I need some assistance with these assignment. what are the challenges posed for underbalanced drilling operation Thank you in advance for the help!

I need some assistance with these assignment. what are the challenges posed for underbalanced drilling operation Thank you in advance for the help! If the operations are carried out scientifically and as per designed guidelines, most of the shortcomings of overbalanced drilling operations such as mud formation, mixing of circulating fluids, and other impurities getting trapped in the drilled oil stand to be eliminated. More research is taking place in this field to make the underbalanced drilling operation more robust since a substandard underbalanced drilling operation has the potential to cause more damage than a poorly executed overbalanced drilling operation.&nbsp.

The main intent of looking for other forms of drilling is to address the issues and concerns that overbalanced drilling brings about. Since most formations are in an overbalanced state, these are usually drilled using water-based high-density fluids. Such a situation creates an overbalanced pressure, which is a sum of the hydrostatic pressure of the liquid column and pressure transmitted by the pump to the circulating fluid. (Thomas F.B and Bennion D.B, 1994) This pressure exceeds the inherent pressure in the rock formation thereby resulting in the upward movement of oil through the drilled crevice. Some of the anomalies which underbalanced drilling seeks to avoid are the mixing of mud with oil thereby forming sludge emulsions. The incompatibility between the drilling fluid and soil formations like smectitic clay or kaolinite clay has the tendency of swelling the rock formation thereby reducing its permeability characteristics. (Thomas F.B and Bennion D.B, 1994) Artificial agents in the drilling fluid or drill bits that might get entrapped in the fluid have the tendency of reducing permeability. Another concern is the entrapment of the mixed oil-water phase near the wellbore that reduces oil production significantly. Sometimes chemical additives are mixed in the drilling fluid to generate more impact. This however has the tendency of getting adsorbed into the system thereby reducing oil flow. (Thomas F.B and Bennion D.B, 1994)&nbsp.