Flow of noncolloidal slurries in pipelines

Abstract

A multiphase model for the flow of dense, noncolloidal, settling slurries through horizontal pipelines, and an associated Galerkin-finite element numerical scheme to carry out computer simulations based on the model, were developed. The principal elements of the model are: equations for estimation of the velocity distributions for each component: and those for the concentration distributions. In the former, which are derived from the local volume-averaged, time-smoothed conservation of mass and momentum equations, the total stress is comprised of components to account for interparticle and particle-boundary as well as viscous and turbulent interactions. The governing equations for the concentration distributions are derived similarly from the convective diffusion equation, with the eddy diffusivity modified to account for the presence of the solid particles. Numerical simulations and detailed comparisons with experiment for the flow of gypsum, coal, crushed glass, sand and gravel, covering particle sizes from 38.3 pm to 13,000 pm, and pipe diameters from 4 cm to 49.5 cm, were carried out. The agreement between model prediction and experiment is excellent. Previous Work and Background Datalowed one of these three major approaches:Studies concerned with solid-liquid mixture flows have fol-1) The empirical approach 2) The rheologically-based continuum approach 3) The multiphase flow modeling approach The empirical correlation approach seems to have received the most attention, certainly early on, almost surely as a concession to the mathematical complexity of slurry flows. Because of its long history, a large body of empirical studies dealing with slurry transport has accumulated. Correlations for prediction of

Cuttings-Transport Problems and Solutions in Coiled-Tubing Drilling

“…This is the optimum cuttingstransport method if an adequate flow rate can be achieved in all areas of the hole. Although models of solids transport by liquids in turbulent flow have existed in the slurry-transport industry for more than 30 years (see, for example, Hsu et al 16 ), only recently have these models been applied to solids transport in oil wells. [17][18][19] In a model for CT sand-fill cleanouts, Walton 18 predicted the conditions under which solids beds are formed and calculated the minimum flow rate for complete suspension.…”

Settling and rheology of suspensions of narrow‐sized coal particles

“…For pipeline flow of such coarse, dense slurries we have developed a hydrodynamic, multiphase flow model based on the application of conservation of mass and momentum to the individual solid components and to the continuous phase, and embodying liquid-particle, particle-particle and particleboundary interactions (Hsu et al, 1989). It works very well; calculated results using the model and experimental data on pressure gradient as well as on detailed concentration and velocity profiles for the flows of gypsum, coal, crushed glass, sand and gravel slurries, covering a solid particle size range from 38.3 pm to 13,000 prn, and pipe diameters from 4.0 cm to 49.5 cm were found to be in excellent agreement.…”

Improving Post-Stimulation Coiled Tubing Drillout

“…The determination of the critical flow rate at various well inclinations has been the focus of much previous research (Wilson, 1986;Hsu et al, 1989;Ford et al, 1990;Shah and Lord, 1991;Martins and Santana, 1992;Luo and Chambers, 1992;1993;Clark and Bickham, 1994;Walton, 1995;Zou et al, 2000;Ramadan et al, 2003). However, estimating critical rate or velocity in a dynamic heterogeneous horizontal slurry flow can be very difficult due to the simultaneous effects of pipe geometry, eccentricity, hole inclination, flow regime, fluid properties, and rheology.…”