Solid-liquid flow through a wellhead choke valve

Wellhead choke valves are often subjected to the flow of solid-liquid mixtures due to sand production in oil extraction processes. Generally, the mixture is very dilute, and the main concern of engineers is the extensive wear arising from the continuous impacts between the particles and the internal parts of the valve. However, specific heavy oil extraction processes, such as the CHOPS technique, involve the production of a large amount of sand in the flow during the first months of life of the well. Many problems may arise from these high solid loadings, such as the change of regulation and dissipation characteristics of the device, and the risk of occlusion due to sand accumulation. In the present work the flow of sand-water mixtures through a choke valve is investigated by means of a two-fluid model which has already proved reliable for simpler flows. Starting from the single-phase flow case, validated with respect to our own experimental data, the effect of the presence of sand is studied, focusing on the influence of solids concentration (5 to 20%) and particle size (90 to 200 ??m) on the dissipation characteristics of the device. Moreover, the distribution of the solids concentration is investigated to understand the behavior of the mixture and identify the most critical areas within the device.