulations were designed through dynamic interfacial tension (IFT) and wettability alteration analysis. Third, adsorption of surfactant on porous media was studied with or without alkali to find out the amount of surfactant adsorbed along with the isotherm mechanism. Fourth, core flooding experiments were conducted to find out the recovery efficiency after secondary brine flooding. XRD, SEM and thin slide analysis showed the presence of kaolinite, smectite, illite, silica, quartz in the rock sample. Based on the clay types, sodium dodecyl sulfate (SDS) was selected as surfactant for this study. Ultra-low dynamic IFT in the range of 10 −3 was observed with SDS. Addition of alkali further reduced the IFT of the system. Initially, wettability of the reservoir under study was toward water wet, but during AS flooding it was altered to strongly water wet. Adsorption of surfactant on the porous media was reduced by the application of alkali. During secondary brine flooding, maximum recovery was found to be 49% of Initial Oil in Place. Another 14% of residual oil after secondary flooding was achieved by AS flooding.

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Section: Contact Anglementioning

confidence: 99%

Section: Contact Anglementioning

confidence: 99%

Effect of alkali on alkali–surfactant flooding in an Upper Assam oil field

Hazarika

Gogoi

2019

J Petrol Explor Prod Technol

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“… 12 , 18 There are some other studies stating that polymer solutions possessing viscoelastic characteristics can recover the residual oil in the water-flooded reservoir. 19 − 21 …”

Section: Introductionmentioning

confidence: 99%

Extensional Rheological Measurements of Surfactant–Polymer Mixtures

et al. 2020

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Polymer solutions flowing in the porous media during enhanced oil recovery (EOR) processes are subjected to both shear and extensional rheological deformation. However, the previous rheological studies conducted on a surfactant−polymer (SP) system or polymer systems were only shear-based. In this paper, the extensional rheological performance of hydrolyzed polyacrylamide (HPAM) in the presence of an anionic surfactant at various concentrations (0, 0.01, 0.05, 0.1, 0.2, and 0.3%) is studied with deionized water and 1% NaCl. Further, the extensional rheological behavior of HPAM in the presence of NaCl and CaCl 2 is studied at varying ionic strengths (1−10%). A capillary break-up extensional rheometer is used for performing extensional rheological characterization. Results revealed that the extensional resistance of HPAM is enhanced in the presence of a surfactant. Particularly, around the critical micelle concentration value of the surfactant (0.1%), HPAM showed higher extensional resistance. Higher extensional resistance for the SP system is observed with deionized water when compared to 1% NaCl. HPAM showed improved performance at 1% NaCl salinity when compared to the higher concentration of NaCl salinity. However, the presence of even 1% of calcium ions is detrimental to the extensional properties of HPAM.

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“…and specifically in EOR applications such as polymer flooding [1,[13][14][15][16], Low Salinity Polymer (LSP) flooding [17,18] and Alkaline-Surfactant-Polymer (ASP) flooding [19,20]. In polymer flooding, HPAM viscoelasticity is believed to contribute to higher oil recovery in general and some claim that it might reduce residual oil saturation due to promoting pulling effect mechanisms [21][22][23][24]. HPAM shear thickening behavior may, in some cases, contribute to improving front stability and oil recovery [25].…”

Section: Introductionmentioning

confidence: 99%

Polymer Injectivity: Investigation of Mechanical Degradation of Enhanced Oil Recovery Polymers Using In-Situ Rheology

et al. 2018

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Water soluble polymers have attracted increasing interest in enhanced oil recovery (EOR) processes, especially polymer flooding. Despite the fact that the flow of polymer in porous medium has been a research subject for many decades with numerous publications, there are still some research areas that need progress. The prediction of polymer injectivity remains elusive. Polymers with similar shear viscosity might have different in-situ rheological behaviors and may be exposed to different degrees of mechanical degradation. Hence, determining polymer in-situ rheological behavior is of great significance for defining its utility. In this study, an investigation of rheological properties and mechanical degradation of different partially hydrolyzed polyacrylamide (HPAM) polymers was performed using Bentheimer sandstone outcrop cores. The results show that HPAM in-situ rheology is different from bulk rheology measured by a rheometer. Specifically, shear thickening behavior occurs at high rates, and near-Newtonian behavior is measured at low rates in porous media. This deviates strongly from the rheometer measurements. Polymer molecular weight and concentration influence its viscoelasticity and subsequently its flow characteristics in porous media. Exposure to mechanical degradation by flow at high rate through porous media leads to significant reduction in shear thickening and thereby improved injectivity. More importantly, the degraded polymer maintained in-situ viscosity at low flow rates indicating that improved injectivity can be achieved without compromising viscosity at reservoir flow rates. This is explained by a reduction in viscoelasticity. Mechanical degradation also leads to reduced residual resistance factor (RRF), especially for high polymer concentrations. For some of the polymer injections, successive degradation (increased degradation with transport length in porous media) was observed. The results presented here may be used to optimize polymer injectivity.

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Molecular mechanism of viscoelastic polymer enhanced oil recovery in nanopores

Cited by 35 publications

References 46 publications

Effect of alkali on alkali–surfactant flooding in an Upper Assam oil field

Effect of alkali on alkali–surfactant flooding in an Upper Assam oil field

Extensional Rheological Measurements of Surfactant–Polymer Mixtures

Polymer Injectivity: Investigation of Mechanical Degradation of Enhanced Oil Recovery Polymers Using In-Situ Rheology

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