METHOD FOR INITIATING FLUID CIRCULATION USING DUAL DRILL PIPE

摘要

A method for operating a dual drill string disposed in a wellbore, the string having a shutoff valve for at least a fluid return drill string therein proximate a bottom end thereof includes pumping fluid into both the fluid return string and a fluid supply string of the dual drill string. Circulation of fluid in the wellbore is initiated by pumping fluid into the fluid supply string such that the shutoff valve on the fluid return string opens to enable the fluid leaving the wellbore to enter the fluid return string.