Patent Number: 6,167,974

Title: Method of underbalanced drilling

Abstract: Apparatus and associated methods are provided which facilitate underbalanced drilling and completion of wells. In a described embodiment of a well control valve, the valve is opened and closed when a drill string is displaced therethrough. A shifting device is carried on a drill bit and deposited in the valve when the drill string enters and opens the valve. The valve is closed and the shifting device is retrieved from the valve when the drill string is tripped out of the well. A packer hydraulic setting tool usable in conjunction with the well control valve in underbalanced completions is also provided.

Inventors: Webb; Alan B. (Fort Worth, TX)

Assignee: Halliburton Energy Services, Inc.

International Classification: E21B 23/00 (20060101); E21B 23/06 (20060101); E21B 34/00 (20060101); E21B 34/14 (20060101); E21B 21/00 (20060101); E21B 034/14 ()

Expiration Date: 01/02/2018