The Challenge Of Well Control In Under Balance Drilling And The Role Of Training In Meeting It

Abstract 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.