In the drilling fluid circulation system, the desander and desilter are both composed of a set of hydrocyclones and a small ultra-fine mesh shale shaker that processes the underflow of the cyclone and recovers the drilling fluid. Desander is used to remove 44-74μm solid phase particles, and desilter is used to remove 15-44μm solid phase particles. The particle size in the cyclone is not only related to the structure size of the cyclone, but also related to the drilling fluid concentration, density and fluid inlet pressure.
Due to the drilling fluid requirements, the desander and desilter must be composed of several cyclones. In order to ensure the normal operation of the cyclone, the liquid inlet pressure must be maintained within the range of 0.25-0.35MPa. Because the desilter has many cones and long pipelines, the liquid inlet pressure should take a larger value; because the desander has fewer cyclones and short pipelines, the liquid inlet pressure should take a smaller value. The size of the liquid inlet pressure mainly depends on whether the matching of the sand pump is reasonable, so the selection of the sand pump is very important.
At the same time, how should we choose a suitable desander and desilter so that it can exert its maximum effect in the whole drilling fluid solids control system? First of all, it is necessary to refer to the maximum displacement of the drilling pump in order to achieve a reasonable matching. There is no strict limit on the use time of these two types of equipment. Generally, when drilling shallow formations and soft formations, the content of large-particle cuttings in the drilling fluid is high, and the two must be used at the same time; when drilling formations and hard formations, if using fine mesh shale shaker can directly use the desilter to treat the drilling fluid, which has little effect on the purification quality of the drilling fluid and is very economical.
When using the desander and desilter, you also need to pay attention to the skills, as follows:
Before use: Check the fixation, oil quantity, sealing packing and transmission part of the sand pump, the connection of each pipeline, water eye, pressure gauge
When starting: hook the start switch twice.
After startup: check the pipeline, pressure and cyclone, drain the drilling fluid when it is stopped.
Following the above rules will be of great benefit to both the handling capacity of the desander and the desilter, as well as their service life.