Method for pipeline installation

• Main Authors: LANGNER CARL GOTTLIEB, BASS RONALD MARSHALL
• Format: Patent
• Language: English
• Published: 30.01.2001
• Edition: 7
• Subjects: BLASTING; ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVEFUNCTIONING OF MACHINES OR INSTALLATIONS; HEATING; JOINTS OR FITTINGS FOR PIPES; LIGHTING; MEANS FOR THERMAL INSULATION IN GENERAL; MECHANICAL ENGINEERING; PIPES; SUPPORTS FOR PIPES, CABLES OR PROTECTIVE TUBING; THERMAL INSULATION IN GENERAL; WEAPONS

A method for installing an offshore pipeline is disclosed in which the inner and outer pipes are structurally connected at a terminal end of a pipe-in-pipe flowline and centralizers are placed in the annulus to provide lateral support and maintain concentricity between the two pipes and to prevent buckling of the inner pipe. The working end of the pipeline is suspended under construction in a substantially vertical position within slips at the weld floor of a J-lay installation barge and sections of inner and outer pipe are added. Inner pipe is added by sections by grasping and orienting the section of inner pipe to a vertical position and the section is brought into abutting position with the inner pipe at the working end of the pipeline under construction, welded in place, and the weld is coated with an arc resistant material. Sections of outer pipe are added by grasping and reorienting to a vertical orientation, sliding the section down over the section of inner pipe just welded in place, bringing the section of outer pipe into abutting position with the working end of the pipeline under construction and welding it into place. The working end of the pipeline is then advanced through the slips to bring the end of the section of outer pipe added adjacent the weld floor and the foregoing steps are repeated as necessary to add additional sections of inner and outer pipe to complete the pipeline.