Petroleum Engineering
Bardiya Yazdani; Amir Hossein Saeedi Dehaghani
Abstract
This research purpose is 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 have been investigated by microwave ...
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This research purpose is 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 have been investigated by microwave radiation. Viscosity and temperature changes of two samples have been measured. IP143 and elemental analysis (Carbon, Hydrogen, Nitrogen, and Sulfur) were used to extract and identify the composition changes of asphaltene, respectively. Based on the viscosity and temperature changes, it was found that for both samples at the beginning of microwave radiation there was a decrease in viscosity as a result of heavy hydrocarbon particles cracking, such as asphaltene, and converting them into lighter ones. By continuing the radiation and temperature increase, light compounds started to evaporate; finally, the increase in viscosity was observed. The evaporation process in the sample containing carbonate powder started earlier than the sand powder. From elemental analysis, it was concluded that the sulfur and nitrogen in asphaltene have decreased almost the same for both samples, and this decrease is more evident for sulfur, so the rock powder combined with oil did not have a significant effect on the reduction of these elements. The increase in IFT was also observed due to the evaporation of light oil compounds, and due to the higher temperature of the sample containing carbonate rock powder, more IFT increases have been observed.
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.
