Abstract: A remotely operable apparatus and method for determining from a remote location the distance and angular orientation between two structurally unconnected members, such as two sections of a subsea pipeline, is disclosed. The apparatus of the invention comprises generally two remotely releasable guide posts disposed, respectively, in known spaced relationships to the two structurally unconnected members and a remotely operable measuring template. The remotely operable measuring template is adapted to telescope axially and includes two ball and socket joints to compensate for misalignment or differences in elevation between the guide posts. In practicing the method of the invention, the remotely operable measuring template is positioned over and firmly attached to the guide posts. All movable joints of the template are then locked and the guide posts are remotely released. The guide posts may then be retrieved to the remote location in the same spaced relationship as originally disposed.

Abstract: A method and apparatus for cleaning debris from the interior surfaces of two flowlines, particularly dissimilar sized flowlines, utilizes a crossover flowline, crossover valve, and two bypass flowlines and bypass valves, wherein the bypass flowlines communicate between a respective flowline and the crossover flowline.

Abstract: A method and apparatus for remotely replacing damaged guideposts attached to a subsea structure are provided. A receptacle is permanently attached to the subsea structure. The guidepost is inserted into the receptacle and is releasably connected thereto by one or more radially-oriented, spring loaded lock pins. Damaged guideposts are removed by applying an upward vertical force to the guidepost sufficient to shear the lock pin or lock pins. The upward vertical force is applied by a replacement tool capable of being remotely operated from the surface of the body of water. Following removal of the damaged guidepost, a new guidepost is inserted into the receptacle. Lock pins mounted in the new guidepost retract into the guidepost as it is being inserted. When fully inserted, the lock pins extend and engage a retaining groove formed in the receptacle thereby firmly locking the new guidepost in place.

Abstract: This invention is an electrical connector held together by flexible magnetic substrates which also form the support for the connector's electrical contacts. The connector has many uses but is especially suitable for the connection between sections of hydrophone streamer cables.

Abstract: A riser tensioner safety system for preventing damage to a floating drilling vessel in a broken cable event or an emergency disconnect of the riser is disclosed. The system uses standard pneumatic/hydraulic tensioning devices together with a safety valve which is installed in the hydraulic fluid supply line to the tensioning device. The valve is held open by tension in the riser tensioner lines. If tension drops below a predetermined level due to a broken cable event or an emergency disconnect of the riser, the valve closes rapidly preventing acceleration of the tensioner piston.

Abstract: An apparatus and method are disclosed for aligning equipment lowered from the ocean surface with a fixed subsea structure without the use of guidelines. The apparatus comprises a guide frame including primary and secondary members, a mating guide base including primary and secondary members, vertical channeling means and rotational engagement means. In the practice of the method, the frame is generally positioned above the base using known means of limited precision. Using remote means, the frame is first lowered to vertically channel the primary members into alignment, then rotated until the secondary members are engaged and finally lowered further to fully land the frame on the base.

Abstract: A method for preventing annular fluid flow following primary cementing of oil and gas well casings is disclosed. Pursuant to said method the casing is vibrated so as to maintain the hydrostatic pressure of the cement column surrounding the casing at or above the pressure of the fluids in the various formations penetrated by the well until the cement has acquired its initial set. The vibration may be either continuous or intermittent. Preferably, the vibration has a low frequency. The method may include the additional step of applying pressure to the surface of the cemented annulus while the cement is curing. The vibration may be induced in several ways. For example, the casing may be vibrated by simultaneous or sequential explosions of a slow-burning black powder. Alternatively, hydraulic jars may be used to strike blows on the casing causing the casing to vibrate.

Abstract: A thin shell pressure sensor for sensing in situ pressures in a medium in which the sensor is embedded is provided. The sensor operates on the principle that the membrane stresses near the apex of a thin shell under an external pressure load are proportional to the applied pressure. The constant of proportionality is dependent only on the geometry of the sensor.

Abstract: An apparatus is disclosed for minimizing the horizontal forces on an offshore arctic structure due to ice movement. The structure includes a base portion, sloped side walls and a smooth, unobstructed top portion. The structure is substantially submerged in a body of water with the top portion at or near the water surface permitting floating ice sheets which strike the side walls to flex slightly upward and advance along and over the structure without substantially destroying the overall integrity of the ice sheet. In this manner, the horizontal forces on the structure resulting from the ice sheet are minimized due to the elimination of a crushing failure mode of the ice sheet commonly associated with conventional offshore arctic structures.

Abstract: A method and apparatus for mitigating or eliminating the frost heave of refrigerated pipelines buried in frost-susceptible soil are provided. A blanket of heat absorbent material is placed over the pipeline on the surface of the soil to increase the flow of heat into the region surrounding the pipeline. This technique may be used in combination with other frost heave mitigation techniques, such as insulating the pipeline and supporting the pipeline with a heave resistant bedding material.