Classification and working characteristics of Trenchless HDD Desander and Desilter
The separation capacity of the cyclone of Trenchless HDD Desander and Desilter is related to the nominal diameter of the cyclone. The smaller the nominal diameter, the smaller the particles that can be separated. The nominal diameter of the cyclone of Trenchless HDD Desander and Desilter refers to the diameter of the part of the cylinder on the centrifugal cone. According to different nominal diameters, cyclones are divided into three categories: Trenchless HDD Desander and Desilter and micro cyclones.
Desander is used to separate drill cuttings of 40～70μm and barite of 30～50μm. When the drilling fluid vibrating screen cannot be equipped with API140 mesh screen (100μm) or a finer screen, the de-sander can only be used to process unweighted drilling fluid. They were originally used to remove high solids during rapid drilling of surface wells. In water-based drilling fluids, the separation point of the desander is 40-70μm and the density is 1.6g/cm3. Sand and larger particles are removed by the desander after passing through the drilling fluid vibrating screen.
The de-sander is directly installed downstream of the drilling fluid shaker and the vacuum deaerator, and is directly sucked in from the upstream tank, which is generally the discharge tank of the vacuum deaerator. The discharge from the desander enters the downstream tank directly. The suction and discharge tanks are balanced by a valve at the bottom of each tank.
Desanders are used uninterruptedly when drilling surface wells. After starting to drill down, a manifold can be installed to handle all the usage of surface tanks. After barite and polymer are added to the drilling fluid, the desander is generally no longer used, because the desander will remove most of them.
The cone of the desilter has a variety of sizes, the common one is 50-150mm, which can separate drill cuttings of 12-40μm and barite particles of 8-25μm. The separation particle size of the microcyclone with a diameter equal to 50mm can reach 5-10μm. The desilter is installed downstream of the drilling fluid vibrating screen, grit tank, vacuum degasser and desilter. The cone of the desilter is only different in size from the desilter, and the working principle is exactly the same. A separate sand pump should be used to feed the desilter. Try not to use the same sand pump to supply multiple materials at the same time. Parallel devices.
The desilter can realize the separation of drill cuttings as small as 12μm . It is an important equipment to reduce the average particle size and the concentration of drill cuttings. The slurry inlet of the desilter can also be installed directly in the upstream tank, usually the discharge tank of the desilter. The suction and discharge tanks of the desilter pass through one or more valves. The general experience recommends the size of the valve as follows:
Diameter Φ=Qmax/100 (mm)
Among them, Qmax is the allowable processing capacity rather than the maximum displacement during drilling, and the unit is L/min. The permitted processing volume should be 1.25 times the minimum volume, and Trenchless HDD Desander and Desilter is generally not used to process oil-based drilling fluids.