Abstract: An apparatus for detecting substantially longitudinal flaws in the end area of a tubular member is disclosed. The apparatus comprises magnetizing-detection units, means for moving-said units along a helical path about the surface of the end area of the tubular member, and means for centralizing and securing the apparatus on the end of the tubular member being inspected. Magnetic detection transducers on the magnetizing-detection units detect perturbations in the applied magnetic field in the area of any substantially longitudinal flaws. The magnetic detection transducers are mounted so as to remain remote from the surface of the tubular member during operation of the apparatus. The field is generated in the tubular member by said magnetizing-detection units. The magnetizing-detection units are pivotably mounted to allow for movement over both flat and tapered surfaces. The signals generated by the magnetic detection transducers are transmitted to an external indicating device through slip rings.

Abstract: A guidance system for centering and guiding various drill strings or risers within a moonpool of a floating structure, e.g. a caisson vessel. The system comprises one or more guidance vehicles. Each vehicle is movably mounted on a separate track. The tracks, in turn, are spaced about the moonpool wall and extend vertically along the wall of the moonpool from the top of the moonpool to a point near its bottom. Each vehicle has a frame and means to mount the frame on its respective track. Two side arms and a center arm are pivotably mounted on the frame and are movable between a closed position and an open position. Mounted at the outer end of each of the arms is an interchangeable workhead assembly which engages a drill string or riser to center and guide the drill string or riser when the arms are in their closed position. Individual lines controlled by winches above the moonpool are attached to each vehicle for independently raising and lowering that vehicle within the moonpool.

Abstract: A system for guiding a drill string with an attached umbilical line through a moonpool of a floating structure. The system comprises a support means, and a workhead assembly secured to the outer end of the support means. The workhead assembly is adapted to engage the drill string and umbilical line without damaging the umbilical. The workhead assembly comprises a turntable support, which is secured to the support means, and a turntable. The turntable is positioned about the drill string and umbilical, and rests on the turntable support. Rollers on the turntable allow the drill string and umbilical line to move vertically through the turntable. Roller units on the turntable support allow the turntable and the engaged tool string and umbilical to rotate with respect to the support means.

Abstract: A method and apparatus is disclosed for eliminating vertical motion of a downhole tool in a subsea borehole as the tool is being operated by a drill string from a floating vessel. A vertical motion elimination means is incorporated into the drill string at a point which will be adjacent a blowout preventer stack on the marine bottom when the downhole tool is positioned at a desired point in the borehole. The vertical motion elimination means is comprised of a sleeve which is rotatably mounted on the drill string at a fixed vertical position. The sleeve is adapted to be engaged by the blowout preventer stack to fix the sleeve against vertical movement with respect to the preventer. Since the sleeve, itself, is fixed against vertical movement on the drill string, that portion of the drill string which lies below the preventer (hence, the downhole tool) will also be fixed against vertical motion within the borehole.

Abstract: A piggable fluid swivel comprising a first element on which a second element is rotatably mounted. Grooves in both the first and second elements align to form a continuous flow passage between the elements. Openings are provided through the first and second elements and into the flow passage whereby fluid can enter through one element, flow through at least a portion of the flow passage, and then exit through the other element. A flow barrier means similar to a gate valve is provided on one of the elements and includes a baffle plate that is extendable between an open position and a closed position. In an open position, the elements can be easily assembled and disassembled. In a closed position, the baffle plate blocks backflow in the fluid passage which allows pressure to build behind any pig that may become stuck in the flow passage to free the pig and carry it from the swivel. The swivel may be coaxially stacked to provide a multiline piggable fluid swivel.