Determination of Reservoir Rock Wettability by Thin Layer Wicking Approach

Yildiz, Hasan O.; Öztorun, Fatma Bahar; Sirkeci, Ayhan Ali

doi:10.2118/136936-ms

Cited by 3 publications

(1 citation statement)

References 31 publications

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“…This technique is based on modified Washburn and spontaneous liquid imbibition into porous media. Wettability of powders (Siebold et al 2000;Dang-Vu and Hupka 2005;Yildiz et al 2010) and heterogeneous reservoir rocks (Ghedan et al 2010;Ghedan and Canbaz 2014;Aminnaji et al 2015;Canbaz and Ghedan 2015) could be measured using the RIC technique. The contact angles obtained from the RIC technique match the results measured with Amott and USBM methods (Ghedan et al 2010).…”

Section: Introductionmentioning

confidence: 99%

Experimental and modeling study of wettability alteration through seawater injection in limestone: a case study

et al. 2020

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Water flooding is widely applied for pressure maintenance or increasing the oil recovery of reservoirs. The heterogeneity and wettability of formation rocks strongly affect the oil recovery efficiency in carbonate reservoirs. During seawater injection in carbonate formations, the interactions between potential seawater ions and the carbonate rock at a high temperature can alter the wettability to a more water-wet condition. This paper studies the wettability of one of the Iranian carbonate reservoirs which has been under Persian Gulf seawater injection for more than 10 years. The wettability of the rock is determined by indirect contact angle measurement using Rise in Core technique. Further, the characterization of the rock surface is evaluated by molecular kinetic theory (MKT) modeling. The data obtained from experiments show that rocks are undergoing neutral wetting after the aging process. While the wettability of low permeable samples changes to be slightly water-wet, the wettability of the samples with higher permeability remains unchanged after soaking in seawater. Experimental data and MKT analysis indicate that wettability alteration of these carbonate rocks through prolonged seawater injection might be insignificant.

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Section: Introductionmentioning

confidence: 99%

Experimental and modeling study of wettability alteration through seawater injection in limestone: a case study

et al. 2020

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Evaluation of Surfactants Wettability Alteration Using the Washburn Contact Angle Method

Fuseni

Al-Zahrani

Alshehri

et al. 2018

Day 1 Mon, December 10, 2018

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Changes in crude oil wetting of carbonate rock when treated with various surfactants was evaluated using the Washburn method by the sorption of crude oil into packed rock powders. This method served to circumvent the difficulties of direct contact angle measurements on rock-chips where the low interfacial tension between the crude oil and surfactant leads to the spreading and eventual escape of the oil droplet without being attached to the rock chip. Four surfactants were used in the study including an anionic alfa olefin sulfonate, a cationic quaternary ammonium salt, an amphoteric surfactant and a nanosurfactant. Rock powders from a carbonate rock with a mesh size between 80 and 100 were coated with the tested surfactant solutions and compacted in a sample holder for the sorption experiments. Crude oil was raised to the bottom of the powder pack and allowed to rise into the powder by capillarity. A sensitive balance was used to measure the mass of crude oil imbibing into the powder until imbibition ceased. A plot of the square of oil mass against time enabled calculation of the contact angle using the modified Washburn equation. Earlier, a sorption experiment using n-hexane was used to deduce the rock constant for the grain packing, which was necessary for calculation of the crude oil contact angle. The contact angle results demonstrated the surfactant solution's efficiency in altering the crude-oil wetting behavior. An increasing washburn contact angle through coating indicates that the carbonate rock is rendered less oil-wet, which implies better oil displacement. At ambient temperatures, the nanosurfactant gave the highest contact angle implying the least oil-wetting; in second place was the amphoteric surfactant. The anionic surfactant had little effect on oil-wetting while the cationic surfactant decreased oil-wetting to a lesser extent. At higher temperatures, the nanosurfactant maintained its superior effectiveness followed by the cationic and amphoteric surfactants. The anionic surfactant saw little change. The use of sorption to obtain contact angle of crude oil for rock surfaces treated with surfactants eliminates the difficulties associated with direct contact angle measurements for low and ultra-low surfactant solutions where attachment an oil-droplet is almost impossible. With the Washburn method rapid evaluation of surfactants ability to change rocks wettability can be made to better guide further evaluations of such processes. As the washburn method measures contact angle between solids and a liquid surrounded by air, the contact angles obtained are not to be interpreted directly as those obtained in a liquid-liquid environment.

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Investigation of Wettability Alteration Processes for Carbonates using the Washburn Contact Angle Method with Two Sorption Fluids

AlSofi

Kaidar

Fuseni

2020

Day 1 Mon, January 13, 2020

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We investigated the utility of a modified Washburn method, combining results of two sorption experiments, to study wettability alteration processes. The main objective in deploying this technique was to avoid the difficulty of direct contact angle measurements in surfactant solutions. In such cases, the ultra-low interfacial tension between the crude oil and surfactant tends to cause the oil drop to spread prematurely rendering the measurement unreliable if possible at all. A carbonate-rock, dead crude oil, synthetic brines including SmartWater, and five surfactants were used in this study. The surfactants included: an anionic alfa olefin sulfonate, a cationic quaternary ammonium salt, an amphoteric surfactant, a nanosurfactant, and a nonionic ethoxylated alchohol. Hexane was also used as a reference completely wetting fluid. For sorption experiments, the rock was powdered. The powder with size between 80 and 100 mesh was compacted in the sample holder. In each experiment, a given fluid was raised to the bottom of the powder pack and allowed to rise into the powder by capillarity. A sensitive balance was used to measure fluid imbibition into the powder until no more fluid imbibes. Beside sorption experiments, surface and interfacial tension measurements were made. For benchmarking, we relied on previous findings reported in the literature. Plotting the square of fluid mass against time gave a slope which enabled the calculation of contact angle in air. The results (slope) observed for the completely wetting fluid (hexane) provided the rock constant. Sorption results of crude oil coupled with the previously determined rock constant enabled estimation of the Wasburn oil/air contact angles using the modified Washburn equation. Sorption results with brine and surfactant solutions coupled with the rock constant and oil/air enabled estimation of the Washburn water/air contact angles using the modified Washburn equation. Based on water/air and oil/air contact angles, values of the conventional oil/water contact angle were estimated. For surfactant solutions, interfacial tension between oil and surfactant-free brine were used to approximate contact angles that were otherwise undefined. This approach, enabled a robust and rapid estimation of the effects of various processes on contact angles (hence wettability alteration). Based on the benchmark previous findings, the sorption approach yielded acceptable results especially for screening purposes. The results demonstrated the potential of the Smartwater recipe and the nonionic surfactant for wettability alteration. However, it is recommended to rely on the sorption method direct measurements including sorption rates to establish sorption-based wettability indices and eliminate the intermediary and probably unnecessary contact-angle estimation step. In conclusion, the use of sorption to obtain contact-angle estimates provide a novel rapid and robust procedure for evaluation and screening of wettability-alteration agents. This eliminates direct contact angle measurements that are often cumbersome. It specifically eliminate the difficulties of attaching an oil drop onto a rock surface immersed in surfactant solutions.

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Determination of Reservoir Rock Wettability by Thin Layer Wicking Approach

Cited by 3 publications

References 31 publications

Experimental and modeling study of wettability alteration through seawater injection in limestone: a case study

Experimental and modeling study of wettability alteration through seawater injection in limestone: a case study

Evaluation of Surfactants Wettability Alteration Using the Washburn Contact Angle Method

Investigation of Wettability Alteration Processes for Carbonates using the Washburn Contact Angle Method with Two Sorption Fluids

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