Solids control is a technique used in drilling rig to separate the solids in the drilling fluids that are crushed by the drill bits and carried out of the well surface. Normally solids control system is consisted of five stages, including mud tank, shale shaker, vacuum degasser, desander, desilter, centrifuge. Shale shaker is used to separate the big solids with diameter above 75μm, and 45~74μm for desander, and 15~44μm for desilter. Sometimes desander & desilter are combined as mud cleaner. When air enters into the drilling fluids, vacuum degasser is used to separate the air. If no air is found in the mud, the degasser will work as a big agitator. All these equipment are mounted on the top of the mud tank. After separating the solids, the clean mud will be pumped into the borehole again.

It is necessary to carry out regular efficiency analysis of solids control system in drilling site in order to improve drilling fluids properties and better manage the cost. Generally speaking, the aggregate drilling fluids consumption in a well counts 10 to 20 times the volume of a borehole. That means 90% of the expenses are poured into volume and property maintenance of the additionally concocted 90% drilling fluids. However, it can give birth to remarkable economic benefits if solids control equipment is promptly adjusted to remove more “harmful solid phase”.
 

The efficiency analyses conducted on different equipment show that, theoretically speaking, all of them should have been taken away, but in fact only 80-85% or even lower amount of them have been removed and 90% would have been the best. It is also shown that, by a deeper study into separation capability of various oilfield solids control equipment and size distribution in such useful solid phase as barite and harmful solid phase ( low-density particles ), desander and desilter are not ideal choices to treat barite-weighted drilling fluids, but the decanter centrifuge can decrease the low solid phase gradually accumulated in any type of drilling fluids. “Communique on Drilling Fluids Treatment Equipment” well elaborates the standard application methods and analysis approaches of various solids control equipment, for example. drilling fluids shale shaker ought to be analyzed in terms of its solids removal rate, cuttings removal rate and drilling fluids loss ratio; desander, desilter and drilling fluids decanter centrifuge ought to be analyzed in terms of solids removal percentage, low-density solid phase discharge velocity and barite discharge speed; the drilling fluids decanter centrifuge also need to be calculated on its barite recovery percentage, etc.

Besides, another formula can also work on the calculation of solids control efficiency, such as, if the figures like, dilution volume per unit time, the formation volume and the max. cuttings content got from solid phase analysis are given, we can have the efficiency rate of solids control equipment.

KOSUN is a professional manufacturer for the oil & gas drilling mud solids control system, manufacturing not only vacuum degasser, but also electrical ignition device, and also shale shaker screen, mud cleaner, centrifugal pump, vacuum degasser, shear pump, mud agitator, mud gun, jet mud mixer, desilter, desander, decanter centrifuge, mud tank, submersible slurry pump, etc. KOSUN has been serving the oil & gas industry for 20 years since its establishment in 1992, and has obtained good experience on equipment manufacturing & oilfield service.