Method and apparatus for opening downhole flapper valves

Abstract

The disclosure provides a method and apparatus for effecting the noncontact opening of a flapper valve disposed downhole in a well. Such flapper valves may be located below a seal bore in a downhole tool such as a packer. An annular housing having external seals engagable with the seal bore can be positioned within the downhole tool. Fluid circulation through the annular housing during insertion is permitted by a ball valve mounted in its axial bore and engagable with a downwardly facing sealing surface. Upon engagement of the seals on the annular housing with the seal bore, the housing is converted into a piston and the amount of force exerted on trapped fluid between the annular housing and the flapper valve may be adjusted by adding weight from the tubing string. Fluid pressure above the flapper valve is increased to a level exceeding the closing forces on the flapper valve and the valve opens without any mechanical contact being made therewith. Subsequently the annular housing may be passed downwardly through the flapper valve and is expanded into the bottom of the well by dropping a ball into engagement with an upwardly facing sealing surface on the annular housing and increasing the fluid pressure above the ball to a level sufficient to shear the shearable connection between the annular housing and the production tool.