Underwater well completion method and apparatus

Claim 1

A string of pipe installed in substantially vertical position with a portion of said pipe string buried in the sea floor and a portion of it suspended in the water above said sea floor, comprising male and female coupling elements rigidly affixed to adjacent ends of upper and lower joints of said pipe string, with the male element telescopically received within the female element, a plurality of circumferentially spaced-apart no-lead threads on the inner circumference of said female element and on the outer circumference of said male element, the threads on each being in alignment with the spaces between the threads on the other element, said threads being engaged with each other to prevent said pipe joints from moving axially apart the application of a tension force thereon, an annular shoulder on one of said elements in engagement with the other element preventing said pipe joints from moving axially toward each other, a fixed stop on one of said elements in engagement with the other element positioned to prevent relative rotation of said elements in one direction, and a movable latch on one of said elements in engagement with the other element positioned to prevent relative rotation of said elements in the other direction, and adapted to be moved to allow disengagement of said elements by relative rotation of said elements in said other direction without relative axial movement, followed by relative axial movement of said pipe joints away from each other in the absence of relative rotation, whereby said coupling elements may be engaged with each other and latched to maintain such engagement above the surface of the water, provide support means for supporting said lower pipe joint without disengagement while said pipe string is being lowered through the sea water, and provide means through which a driving force may be exerted to drive the lower pipe joint into the sea floor.