Apparatus for connecting underwater tubular members
A connector for severed pipes in a wellbore has an elongated tubular mandrel, a sealing pack-off ring mounted on the mandrel, an activator ring for pressing against the pack-off ring and causing the pack-off ring to seal an interior of a casing above a shut-off valve. A grapple member is slidable mounted on the mandrel above the activator ring; the grapple member has an enlarged diameter plate, which rests on an upper edge of a severed casing. A production pipe, control lines and production casing can be lowered through the large opening in the mandrel and re-establish connection with the severed casing and production pipes.
1. A method of re-establishing mineral production flow lines of an underwater wellbore, said wellbore having at least one casing and a production pipe with a shut-off valve extending through the casing, the method comprising the steps:
providing a connector apparatus comprising an elongated tubular mandrel configured for positioning inside said at least one casing in the wellbore, an activator ring member slidably mounted on the mandrel, a grapple member slidably mounted on the mandrel above the activator ring, a flexible resilient sealing ring mounted below the activator ring, said grapple member having a ring-shaped plate having an exterior diameter at least slightly greater than an exterior diameter of the casing;
severing the casing and the production pipe at a level above the shut-off valve along substantially horizontal line;
positioning a tubular member in a generally surrounding relationship over said severed casing; connecting an extension casing member to an upper end of the mandrel and lowering the mandrel and the extension casing member into the wellbore until said plate rests on an upper edge of said at least one severed casing within the wellbore;
applying a downward force on said activator ring, thereby causing lateral expansion of the sealing ring and sealing of interior of said at least one severed casing above the cut-off valve;
lowering an extension production pipe through the extension casing and the mandrel into the wellbore and connecting the extension production pipe to the severed production pipe in the wellbore; and
cementing an annular space between the extension casing and the tubular member.
2. The method of claim 1 , further comprising the step of providing said grapple member with a plurality of grapple hooks having upwardly oriented teeth for engaging an inner wall of said at least one casing and resisting an upward movement of the mandrel within said at least one severed casing.
3. The method of claim 2 , further comprising the step of providing said grapple hooks with an inclined inner surface and providing serrations on said inner surface.
4. The method of claim 3 , further comprising the steps of providing said activator ring with a frustoconical upper portion carrying a plurality of teeth and causing the teeth of the upper portion engage the serrations of the grapple hooks when the connector apparatus is in a set position.