Petroleum Engineering
Bardiya Yazdani; Amir Hossein Saeedi Dehaghani
Abstract
This research aims to investigate the effect of microwaves on the physical and chemical properties of heavy crude oil in the presence of different minerals. In this regard, the physical and chemical changes of the oil and rock powder (sand and carbonate) mixture are investigated by microwave radiation. ...
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This research aims to investigate the effect of microwaves on the physical and chemical properties of heavy crude oil in the presence of different minerals. In this regard, the physical and chemical changes of the oil and rock powder (sand and carbonate) mixture are investigated by microwave radiation. Viscosity and temperature changes of two samples are measured. IP143 and elemental analysis (carbon, hydrogen, nitrogen, and sulfur) are used to extract and identify the composition changes of asphaltene. The viscosity and temperature changes show that for both samples at the beginning of microwave radiation, there is a decrease in viscosity due to heavy hydrocarbon particle cracking, such as asphaltene, and converting them into lighter ones. Light compounds evaporate by continuing the radiation and temperature increase; finally, the viscosity increases. The evaporation process in the carbonate powder sample starts earlier than in the sand powder. From elemental analysis, it is concluded that the sulfur and nitrogen in asphaltene decrease almost the same for both samples, and this decrease is more evident for sulfur; thus, the rock powder combined with oil does not have a significant effect on the reduction of these elements. The increase in IFT is also observed due to the evaporation of light oil compounds, and IFT increases further due to the higher temperature of the sample containing carbonate rock powder.
Mohsen Seid Mohammadi; Jamshid Moghadasi; Amin Kordestany
Abstract
Wettability alteration is an important method for increasing oil recovery from oil-wet carbonate reservoirs. Chemical agents like surfactants are known as wettability modifiers in carbonate systems. Oil can be recovered from initially oil-wet carbonate reservoirs by wettability alteration from oil-wet ...
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Wettability alteration is an important method for increasing oil recovery from oil-wet carbonate reservoirs. Chemical agents like surfactants are known as wettability modifiers in carbonate systems. Oil can be recovered from initially oil-wet carbonate reservoirs by wettability alteration from oil-wet to water-wet condition with adding dilute surfactant and electrolyte solutions. This paper investigates the effects of brine concentration, surfactant concentration, and the pH of injection water on the wettability alteration of carbonate reservoirs by different class of surfactants. Scanning electron microscopy images verified the formation of surfactant layer surfaces and the adsorption of surfactant molecules on the rock. The results revealed that TX-100, as a nonionic surfactant, and CTAB, as a cationic surfactant, were better wettability modifiers than SDS, as an anionic surfactant, for carbonate rocks. At the concentration of 1 wt.% and higher, the contact angle reduction was approximately unchanged. The results also proved that there was an optimum salinity for the maximum wettability alteration by surfactants. Increasing the pH of aging fluid resulted in better wettability alteration by CTAB, while, in the case of SDS, the wettability alteration was reduced. Acidic conditions had a negligible effect on the wetting behavior of TX-100.
