Hydril Company

John F Greenip

Robert S Sivley, Iv

Doug R Enderle

A seal for a radially expansible conduit connection is disclosed. The seal includes a first sealing surface disposed proximal to an end of a male portion of the connection and a corresponding second sealing surface disposed proximal to an end of a female portion of the connection. The first and said second sealing surfaces are substantially opposite each other upon connection of the male and female portions. The seal includes a first clearance surface proximal to the first sealing surface and a second clearance surface proximal to the second sealing surface. The first and second clearance surfaces are substantially opposite each other upon connection of the male and female portions. The first and second clearance surfaces, and the first and second sealing surfaces each have a diameter such that upon radial expansion of the male portion and the female portion after coupling together thereof, the clearance surfaces remain out of contact while the sealing a surfaces contact each other so as to develop a contact pressure. In one embodiment, the clearance between the sealing surfaces prior to expansion is about 30 to 40 percent of the amount of expansion. In another embodiment, the sealing surfaces are in interference contact prior to expansion. In one embodiment, the clearance surfaces have a clearance, prior expansion, of about 50 to 55 percent of the amount of expansion. In a particular embodiment, the conduit connection is a threaded coupling.

Collapsing type seal for expandable tubular connections

A stress reduction groove for tubular connections which relates to a threaded pipe connection, and includes a box member, a pin member, and a continuous groove formed in the thread of one of the members. The box member has a tapered, internal, generally dovetail-shaped thread with stab flanks, load flanks, roots, and crests. The internal thread has a beginning and an end and increases in width in one direction. The pin member also has a tapered, external, generally dovetail-shaped thread with stab flanks load flanks, roots, and crests. The external thread increases in width in the other direction so that the complementary flanks of the respective threads move into engagement during rotational make-up of the connection and form sealing surfaces that resist the flow of fluids between the threads upon rotational make-up of the connection. A section of one of the internal and external threads has the continuous groove formed in the roots thereof. The groove extends from either the beginning or the end of the one thread to a point between the beginning and end of the one thread, thereby reducing the pressure that develops between the sealing surfaces during rotational make-up in a thread lubricant applied to the threads.

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Houston, TX, United States of America

John F Greenip