科研之友
微信
新浪微博
Facebook
分享链接
摘要
The NMR propagator technique allows the measurements of the variance sigma(2) = <(xi - <xi >)(2)> of the displacements as a function of time t when flowing in a porous media. The time dependence of sigma is a very sensitive test of Gaussian behavior compared to the analysis of the shape of the propagators. Superdispersion occurs when sigma(2) alpha t(alpha) with the exponent a larger than 1. In a homogeneous 30-mu m grain pack and 10 < Pe < 35, we observed weak superdispersion in saturated conditions (alpha = 1.17) and gradually strong superdispersion as the water saturation decreases (up to alpha = 1.5) during steady-state oil-water two-phase flow. In saturated conditions, the corresponding longitudinal propagators and breakthrough curves are Gaussian or nearly Gaussian, whereas in two-phase conditions, the longitudinal propagators are nonsymmetric and the breakthrough curves show a tail at long times. DOI: 10.1103/PhysRevE.87.043007
- 出版日期2013-4-12
