Water dilution and subsequent disposal of the excessive mud volume into drilling reserve pits were the simplest ways of dealing with inefficient solids control systems.Properties of all drilling muds tested are shown in Table 1. The only drilling mud used for the full-scale test was the non-dispersed spud mud with limited filtration control.Continue reading “Dewatering Process Efficiency and Effects”
The presence of large amounts of drilled solids in a drilling mud usually
spells trouble for the drilling operation. These solids adversely affect the performance characteristics of the mud and can lead to a multitude of costly hole problems.
The overall efficiency of cuttings removal by the solids-control system, Es, can be expressed as:
Es = E1 f 1 +( 1 – E1 )E2 f 2 + ( 1 – E2 )E3 f 3 +( 1 – E3 )E4 f 4 (1)
Weighted muds are the ones that contain weighting materials. These mud systems are usually used for drilling at deeper depths because of increasing formation pressures. The typical composition of weighted clay/water mud is active clay, and inert solids like barite are used for enhancing the mud weight. As mentioned earlier, the mud arriving at the surface from the bottom while drilling is in progress contains active and inactive drilled solids. Hence, the low gravity solids must be removed first, using a screen, because their disintegration reduces the particle size to less than that of barite or in the similar range. This may cause a loss of costly barite if the mud is subjected to solids control. Once the larger particles are removed the mud must be passed through mud cleaner, where the hydrocyclones are used in series with screens. This system works best for muds with density less than 15.0 lbm/gal.