DOWNHOLE DEPLOYMENT VALVES

摘要

Methods and apparatus enable reliable and improved isolation between two portions of a bore extending through a casing string disposed in a borehole. A downhole deployment valve (DDV) may provide the isolation utilizing a valve member such as a flapper that is disposed in a housing of the DDV and is designed t o close against a seat within the housing. The DDV includes an operating mechanism f or opening/closing the DDV. In use, pressure in one portion of a well that is i n fluid communication with a well surface may be bled off and open at well surface while maintaining pressure in another portion of the casing string beyond the DDV.