Date of Graduation

2016

Document Type

Thesis

Degree Type

MS

College

Statler College of Engineering and Mineral Resources

Department

Petroleum and Natural Gas Engineering

Committee Chair

Huseyin I Bilgesu

Committee Co-Chair

Berna Hascakir

Committee Member

Samuel Ameri

Committee Member

Kashy Aminian

Committee Member

Huseyin I Bilgesu

Committee Member

Berna Hascakir

Abstract

Asphaltenes are fractions of crude oil and precipitate out due to change in pressure, temperature, and composition. Because the most significant pressure and temperature change occur at near wellbore region, asphaltenes precipitation occurs at this area which prevents oil flow due to significant reduction in permeability.;This study investigates the effect of salinity and clay type on asphaltene stability. To reach this goal, the stability of asphaltenes from five different crude oil samples were evaluated after exposing them to different brine concentrations with the absence and presence of porous medium. Porous mediums were prepared by using either Ottawa Sand or Ottawa Sand+Clay mixture. Illite+kaolinite mixture was used as clay. Brine solutions were prepared by either NaCl or CaCl2. For both salts, solutions were prepared by mixing 0.2%, 2%, 4%, 6%, and 8% of salt with deionized water. Asphaltene behavior was visualized for each case under optical microscope. The impact of asphaltene-brine interaction on wettability alteration was determined through contact angle measurements.;Our experimental results suggest that asphaltenes from all five crude oil samples are dispersed in water, and they aligned themselves within water due to their polar-polar interaction with water. In asphaltene-clay-brine systems, divalent salt (CaCl2) interacts more with asphaltenes than monovalent salt (NaCl). Further, increasing salinity promotes clay dispersion which increases the size of asphaltene-clay clusters. Also, the contact angle measurements demonstrated that wettability alters with salinity, however, no direct relation was observed between salinity and asphaltene stability.;This study aimed to characterize the stability of asphaltenes from five different crude oils. Based on crude oils which may aid to produce methods to prevent asphaltenes deposition.

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