Effect of Rock Mineralogy and Oil Composition on Wettability Alteration and Interfacial Tension by Brine and Carbonated Water (original) (raw)
Wettability has a significant impact on flow of oil during enhanced oil recovery (EOR) and profound effect on fluids 14 distribution in oil fields. Mechanisms that influence the interaction between the injected water and the components of 15 crude oil in the presence of carbonate rock sample were investigated. The main objectives of this study were to investigate 16 the role of both rock mineralogy and the compositions of various oils as a function of asphaltenes content on the 17 destabilization of the aqueous film separating the oil from substrate rock surface of carbonate using aqueous phases such 18 brine and carbonated water. The contact angles as a function of time were measured using brine and carbonated water 19 and two types of crude oils on four types of rock samples. Once the exact contact angle has been determined, the 20 compositions of various oils, based on asphaltenes contents, were characterized to investigate the role of oil composition 21 on the destabilization of the aqueous film separating the oil from rock surface. Interfacial tensions of brine and crude oils 22 were also measured. Four types of rock samples from carbonate reservoirs, with different compositions, selected based 23 on XRD results were: (1) 100% Dolomite D (100), (2) 100% Calcite C (100), (3) 67% Dolomite + 33% Calcite (D67 + 24 C33), and (4) 37% Dolomite + 63% Calcite (D37 + C63). Two types of crude oil were used based on asphaltenes content 25 obtained using SARA analysis. The contents of asphaltenes for the crude-1 and crude-2 were 11.6 and 6.4 wt% and 26 represented as (I-11.6) and (II-6.4), respectively. In this study, crude oil/brine/carbonate systems showed that (D37 + 27 C63) gave the lowest contact angle value of 67 o with 6.4 wt% of asphaltenes content (II-6.4), and D (100) gave the highest ACS Paragon Plus Environment Energy & Fuels 2 1 adhesion tension was shifting to positive directions as degree of water wetness was increasing. This behavior was mainly 2 due to the effect of type-II crude oil. 3 The novelty of this study stems from studying the effect of rock mineralogy based on Dolomite and Calcite distribution 4 and oil composition based on asphaltenes content in wettability alteration using aqueous phases such as brine and 5 carbonated water. The results of both contact angle and IFT were implemented in adhesion tension using Thomas Young 6 equation (Adamson, 1982) as an alternative approach in defining surface wettability. This study will provide a better 7 understanding of mineralogy/fluid/ interaction which is very crucial in the optimization of water injection and wettability 8 reversal during enhanced oil recovery process.
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