Wellhead Desanders

The objective of the Wellhead Desander is to remove sand from the multi-phase well-stream, either upstream or downstream of the well-head choke depending on whether choke erosion is a problem; or the volume of gas. Operating at the higher pressures reduces the physical size of the unit due to the reduced volume of the gas at the higher pressure.

Solids arising in well-stream fluids are normally in the 50 to 500 micron in size range, and are found in varying amounts in different wells. A normal range would be from 5 to 120 ppm for a producing well, and in some cases over 5% by weight in well clean-up operations.

All of the well-stream fluids pass through the Wellhead Desander into the downstream separation process. The sand that is removed falls down into a collection chamber, called the Accumulator Vessel, beneath the Desander for disposal. The Accumulator Vessel is periodically isolated from the Wellhead Desander and de-pressured, and the sand flushed out to the cleaning / disposal system using plant or produced water. Whilst the Accumulator Vessel is being purged, the Wellhead Desander remains on-line with sufficient hold-up volume to collect sand separated whilst the Accumulator Vessel is off line.

The Wellhead Desander requires no control system, unless the Accumulator Vessel purge is required to be automatic, which can be easily done. Often the Accumulator Vessel purge is carried out manually. The simplicity of the cyclone design means that systems can be provided cost effectively for high design pressures, e.g. well shut-in. The Wellhead Desander itself comprises a single cyclone insert housed inside a vessel designed to the appropriate pressure of up to 15,000 psig.

eProcess Wellhead Desander technology has proven a valuable tool both by oil producers as well as oil service companies. Generally the equipment is provided as a permanent installation on operating systems, or as a portable skid for service company work.