Flexible/Umbilical recovery: Garden Banks 388
Authors: Witherow Karl , Charlson Alan , Franklin Robert 
Published: October 2008

Cameron's Free Standing Production riser was first installed in 1986 at Green Canyon Block 29, in 1522 FSW to produce oil and gas to Placid Oil company's Penrod 72 drilling and production facility. Oceaneering installed an ROV and surface diving equipment on the floater to facilitate installation, production and maintenance. The production riser technology was proven when oil and gas were successfully produced a short time later. The riser and production facilities were removed several years later when the field reserves proved to be smaller that originally predicted.

Ten years later Oceaneering was again contracted, this time by Enserch now EEX Corporation, to install an ROV and surface diving systems to assist with the installation of the Cameron Free Standing Production Riser System. EEX purchased and refurbished the system for installation in Garden Banks block 388 in 2100 FSW. The riser system was installed and tied back to another semi submersible drilling production facility aptly named Garden Banks 388. The second installation proved the technology again with oil production shortly after installation.

Oceaneering's ROV and diving crew were continually assisting EEX with the installation of additional flexible flowlines, the change out of tension wires, performing ABS inspections, and other task required to maintaining the production facilities and maximize production over the next two years.

In late 1999 Bob Franklin, with EEX, directed Oceaneering to develop a plan to provide ROV and surface diving procedures for the decommissioning of Garden Banks 388. EEX asked Oceaneering for lumps sum pricing to provide surface diving and ROV support for the removal of twenty two flexible flowlines, 8" and 12" flexible export lines, two 2500' control umbilicals, and the subsea hardware associated with the free standing riser system. The decommissioning activities would bring together several contractors working on separate lump sum contracts with the common goal of removing the hardware, while preserving the re-usability of the Free Standing Riser System.

Fast Track Contracting and Excutation

To take advantage of favorable summer weather conditions in the Gulf of Mexico, EEX decided to fast track the decommissioning activities for Garden Banks 388. Oceaneering was selected to support the operations with ROV and surface diving personnel with equipment already in place on Garden Banks 388. Cal-Dive International was selected as the prime contractor for the well kill, pigging, and removal operations.

EEX required the contractors to submit lump sum pricing for separate scopes of work to be conducted simultaneously with out impacting the fast track schedule of sixty days. With out clear-cut procedures and work scopes identified, EEX relied on the experience of the contractors to develop their scope, schedule and pricing accordingly. Oceaneering brought in Superintendent Alan Charlson who had installed this system both at Placid's GC-82 location and EEX's GB-388. With Alan and Bob Franklin's experience, they developed procedures, identified and procured the tooling and materials needed for the work, as well as completing a comprehensive schedule in which lump sum pricing could be based.