With a model of foam wellbore flow and a model of foam seepage flow,a mathematical model of foam plug removal is given.The model is solved with numerical method.Distributions of foam pressure,foam quality,foam density along wellbore and wellhead and bottom pressure are discussed.Furthermore,variation of bottom hole differential pressure is given as wellhead back pressure is fixed.It shows that as foam pressure and density increases,foam quality decreases with increase of well depth and bottom hole differential pressure declines.

Level set and volume of fluid(VOF) methods for incompressible two-phase micro flows considering wall adhesion are presented. In the level set method, based on staggered MAC grid, a second-order projection method is carried out to solve 2D Navier-Stokes(N-S) equations and level set function. In the VOF method, the volume fraction of each phase in each computational cell is employed. Variables and properties of flow are computed to represent volume-averaged values. The interface between fluids is traced with solution of a continuity equation for volume fractions. Computational results are shown and compared with experimental results.