US 5,360,239 AGranted

Threaded tubular connection

AssigneeAntares Marketing, S.A.

InventorErich F. Klementich

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Abstract

Threaded tubular interference fit interconnections and related production techniques are disclosed that are for example useful with large diameter tubular members, including pipe bodies, that can for example function as casing for oil, gas, geothermal, disposal and other wells. In a preferred aspect of the invention there is root-to-crest and/or flank-to-flank interference between nose and inner portions of male and female threads of the disclosed interconnections, such as substantially to seal them against leakage at the maximum internal and/or external pressure rating of the pipe body, and a run-out portion of the male thread and a corresponding portion of the female thread engage one another with interference to retain threaded engagement between said run-out and corresponding portions at the maximum axial force rating of the pipe body and also at the maximum internal and/or external pressure rating of the pipe body. These connections, when applied to API line pipe or other tubular products, can allow them to properly function as large diameter casing exhibiting easy and economical manufacture with existing machinery, easy installation in the field, good balance between geometric and load capacity transparency, and freedom from some undesirable characteristics of prior products.

Claims77

Dependent claims

In combination, a length of threaded pipe comprising a pipe body, a male thread with a run-out portion and regular turns having load flank, stab flank, crest and root, and a female member with female thread to enable coupling of said pipe to a further length of said threaded pipe to form a threaded connection, said combination comprising:

A. said male thread being tapered over at least a portion of its axial length, including a nose portion thereof,
B. said female thread being tapered over at least a portion of its axial length, including an inner portion thereof which threadably engages with said nose portion when said threads are in made-up position,
C. said male and female threads having load flank angles and thread heights sufficient to ensure that with the threads in made-up position in the threaded connection, at least the load flank of the male thread of said connection will remain engaged with the load flank of the female thread of said connection, even in response to an axial load on said connection substantially corresponding to the axial yield strength of the pipe body;
D. said male and female threads being so dimensioned in relation to each other at said nose and inner portions to ensure that in made-up position in said connection a root-to-crest and/or flank-to-flank interference fit will exist between said nose and inner portions, said interference being sufficiently large for forming in the threads, with the aid of thread compound present in gaps which may optionally exist between said male and female threads, a seal that substantially prevents leakage of fluid through the threads
1. when the connection is subjected to internal fluid pressure corresponding to the internal pressure rating of the pipe body;
or
2. when the connection is subjected to external fluid pressure corresponding to the external pressure rating of the pipe body;
and
E. said male and female threads being so dimensioned in relation to each other that in made-up position in said connection the run-out portion of the male thread will engage a corresponding portion of the female thread in an interference fit, said interference being sufficient to retain threaded engagement between said run-out and corresponding portions
1. when the connection is subjected to axial tension corresponding to the axial yield strength of the pipe body and to internal fluid pressure corresponding to the internal pressure rating of the pipe body, or
2. when the connection is subjected to axial tension corresponding to the axial yield strength of the pipe body and to external fluid pressure corresponding to the external pressure rating of the pipe body,
and said interference being less than that which will cause either substantial destructive hoop stress yield deformation of said pipe or female member or substantial destructive galling of said male or female threads.

9 more elements

In combination, a length of threaded pipe comprising a pipe body with male thread turns having load flanks, stab flanks, crests and roots and a female threaded member for coupling of said pipe to a further length of threaded pipe to form a threaded connection, said combination comprising:

A. said male thread having a hook profile and being tapered over at least a nose portion of its axial length,
B. said female thread having a hook profile matingly compatible with the male thread profile and being tapered over an inner portion of its axial length which will threadably engage with the nose portion of said male thread in made up position,
C. at least one of said threads having its surface roughened in an irregular manner to assist in retention of a thread compound in place at the surface thereof, and
D. said male and female threads being so dimensioned in relation to each other
1. to provide a root to crest or flank to flank gap between them and
2. to ensure that a root to crest or flank to flank interference fit will exist between them in made up position,
3. said interference being sufficiently large and said gap being sufficiently small to substantially prevent, with the aid of thread compound therein and without substantial destructive galling of the threads, leakage through the nose and inner portions thereof
a. when the connection is subjected to internal fluid pressure corresponding to the internal pressure rating of the pipe body and to axial tension corresponding to the axial yield strength of the pipe body, or
b. when the connection is subjected to external fluid pressure corresponding to the external pressure rating of the pipe body and to axial tension corresponding to the axial yield strength of the pipe body.

6 more elements

Dependencies are inferred from the claim text.