In overbalanced drilling conventional well control is affected by using a hydrostatic pressure greater than the pore pressure. In under balanced drilling this differential is removed and bottom hole pressure is maintained at a value less than the pore pressure. Therefore there is a continuous "well control situation" during the under balance section.

To do this requires some form of rotating control device, drilling chokes, specialised fluids and different operating techniques.

Keywords:
selection, balanced operation, annular pressure drilling, operation, investment, randy smith training solution, drilling, balance drilling, balanced drilling, upstream oil & gas
Subjects:
Drilling Operations, Pressure Management, Drilling Fluids and Materials, Well control
Copyright 2003, IADC/SPE Underbalanced Technology Conference and Exhibition
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