Deep Down Completes Installation Project in the Gulf of Mexico

Deep Down Inc. developed a unique installation and recovery procedure for a major operator in the Gulf of Mexico that allowed a new subsea well to be brought online nearly a year earlier than would have otherwise been possible due to long lead times in the delivery of umbilicals and flexible flowlines. The operator contacted Saipem to recover a decommissioned flexible flowline Jumper and use an existing umbilical to control a new well with minimal hardware and installation costs.

Saipem contracted Deep Down to develop and manage the installation and recovery procedures in approximately 2,750 feet of water, using its innovative techniques and support services, and to deploy its ancillary equipment and personnel to augment Saipem's ROV construction vessel capabilities. This work had to be performed at very fast pace.

Deep Down used its specialized, modular, compact HDU (horizontal drive unit), mini carousel and 5 ton tensioner to recover a 4" Wellstream flexible flowline jumper with Oilstate connectors on both ends. The flowline was shipped onshore to be cut in half. Each end was terminated with a flanged interface and successfully hydrotested.

A 2,910-foot-long composite jumper, conceived by the operator, was created at Deep Down by placing the flexible flowline jumpers on each end of a 1800 foot length of spooled 4" coiled tubing. Flanges were welded on and then x-rayed. Thermoplastic bend limiters were added to the end of the flexible to coiled tubing interface along with the original bend limiters that were on the oilstates end of the jumper. Deep Down filled and tested the composite well jumper and then dewatered it with Nitrogen.

A special 30-ton, 4-track tensioner was used to successfully install and connect the composite jumper on both ends in approximately 24 hours. The purpose of the jumper was to extend an existing flowline to the new well. The installation tension was 15 tons. After the jumper was installed, the empty Deep Down carousel was used to recover the SUTA (Subsea Umbilical Termination Assembly) and 2.5 miles of umbilical towards the platform and immediately re-laid towards the new well.

"We were able to work in the harshest time of the year within very small weather windows to recover a jumper, install a new 2,900-foot-long 4" composite well jumper, and recover several miles of umbilical, relaying it to a completely different location in three days," said Ron Smith, Deep Down's president and CEO.