Method for controlling entry of a drillstem into a wellbore to minimize surge pressure

摘要: A well drilling system for with gaseous fluid, particularly natural gas, in a closed circulation path including an enclosure or bell nipple mounted on wellhead between the wellbore and rotary control head drillstem. The redirects flow of cuttings laden fluid being circulated out includes plurality fire extinguishing injection nozzles arranged to inhibit extinguish within head. Drill are separated from pressure vessel which separator baffles drill port valve arrangement dumping samples substantial quantities collected during operation system. may be used conjunction operations using conventional liquid fluids liquid-solids separation equipment. Methods monitoring surges minimize deviation predetermined condition included rate pressures flowing into controlling insertion drillstem surges.