WO2011159983A1
|
|
Continuous circulating sub for drill strings
|
CA2787003A1
|
|
Drill string flow control valve and methods of use
|
US2009211814A1
|
|
Drill string flow control valves and methods
|
EP1957744A1
|
|
Method for varying the density of drilling fluids in deep water oil and gas drilling applications
|
WO2005042911A2
|
|
System for drilling oil and gas wells using oversized drill string to achieve increased annular return velocities
|
CA2544405A1
|
|
System for drilling oil and gas wells using a concentric drill string to deliver a dual density mud
|
CA2519365A1
|
|
System and method for treating drilling mud in oil and gas well drilling applications
|
WO2004044366A2
|
|
Method and apparatus for varying the density of drilling fluids in deep water oil drilling applications
|