Harold S. Bissonnette
Engineering at Royal Oak St, Wichita Falls, TX

4669541, Jun 2, 1987

Oct 4, 1985

6/784401

Harold S. Bissonnette - Wichita Falls TX

Dowell Schlumberger Incorporated - Tulsa OK

E21B 3414

166154

A stage collar for stage cementing a well casing includes a slidable closing sleeve having ports alignable with ports in the stage collar case. These closing sleeve and stage collar ports communicate with an annulus around the well casing when the stage collar is open. A shift sleeve closes the ports during running in and is actuable by simple drill pipe movements to open and reclose the stage collar ports. The shift sleeve is operably coupled to the closing sleeve by a latch ring which locks the closing sleeve closed and cooperated therewith to form a smooth and substantially uniform inner stage collar bore. The drill pipe is operably connected to the stage collar by a screw-in or latch-in shifting tool which cooperates with the stage collar elements to form a fluidtight passage from the drill pipe to the annulus without entering the well casing interior. A dual stage shifting tool is also shown which permits a two-stage cementing operation to be performed with only one run down the hole.