The present invention relates to an apparatus and method for isolating a wellbore condition such as formation pressure during a wellbore operation. The invention has particular application in connection with underbalanced drilling. In one arrangement, a formation isolation apparatus is provided that serves as a selectively actuatable plug. The plug in one aspect is selectively set and released by a setting/releasing tool. The setting/releasing tool includes a system for setting the plug in the wellbore, and a system for releasing the plug from the wellbore. The setting/releasing tool is releasably connected to the plug. Thus, after the plug has been set, the setting/releasing tool may be removed from the wellbore. The plug includes a flapper valve that is restrained in its open position by the setting/releasing tool. Removal of the setting/releasing tool from the wellbore allows the flapper valve to close, thereby isolating pressures in the wellbore below the flapper valve. The plug is wireline retrievable. In another aspect, a formation isolation apparatus is provided for use during sidetrack drilling operations. The sealing element is movable from a first released position below the lateral wellbore, to a set position above the lateral wellbore.
A technique to place a completion assembly in a well while maintaining the well in an underbalanced condition includes running a plug on a deployment tool to a desired depth in the well. The technique includes setting the plug in the well; retrieving the deployment tool; and running the completion assembly on a setting tool into the well to engage the plug. The technique includes releasing the plug; running the completion assembly and plug to a desired depth in the well; and setting the completion assembly in the well. The setting tool is retrieved, which includes retrieving the plug.
Methods and apparatus for utilizing a downhole deployment valve (DDV) to isolate a pressure in a portion of a bore are disclosed. The DDV system can include fail safe features such as selectively extendable attenuation members for decreasing a falling object's impact, a normally open back-up valve member for actuation upon failure of a primary valve member, or a locking member to lock a valve member closed and enable disposal of a shock attenuating material on the valve member. Actuation of the DDV system can be electrically operated and can be self contained to operate automatically downhole without requiring control lines to the surface. Additionally, the actuation of the DDV can be based on a pressure supplied to an annulus.
The present generally relates to apparatus and methods for instrumentation associated with a downhole deployment valve or a separate instrumentation sub. In one aspect, a DDV in a casing string is closed in order to isolate an upper section of a wellbore from a lower section. Thereafter, a pressure differential above and below the closed valve is measured by downhole instrumentation to facilitate the opening of the valve. In another aspect, the instrumentation in the DDV includes sensors placed above and below a flapper portion of the valve. The pressure differential is communicated to the surface of the well for use in determining what amount of pressurization is needed in the upper portion to safely and effectively open the valve. Additionally, instrumentation associated with the DDV can include pressure, temperature, seismic, acoustic, and proximity sensors to facilitate the use of not only the DDV but also telemetry tools.
