Patent ID: 11952840
Assignee: DEEP BLUE OIL & GAS LIMITED
Field: Civil engineering (Other fields)
Classification: CPC E | IPC E

Claim 11:
12. A drill string assembly for managed pressure drilling comprising:
an upper drill string section connectable to a lower drill string section, wherein the upper and lower drill string sections each comprise a plurality of drill pipe members, wherein each drill pipe member has:
a first tool joint having a first tool joint outer diameter;
a second tool joint having a second tool joint outer diameter; and
a tubular body between the first and second tool joints having a tubular body outer diameter;

wherein the outer diameters of the first tool joint, the second tool joint and the tubular body of the drill pipe members of the upper drill string section are substantially equal; and
wherein the outer diameters of the first tool joint and/or the second tool joint of the drill pipe members of the lower drill string section is larger than the tubular body outer diameter of the drill pipe member of the lower drill string section.