Managed pressure drilling system and method of use

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.

A method for managed pressure drilling, the method comprising:

• providing a managed pressure drilling system, the system comprising:
• a rotating sealing device;
• and
• a drill string comprising an upper drill string section and 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 comprises a tubular pipe body with connectors at either end thereof;
• wherein the connectors and the tubular pipe body of each drill pipe member of the upper drill string section have substantially the same outer diameter;
• and
• wherein the outer diameter of the connectors of the drill pipe members of the lower drill string section is larger than the tubular pipe body outer diameter of drill pipe members of the lower drill string;
• lowering the drill string into a tubular connected to a well;
• forming a fluid seal between at least one section of the upper drill string section and a tubular in the well;
• passing at least one part of the drill string through the rotating sealing device;
• and
• drilling the wellbore.

A method for drilling a well, comprising:

• providing a drilling system, the system comprising:
• a rotating sealing device;
• and
• a plurality of drill pipe members comprising first drill pipe members and second drill pipe members, wherein each drill pipe member comprises a tubular pipe body with connector joints at either end thereof;
• wherein first drill pipe members have connector joint outer diameters which are larger than the outer diameter of the tubular pipe body;
• wherein second drill pipe members have connector joint outer diameters which are substantially the same as the outer diameter of the tubular pipe body;
• wherein the first drill pipe members are configured to be connected to form a first drill string section and the second drill pipe members are configured to be connected to form a second drill string section;
• drilling a first section of the well using the first drill string section comprising a plurality of first drill pipe members;
• connecting second drill pipe members to the first drill string section;
• forming a fluid seal between a tubular connected in the well and an outer surface of at least part of a second drill pipe member in the second drill string section;
• passing at least part of the second drill string through the rotating sealing device;
• and
• drilling a second section of the well at a pre-determined fluid annular pressure.