Some amphoteric surfactants (N-Decyl-N-benzyl-N-methylglycine(AB) and N-Dodecyl-N-benzyl-N-methylglycine(CD) were prepared in the laboratory. The physicochemical chemical characteristics were investigated. The adsorpt...Some amphoteric surfactants (N-Decyl-N-benzyl-N-methylglycine(AB) and N-Dodecyl-N-benzyl-N-methylglycine(CD) were prepared in the laboratory. The physicochemical chemical characteristics were investigated. The adsorption behavior of these surfactants at oil/air interface was investigated by measuring the surface tension and interfacial tension as function of concentration. Surface properties, in particular the critical micelle concentration (CMC), the maximum surface excess (ΓCMC) and the minimum surface area (AMIN) were measured. It is found that the surface and thermodynamic properties of the prepared surfactants depend on their hydrocarbon chain length. Also it is found that there is a good relation between surface properties of the additive and their efficiency in depressing the pour point. The mechanism of the depressants action has been suggested according the adsorption of each additive. Adsorption of the additive on the surface of the wax particles inhibits their growth and alters the crystal habits through micelle core. As the results the surface and thermodynamic parameters confirm the suggested mechanism and the decreasing of pour point. This is resulted in a multilayer, more isotropic wax crystal, and thus only a fixed amount of wax separates at any given temperatures. The results were discussed in terms of adsorption isotherm.展开更多
In a shale gas and oil reservoir,hydrocarbon fluids are stored in organic nanopores with sizes on the order of~1-100 nm.The adsorption,selectivity,and phase behavior of hydrocarbons in the nanopores are crucial for es...In a shale gas and oil reservoir,hydrocarbon fluids are stored in organic nanopores with sizes on the order of~1-100 nm.The adsorption,selectivity,and phase behavior of hydrocarbons in the nanopores are crucial for estimating the gas-in-place and predicting the productivity.In this study,to understand the characteristics of the phase behavior of multicomponent hydrocarbon systems in shale reservoirs,the phase behavior of a CH_(4)/n-C_(4)H_(10)binary mixture in graphite nanopores was investigated by Grand Ca-nonical Monte Carlo(GCMC)molecular simulation.The method for determining the dew-point pressure and bubble-point pressure in the nanopores was explored.The condensation phenomenon was observed owing to the difference in the adsorption selectivities of the hydrocarbon molecules on the nanopore surfaces,and hence the dew-point pressure(and bubble-point pressure)of hydrocarbon mixtures in the nanopores significantly shifted.The GCMC simulations reproduced both the higher and lower bubble-point pressures in nanopores in previous studies.This work highlights the crucial role of the selec-tivity in the phase behavior of hydrocarbons in nanopores.展开更多
文摘Some amphoteric surfactants (N-Decyl-N-benzyl-N-methylglycine(AB) and N-Dodecyl-N-benzyl-N-methylglycine(CD) were prepared in the laboratory. The physicochemical chemical characteristics were investigated. The adsorption behavior of these surfactants at oil/air interface was investigated by measuring the surface tension and interfacial tension as function of concentration. Surface properties, in particular the critical micelle concentration (CMC), the maximum surface excess (ΓCMC) and the minimum surface area (AMIN) were measured. It is found that the surface and thermodynamic properties of the prepared surfactants depend on their hydrocarbon chain length. Also it is found that there is a good relation between surface properties of the additive and their efficiency in depressing the pour point. The mechanism of the depressants action has been suggested according the adsorption of each additive. Adsorption of the additive on the surface of the wax particles inhibits their growth and alters the crystal habits through micelle core. As the results the surface and thermodynamic parameters confirm the suggested mechanism and the decreasing of pour point. This is resulted in a multilayer, more isotropic wax crystal, and thus only a fixed amount of wax separates at any given temperatures. The results were discussed in terms of adsorption isotherm.
基金the Promotion of Science(JSPS)for a Grant-in-Aid for Scientific Research A(No.24246148)a Grant-in-Aid for Scientific Research C(No.17K06988).
文摘In a shale gas and oil reservoir,hydrocarbon fluids are stored in organic nanopores with sizes on the order of~1-100 nm.The adsorption,selectivity,and phase behavior of hydrocarbons in the nanopores are crucial for estimating the gas-in-place and predicting the productivity.In this study,to understand the characteristics of the phase behavior of multicomponent hydrocarbon systems in shale reservoirs,the phase behavior of a CH_(4)/n-C_(4)H_(10)binary mixture in graphite nanopores was investigated by Grand Ca-nonical Monte Carlo(GCMC)molecular simulation.The method for determining the dew-point pressure and bubble-point pressure in the nanopores was explored.The condensation phenomenon was observed owing to the difference in the adsorption selectivities of the hydrocarbon molecules on the nanopore surfaces,and hence the dew-point pressure(and bubble-point pressure)of hydrocarbon mixtures in the nanopores significantly shifted.The GCMC simulations reproduced both the higher and lower bubble-point pressures in nanopores in previous studies.This work highlights the crucial role of the selec-tivity in the phase behavior of hydrocarbons in nanopores.
