Effect of Asphaltenes on Wettability of Gas and Oil Saturated Reservoir Rocks

Doklady Earth Sciences - The wettability by asphaltenes of siliciclastic and carbonate drill–cores from oil and gas condensate fields extracted with n-hexane and chloroform was studied. The...     

Physicochemical peculiarities of absorbed oil in core samples of gas condensate deposit

The problem of the composition of absorption hydrocarbons and liquid condensate arises in the study of gas condensate reservoirs. From the examples of the gas condensate part of the Karachaganak, Astrakhan, and Yamburg deposits, it is shown that absorption hydrocarbons (absorption oil) contain polar components with S and O atoms in molecules. The differences in the physicochemical properties of absorbed oil and precipitated liquid condensate are revealed, as are the regularities in the composition and properties of the absorbed oil and condensate. The criteria for division of absorption oil and liquid condensate are given.     

The effect of the pore space microstructure on hydrophobization of oil and gas reservoirs

The results of theoretical and experimental studies of the effect of the microstructure of the pore space on the hydrophobization of oil and gas reservoirs are presented. A possible mechanism of formation of the microstructured wettability is described, which demonstrates that hydrophobization of the inner pore space in mixed wettability can be associated either with large or small pore sizes. It was proven experimentally that the process of hydrocarbon adsorption depended on the shape, size, and distribution of pores, the mineralogical composition (particle composition and size, presence of clay), as well as on the time of contact of hydrocarbons with the inner pore surface. The concept of the hydrophilic nature of rock prior to the migration of oil into it can be considered as accurate. However, as was shown in the experiments, oil could be present in the small pores (up to 10 μm), which was especially significant for the carbonate reservoirs.     

Influence of the Component Composition of Adsorbed Oil on the Microstructural Wettability of Hydrocarbon Reservoirs

Doklady Earth Sciences - The physicochemical mechanism of the development of microstructural wettability in oil and gas reservoirs is experimentally justified. It is shown that this mechanism is...