Primary cementing of vertical wells: displacement and dispersion effects in narrow eccentric annuli

Laminar miscible displacement flows in narrow, vertical, eccentric annuli show a wide range of interesting physical phenomena, e.g. static layers and channels, dispersive spikes/fronts various instabilities. These are relevance to the primary cementing wells, where gas leakage greenhouse emissions can result from ineffective cementing. The current popular way model this process is via Hele-Shaw approach, reducing Navier–Stokes equations scaling arguments then averaging across annular gap: two-dimensional (2-D) gap averaged (2DGA) model. This leads reduced that computationally efficient represents some important features flows, but also deficient capturing effects dispersion. While three-dimensional (3-D) simulations able capture dispersion most other they suffer excessive computational times due extreme aspect ratios geometries non-Newtonian properties fluids. Here we extend 2DGA approach by modelling high Péclet number limit duct take into account leading-order Our modified well approximate observed gap-averaging results 3-D computations, including geometric eccentricity marked improvement over while keeping advantages 2-D