Shell Oil Comapny

Exxon Production Research Company

Frans F Kopp

Ronald Marshall Bass

Ray R Ayers

Carl G Langner

Joe O Esparza

Thomas E Long

Edward H Phifer

David S McKeehan

Apparatus and method are provided for connecting electrical power for heating subsea pipelines after the pipeline is deployed. Electrical connections may be made subsea using wet-mateable connectors. The electrical power may be supplied from a boat or may be supplied from a host structure. A Remotely Operated Vehicle may be used to make the subsea electrical connections. Single Heated Insulated Pipes, Pipe-in-Pipe, heat tracing and other configurations for heating may be employed. The deployment of cables and other equipment for heating may be delayed until a need or potential need for heating or the probable locations of impediments to flow are identified in the subsea pipeline.

Making subsea pipelines ready for electrical heating

An subsea pipeline system having jumpers (short segments connecting equipment or wells and the main segments) that can be electrically heated is provided. The jumpers are heated by induction coils placed around the jumpers, either before placing the jumpers subsea or afterward. Electrical power may be supplied to the induction coils from current flow in the walls of the heated segment of pipeline or from an external source such as from a subsea transformer or ROV.

Induction heating for short segments of pipeline systems

A heave compensating support system is disclosed for positioning a subsea work package. The present invention provides a subsurface buoy with a lift line connected to the subsea work package and a compensating lift line having a catenary loop below its connection to the subsurface buoy on one end and connected to a surface vessel on the other end, whereby the heave compensating support system elements cooperate to establish a natural frequency for the suspended subsea work package which materially differs from the average wave frequency acting upon the surface vessel.

Heave compensated support system for positioning subsea work packages

A clamp is disclosed which is capable of latching on to a buckle arrestor on a subsea pipeline which has been severed in the vicinity of the buckle arrestor. By severing the pipe in this location and utilizing the buckle arrestor to latch the clamp on to the pipe, a simple and reliable clamp is used. A method to recover such a subsea pipeline by severing the pipeline in the vicinity of the buckle arrestor and utilizing such a clamp is also disclosed.

Subsea pipeline recovery clamp

Tendon segments are fabricated on a laybarge, then temporarily stored on seabottom. When a tension leg platform is moored, two tow vessels pick up one end each of the finished tendon and tow it to deep water, with the tendon in a catenary shape. Upon arrival in deep water, one end of the tendon is released and allowed to free fall to its uprighted position. A special work boat then transfers the tendon to the tension leg platform for final installation.

Tension leg platform tendon installation by deep catenary tow

Subsea pipelay is accomplished by flying the pipestring underwater with the use of wings which provide sufficient lift to maintain the pipestring off bottom as it is towed.

Winged pipelaying

A remotely operable apparatus and method for determining from a remote location the distance and angular orientation between two structurally unconnected members, such as two sections of a subsea pipeline, is disclosed. The apparatus of the invention comprises generally two remotely releasable guide posts disposed, respectively, in known spaced relationships to the two structurally unconnected members and a remotely operable measuring template. The remotely operable measuring template is adapted to telescope axially and includes two ball and socket joints to compensate for misalignment or differences in elevation between the guide posts. In practicing the method of the invention, the remotely operable measuring template is positioned over and firmly attached to the guide posts. All movable joints of the template are then locked and the guide posts are remotely released. The guide posts may then be retrieved to the remote location in the same spaced relationship as originally disposed. The distance and angular orientation between the guide posts may then be measured at the remote location and the distance and angular orientation between the two structurally unconnected members may be computed from such measurement.

Growing community of inventors

Houston, TX, United States of America

Frans F Kopp