Abstract: The present invention relates to improvements in drill slip assemblies for use in holding a drill pipe or other tubular member in a vertical position above or within a wellbore. The invention comprises a plurality of slip segments assembled in a slip bowl, each segment containing a plurality of dies which grip the tubular member to prevent any axial displacement. The invention provides at least three improvements over prior art drill slips. First, the outer surface of the slip segment assembly, particularly the lower nose region, is fully supported by the inner surface of the slip bowl such that no portion of the slip segment assembly extends below the bowl. Second, the slip segments are fabricated from forged steel, making them more durable and able to carry higher loads. Third, each die in the lowermost set of hardened dies is fabricated having a rounded bottom end with a tapered profile to complement the rounded bottom of the axial grooves cut into each slip segment.

Abstract: The present invention provides a drop ball sub that may be used to drop a large ball having an outer diameter larger than the inner diameter of a restriction in the wellbore such as the running tool used to run a first casing string through a second casing string. A smaller ball is used to control dropping of the large ball. The smaller ball has an outer diameter smaller than the restriction. The drop ball sub of the present invention may be used to operate any downhole tool that would benefit by receipt of a large ball. By dropping a larger ball, in one use of the invention larger valves can be controlled in the float equipment that provide a larger fluid flow path. A larger fluid flow path reduces surge pressure and enables the system to handle more debris. The present invention provides a system that preferably provides for a diverter tool above the running tool and a diverter tool below the running tool.

Abstract: Method and apparatus are disclosed for use in cementing a tubular member which is run into a borehole using a drill string. A landing collar is attached to the tubular member near the bottom of the tubular member, and the landing collar has an opening at least five inches in diameter. A liner wiper assembly is releasably suspended from the drill string. The liner wiper assembly comprises a lower liner wiper plug comprising float valves and an upper liner wiper plug. With the method and apparatus of the present invention, plugging problems are minimized.

Abstract: Slip assemblies are provided for gripping drill pipe or other tubulars such that the load is distributed along the length of the dies of the slip segments rather than being concentrated at the lowermost dies within the slip segments. The load is distributed by the fact of using a load ring around the interior surface of each slip segment to allow the load ring to absorb part of the loading rather than have all of the load supported by the lowermost slip dies. In addition, resilient members are provided at the top surface of the uppermost die and also at the top surface of the die immediately underneath the load ring to better distribute the loading between the various slip dies and also to lessen the possibility of having gaps develop between the dies of the slip segments.

Abstract: A system for reducing pressure while running a casing liner, hanging a casing liner from a casing and cementing the liner in a borehole during a single trip downhole is disclosed. Some of the components of the system are 1.) a bypass or diverter sub for reducing surge pressure having either an incremental breakaway seat or a yieldable seat, 2.) a container or manifold for launching a smaller ball used to close the bypass, a larger ball used to hang the liner in the casing, and a drill pipe wiper dart for cementing, and 3.) a guide shoe with multiple openings and no float valve to provide proper flow of drilling fluid up the liner and out the port of the bypass to reduce surge pressure and to provide for proper cementation. Advantageously, methods for operation of this surge pressure reduction system and its components are also disclosed.