To fulfill these tasks effectively, the mud contains carefully chosen additives to control its chemical and rheological properties.
When returning to the surface through the much roomier annulus it is under less shear stress and becomes more viscous, and hence better able to carry the rock cuttings.
This is critical in a drilling operation to avoid a kick and ultimately a blowout from uncontrolled production of formation fluids.
In many areas oil-based muds are being phased out, as they are less environmentally friendly, although in some formations they are necessary because of chemical compatibility issues.
After several years as, for example, a drilling assistant, one can obtain the role by demonstrating sufficient expertise in math, physics, geology, chemistry, IT, and related fields.
[7] Before the mid-1940s, the driller dealt with drilling mud; but specialization occurred with the increasing complexity and overlapped more with the geologist.
He or she must also keep an eye on the equipment which is used to pump the mud and to remove particles, and be prepared if the geologists' predictions are not entirely correct, or if other problems arise.
This is referred to as a formation "kick" and can lead to a potentially deadly blowout if the invading fluid reaches the surface uncontrolled.
ANA Industries Limited is also the largest independent drilling fluids company presently in West Africa