Numerical Study on Mobilization of Oil Slugs in Capillary Model with Level set Approach

Abstract

Numerical investigation on mobilizing oil slugs trapped in an axisymmetric capillary tube saturated with water was conducted. The governing equations for the incompressible two-phase core-annular flow in a capillary model were derived. Numerical solutions for capturing the evolution of interface between oil and water were developed using a level set approach. A projection method was applied to obtain the velocity field of the twophase flow. The existence of a water film between the oil slug and solid tube wall was evident in mobilizing the oil slug, and the water film clearly reduced the external pressure required to mobilize the oil slug. This result matches with the experimental phenomena reported in the literature. New phenomena in oil slug mobilization and motion were also found in the numerical investigations. The results obtained showed the high efficiency of the presented approach and the significance of water film in improving the mobilization of oil slugs.

Comment on the level-set method used in ‘Numerical study on mobilization of oil slugs in capillary model with level set approach’

“…For the discretization in space, a second-order essentially non-oscillatory (ENO) scheme (Shu & Osher, 1988) is employed for all spatial derivatives, except for the discretization of the viscous terms in the Navier-Stokes equation, where the standard central difference scheme is used. This is the same approach as used in Dai and Wang (2014).…”

“…The numerical methods used in Dai and Wang (2014) are now briefly outlined. On the few points where the description in Dai and Wang is not detailed enough for a full reproduction, the assumptions made in this paper about what Dai and Wang used are stated.…”

“…The paper is organized as follows. In the next section, the content of Dai and Wang (2014) is summarized. Section 3 presents a brief review of the computational methods used, then section 4 argues the case that the validation in Dai and Wang , as well as some of the physical interpretations, is based on numerical artifacts.…”

“…The rapid development of computational methods means that much effort is needed to reproduce a result that uses many complicated methods. In this particular case, it is extraordinarily fortunate that it is possible to reproduce and make comments on the results of Dai and Wang (2014), since in-house Fortran code that already has the methods they implemented is available. Dai and Wang (2014) concerns the mobilization of oil slugs in capillaries.…”

“…In this particular case, it is extraordinarily fortunate that it is possible to reproduce and make comments on the results of Dai and Wang (2014), since in-house Fortran code that already has the methods they implemented is available. Dai and Wang (2014) concerns the mobilization of oil slugs in capillaries. The physics of this interesting phenomenon are not discussed here; the reader is referred to Morrow and Mason (2001) for a review of the importance of oil slugs in capillaries to the recovery of crude oil, and CONTACT Åsmund Ervik asmunder@pvv.org to Mumley, Radke, and Williams (1986) for a review of liquid-liquid flows in glass capillaries, which can be used as a model system.…”