1.While underbalance drilling spreads greatly, rotating blowout preventer, as a kind of high technical product, is the crucial equipment to control well pressure.
2.Biolithite loss zone is a kind of special reservoirs where rock structure is frailish and lot of pore spaces and gas exist, while severe circulation loss and well blowout and well kick occur.
3.The purpose of the bulkhead is threefold: to seal the forward end of the motor, to retain the pyrogen igniter, and to act as a blowout plug in case of motor overpressurization (discussed earlier).