Garden Banks 189 "A" Deepwater Jacket Project
Authors: Curtis W.B. , Gilmore L.A. 
Published: October 2008

This paper describes situations associated numerous innovative and unique with the design, fabrication and installation of a Gulf of Mexico platform in 720 feet of water. The jacket fabrication included an innovative roll up technique used to reduce the fabrication schedule and minimize capital expenditures for cranes. The tow to the Gulf of Mexico from the fabrication yard encountered some unique obstacles. Very tight control of the launch barge was required to negotiate shallow water and numerous curves in the canal. The project management team was also challenged with a change in Installation Contractor when the fabrication was approximately forty (40) percent complete. The change in Installation Contractor at such a late date in the detailed engineering and fabrication phase required structural modifications to the jacket launch truss. The jacket was also fabricated with a docking framing system to mate the structure over an existing subsea template.

PROJECT SUMMARY

Garden Banks Block 169, called the TICK Prospect, is located in the Gulf of Mexico in 720 feet of water approximately 255 miles southwest of New Orleans (Reference Figure 1). This oil and gas field was discovered October 1966. The prospect was deemed viable in September 1969. The development goal was to achieve First production in the fourth quarter of 1!391. Fast tracking the engineering and construction phase of the project was utilized. Fast tracking reduced the overall cycle time, the time required from preliminary engineering through first oil production. The jacket was fabricated with a docking framing system and was installed over three existing exploratory wells previously drilled through a subsea template.

The Contracting Strategy for the jacket design, fabrication and installation scope of work reduced the typical cycle time for a project of this size by one (1) year. Preliminary jacket design bids were sent to three companies in the late summer of 1969. These bids were reviewed in the Fall of 1969. Two bidders were awarded the Preliminary Engineering Contract and the option to submit Final Jacket and Piling Design, Fabrication and Platform Installation bids in late December 1989.

The fast track contract for the Jacket Design, Fabrication and installation was awarded in late January, 1990. Detailed Engineering commenced on January 15, 1990. Detailed in place and installation engineering proceeded concurrently with jacket fabrication. Major steel was ordered in April and received in the fabrication yard beginning in June, 1990. Jacket fabrication was completed on schedule to coincide with the Installation

Contractor?s availability. The Jacket set sail on August 6, 1991 and installation was successfully days ahead of schedule on August 22, Figure 2)

1.JACKET FABRICATION

Jacket - Template interface

The jacket was installed over three existing exploratory wells in the subsea template utilizing the docking framing system. The template, installed in 1988, defined future well slot spacing at seven feet on center and the well bay orientation (reference 1990 OTC paper 6227). The nine slot template allowed for additional exploratory drilling with the potential for eventual production from these wells