Efficient solids control improves drilling efficiencies by reducing dilution rates and maintaining mud properties. This helps keep penetration rates and reduces the need for additives. A decanting centrifuge processes the mud pond to separate sand and silt. It also processes LG solids to discard them or, on unweighted muds, to return them as liquid colloidal material back into the active system.
Reduced Dilution Rates
Modern drilling techniques continuously generate colloidal and ultrafine solids through natural degradation faster than they can be removed by solids control equipment. The result is that mud systems will degrade, increasing the plastic viscosity and negatively impacting the performance of the rig, formation and drilling process. Most solids control equipment is designed to remove particles based on size and specific gravity, including shale shakers, desander, desilters, bowl centrifuges, and hydro cyclones. A decanter centrifuge targets these particles with a higher G-force and enables the removal of these high-specific gravity solids at a much higher rate. This significantly reduces dilution rates and allows the centrifuge to achieve closer to its optimum efficiency level. This translates into cost savings from reduced waste disposal volumes, reduced dilution rates and less use of additives.
Reduced Chemical Additives
Modern drilling practices are generating colloidal solids at a rate that rapidly degrades them. This process creates a constant stream of degradation that must be diluted away or chemically destabilized by adding expensive additives.
Using solids control centrifuges allows for separating solid material from one or more liquids in a continuous, two-phase dewatering operation. The device comprises a conical, horizontal steel bowl rotating at high speed with a screw-shaped conveyor inside. The centrifugal force causes the slurry to separate into two distinct streams: the overflow (a.k.a., center) and the cleaned slurry (“centrifuge overflow”). Many current decanter centrifuge applications for mud systems are counterproductive. One common misuse of the equipment involves running dual centrifuges in series. The first centrifuge recovers barite from the overflow and sends it back to the mud system, while the second centrifuge discards low-gravity solids and returns only a clean slurry to the mud system.
Reduced Downhole Issues
Using a decanter centrifuge for solids control allows drilling companies to reduce waste disposal costs, minimize the use of chemical additives and save time and money on cleanup. This solution is particularly beneficial for projects in soil conditions where mud disposal is either impossible or costly. The first step in a solids control system is the shale shaker which removes a portion of the solids from the drilling fluid that is too large to pass through the holes of the screen. This first removal stage is necessary for the downstream hydro cyclones and decanter centrifuge to be overloaded beyond their design capacities. Using a complete solids control system allows drilling companies to improve the quality of their drilling fluid, reduce mud make-up dilution rates and extend the life of the liquid. This ultimately increases penetration rates, enables better cake wall stability and reduces accelerated wear on drill bits and mud pumps. The resulting improved mud performance helps to improve rig efficiency and productivity.
