The sol-gel transition of aqueous alginate solutions induced by calcium cations has been studied by using dynamic light scattering.A critical relaxation was observed near the gel point,which was characterized by the p...The sol-gel transition of aqueous alginate solutions induced by calcium cations has been studied by using dynamic light scattering.A critical relaxation was observed near the gel point,which was characterized by the power law of the time-intensity correlation function g（2）（t）-1∝t-μ.The comparison of this critical exponent μ with the critical exponent n for mechanical relaxation obtained with dynamic rheology measurements shows μ=2n for the Ca-alginate sol-gel transition.The critical exponent μ was found to be proportional to q2,q is the scattering vector,and the proportional coefficient almost equaled to the correlation length of the critical gel.展开更多
The gel point of crude oil is one of the important parameters for oil and gas field development, oil and gas storage and transportation.The conventional method can only measure the gel point of the crude oil free of g...The gel point of crude oil is one of the important parameters for oil and gas field development, oil and gas storage and transportation.The conventional method can only measure the gel point of the crude oil free of gas under atmospheric pressure.A new method for measuring the crude oil with dissolved gas under high pressure based on a new measurement principle was proposed.A new instrument of gel point measurement for crude oil with dissolved gas under high pressure was designed.The result measured by the new instrument was compared with that measured by the conventional method.The effect of pressure and solution gas-oil ratio on the gel point of crude oil was studied.Experiments showed that the results measured by the new instrument coincided with that by the conventional method for crude oil free of gas under atmospheric pressure.Under the same solution gas-oil ratio, the gel point of crude oil with dissolved gas increased with pressure, the gel point increased by 0.7℃ with 2.0 MPa pressure increment in the experimental conditions.The gel point of crude oil with dissolved gas decreased with solution gas-oil ratio under the same pressure, the gel point decreased by 1.0℃ with 10.0 m3·m-3 solution gas-oil ratio increment in the experimental conditions.The result is of importance to the management of waxy oil production and the design for oil and gas storage and transportation.展开更多
文摘The sol-gel transition of aqueous alginate solutions induced by calcium cations has been studied by using dynamic light scattering.A critical relaxation was observed near the gel point,which was characterized by the power law of the time-intensity correlation function g（2）（t）-1∝t-μ.The comparison of this critical exponent μ with the critical exponent n for mechanical relaxation obtained with dynamic rheology measurements shows μ=2n for the Ca-alginate sol-gel transition.The critical exponent μ was found to be proportional to q2,q is the scattering vector,and the proportional coefficient almost equaled to the correlation length of the critical gel.
文摘The gel point of crude oil is one of the important parameters for oil and gas field development, oil and gas storage and transportation.The conventional method can only measure the gel point of the crude oil free of gas under atmospheric pressure.A new method for measuring the crude oil with dissolved gas under high pressure based on a new measurement principle was proposed.A new instrument of gel point measurement for crude oil with dissolved gas under high pressure was designed.The result measured by the new instrument was compared with that measured by the conventional method.The effect of pressure and solution gas-oil ratio on the gel point of crude oil was studied.Experiments showed that the results measured by the new instrument coincided with that by the conventional method for crude oil free of gas under atmospheric pressure.Under the same solution gas-oil ratio, the gel point of crude oil with dissolved gas increased with pressure, the gel point increased by 0.7℃ with 2.0 MPa pressure increment in the experimental conditions.The gel point of crude oil with dissolved gas decreased with solution gas-oil ratio under the same pressure, the gel point decreased by 1.0℃ with 10.0 m3·m-3 solution gas-oil ratio increment in the experimental conditions.The result is of importance to the management of waxy oil production and the design for oil and gas storage and transportation.
