Other than the drill floor itself, the solids control system requires more attention than any other single rig system whether onshore or offshore. For that reason, it is most important that the solids control system is designed to be as efficient and as maintenance free as possible. This section will discuss that pan of the mud system extending from the bell nipple (or diverter housing outlet) to the mud pump suction piping.
Degassers are necessary to remove entrained gas bubbles from the mud. Gas-cut mud will impair the performance of centrifugal pumps. Since all solids removal equipment beyond the shakers requires a pump, the gas must be removed before it reaches these devices. If left unchecked and pumped downhole, the entrained gas will reduce mud density, which will, in turn, reduce the hydrostatic head in the wellbore.
The drilling fluid circulating system is like a close loop electric circuit through which drilling fluid (i.e. mud) can travel from surface to all the way down hole and back to its initial point (i.e. mud pit).