Marine riser conduit section coupling means

A marine riser conduit section coupling adapted to withstand high riser tension and bending loads encountered in deep subsea well drilling and production operations comprising:

• tubular portion means for connecting with the associated riser conduit section;
• flange portion means for abutting connection with another coupling connected to its associated riser conduit section;
• and
• outer surface configuration means extending circumferentially about said coupling and extending from said tubular portion means to said flange portion means for preventing stress concentration in said coupling, wherein said outer surface configuration means comprises a curve defined by substantially a quarter of an ellipse which extends from near the extremity of the tubular portion means toward the radial extremity of the flange portion means, wherein said ellipse has a major axis about twice the length of its minor axis and said major axis is parallel to the axis of the riser conduit section, and wherein said curve, as it approaches the flange portion means, becomes tangent to and merges into a radially outwardly extending linear portion having a slope of between about 8.degree. and 12.degree..

A marine riser system adapted to withstand high riser tension and bending loads in deep subsea well drilling and production operations comprising:

• a plurality of connected riser conduit sections, each conduit section having at its two ends an integrally attached coupling by which each conduit section is connected to the adjacent conduit section;
• wherein each said coupling comprises:
• a tubular portion means for integral attachment with its associated riser conduit section;
• a flange portion means for abutting connection with another flange portion means of another coupling which is integrally attached to its own associated riser conduit section;
• and
• outer surface configuration means extending circumferentially about said coupling and extending from said tubular portion means to said flange portion means for preventing stress concentration in said coupling, wherein said outer surface configuration means comprises a curve defined by substantially a quarter of an ellipse which extends from near the extremity of the tubular portion means toward the radial extremity of the flange portion means, and wherein said ellipse has a major axis about twice the length of its minor axis, and said major axis is parallel to the axis of the riser conduit section.

A marine riser system adapted to withstand high riser tension and bending loads in deep subsea well drilling and production operations comprising:

• a plurality of connected riser conduit sections, each conduit section having at its two ends an integrally attached coupling by which each conduit section is connected to the adjacent conduit section;
• wherein each said coupling comprises:
• a tubular portion means for integral attachment with its associated riser conduit section;
• a flange portion means for abutting connection with another flange portion means for another coupling which is integrally attached to its own associated riser conduit section;
• and
• outer surface configuration means extending circumferentially about said coupling and extending from said tubular portion means to said flange portion means for preventing stress concentration in said coupling, wherein said outer surface configuration means comprises a curve defined by substantially a quarter of an ellipse which extends from near the extremity of the tubular portion means toward the radial extremity of the flange portion means, wherein said ellipse has a major axis about twice the length of its minor axis and said major axis is parallel to the axis of the riser conduit section, and wherein said curve, as it approaches the flange portion means, becomes tangent to and merges into a radially outwardly extending linear portion having a slope of between about 8.degree. and 12.degree..