Abstract: A lateral wellbore junction is formed by methods and apparatus described herein. In one described embodiment, an apparatus includes a section of casing and a sleeve axially reciprocably disposed relative to an opening formed through a sidewall of the casing. In one described method, the casing section is positioned within a parent wellbore, the sleeve is shifted to provide access through the opening, and a lateral wellbore is drilled by passing cutting tools through the opening.

Abstract: An improved diaphragm assembly for use in sealing annular members of marine structures comprising a diaphragm, a pair of flat annular plates and a rip-out assembly.

Abstract: An improved reusable plug for sealing hollow cylindrical members, in particular, the jacket legs, pile sleeves, pilings, conductor pipes, or other similar members of offshore structures, the improved reusable plug comprising a packer mandrel assembly, packer member, packer setting assembly, dog locking sleeve assembly, pressure equalization plug assembly, and overshot retrieving assembly.

Abstract: A differential fill valve assembly for application in float collars or shoes in well casing. The valve assembly comprises a back pressure flapper valve disposed within a substantially tubular upper housing, and a lower housing containing an activating sleeve slidably disposed therein above a double flapper valve assembly. The activating sleeve initially extends into the upper housing to a sufficient extent to maintain the flapper valve in an open position; the activating sleeve is maintained in this position through use of shear pins, by which it is secured to the lower housing. The double flapper valve comprises a first flapper responsive to pressure below the valve assembly, and a second flapper responsive to force applied from above.

Abstract: A combination cementing shoe and basket, comprising a substantially tubular mandrel having a cement basket disposed thereabout, the cement basket being maintained in a collapsed mode by an annular overshot at the bottom of a coupling at the top of the mandrel. A flapper valve assembly is located within the mandrel, being maintained in an open mode by the presence of a fillup tube disposed in the valve orifice. The bottom of the fillup tube is secured to a slidable ball seat located below the flapper valve assembly. The ball seat is initially secured in place by attachment through a plurality of shear rods to a tubular activating sleeve disposed around the mandrel and under the cement basket, the activating sleeve being maintained in its initial position by contact with the bottom of the cement basket, which is fixed to the mandrel by a shear screw.