Abstract: A retrievable whipstock which can be hydraulically set within a wellbore and following the drilling procedure mechanically released and retrieved for future use. The whipstock includes a whip which directs a milling tool from the main well and a hydraulically actuated packer or anchor for setting the whipstock in the wellbore. The retrieval tool includes a nose piece to ensure proper orientation relative to the whipstock and a die collar to threadably engage the whip. An adapter on the retrieval tool wedges the whip away from the casing wall to ensure mating engagement between the retrieval tool and the whip. The whipstock is released through the application of tension through the retrieval tool allowing removal from the wellbore.

Abstract: A system for maintaining an optimum pressure balance within an inner chamber of a drilling head for improved seal life and integrity. The system maintains a pressure differential across the seals thereby preventing well fluids from contaminating the seals and improving their useful life. The drive ring of a drilling head is rotatably supported by a series of bearings disposed within a bearing chamber. The secondary chamber of the drilling head is sealed to prevent contaminants from entering the chamber and fouling the seals. The seals withstand the borehole well pressures to prevent the introduction of contaminants, by maintaining a pressure differential across the seals. The present system compensates for variations in the borehole pressure. A pressure compensator is in communication with the borehole to activate a lubricant pump for increasing lubricant pressure within the inner chamber in response to increased borehole pressures.

Abstract: A drilling head for the controlled operation of the drill string while diverting well fluids from the well. The drilling head incorporates a kelly drive and at least one stripper rubber which rotate with the drill string extending through the drilling head. Rotation of the drive bushing and stripper rubber are controlled by bearings disposed in a bearing chamber of the drilling head through which lubricant is circulated to reduce friction and cool the bearings. A turbine ring attached to the lock nut ring of the kelly drive circulates lubricant through the bearing chamber as it rotates in association with the drive assembly of the drilling head. The turbine pump ring forces circulation of lubricant as the drive assembly rotates in addition to the circulation by the remove lubricant pump or in the event the remote pump fails to operate. The turbine ring includes a plurality of angular slots to force circulation of the lubricant as the drive assembly rotates.

Abstract: A one-trip whipstock assembly incorporating a hydraulically set anchor which includes an interlock for maintaining the anchor in its set position upon interruption of hydraulic pressure. The anchor is connected to the lower end of the assembly which also includes a whipstock for diverting cutting tools and a locator sub for positioning the assembly in the cased well bore. The whipstock assembly is designed to be run into the well using a running string or a mill attached to the upper end of the whipstock in order to locate and set the whipstock and mill the casing in only one trip.

Abstract: A stripper rubber for use in a drilling head to seal against a work string deployable through the drilling head. The stripper rubber is longitudinally restrained to prevent extrusion of the stripper under pressure and to reduce the tensile and compressive stresses on the stripper rubber. One embodiment of the stripper rubber incorporates upper and lower metal rings which are maintained in spaced apart relation by vertical rods thereby allowing radial expansion as tool joints pass through the rubber but prevents inversion of the stripper rubber under pressure. Reinforcing cords added to the stripper rubber increase the longitudinal strength. A second embodiment bonds a stripper rubber into a cylinder which restrains the rubber in the vertical direction. Radial deflection is accomodated by allowing the rubber to flow vertically as a tool joint passes therethrough. Each of the stripper rubbers incorporates an integrally formed drive bushing which facilitates mounting within the drilling head.