Desander is drilling rig equipment with a set of hydrocyclones that separates sand and silt from the drilling fluid. Desander is installed after shale shaker and degasser but before desilter.
Desander removes the abrasive solids from the drilling fluids which cannot be removed by shakers. Normally the solids diameter for desander to be separated would be 44~74μm, and 15~44μm for desilter.
Desander is the second-level solid control equipment used in drilling fluid solid control system, is the assembly of cyclone desander and shale shaker. Cyclone desander is designed by the principle of particle sedimentation, the drilling fluid enters into inwall of swirler, the thicker particles spiral sinking with the action of centrifugal force and gravity, discharged from bottom exit, and separated by shale shaker, the other liquid spirals along the swirler, enters into the third-level separation equipment – desilter from overflow port to dispose further.
Desander has no moving parts. The larger internal diameter (ID) of the desander is, the greater the amount of fluid it is able to process and the larger the size of the solids removed. Desander (10 in.cone) are able to remove roughly 50 percent of those solids within the 40-50 micron range at a flow rate of 500 gallons per min (gal/min), while desilter (4 in. Cone) are able to remove approximately 50 percent of those solids within the 15-20 micron range at a flow rate of 60 gal/min. Micro fine separators are able to remove around 50 percent of those solids within the 10-15 micron range at a flow rate of 15 gal/min.
When choosing the desander, the maximum displacement of the drill pump must be considered to achieve the reasonable matching. No matter the desander or the desilter, it must be ensured that the maximum displacement of the drilling fluid in the drilling process can be all disposed.