Installation of the Bullwinkle Platform

ABSTRACT The installation of the Bullwinkle Platform is documented. The objective is to provide a record of the installation plans and the field execution of these plans. The paper should be of interest to those charged with the responsibility of planning for future deep water platform installations. INTRODUCTION The Bullwinkle Platform is a self-contained drilling and production platform recently installed in the Gulf of Mexico, approximately 160 miles south-southwest of New Orleans. Louisiana. The water depth at the Green Canyon Block 65 site is 1353 feet. The platform is basically a conventional template type structure with horizontal jacket dimensions of 135 by 158 feet at the top (plus-15-foot elevation) and 400 by 480 feet at the mudline. The platform is supported by twenty-eight 84-inch diameter skirt piles. The decks are designed to support two full-size drilling rigs. Sixty well slots are provided but only fifty conductors were initially installed. Permanent production facilities will be installed after the drilling program has been completed and the rigs are removed. The platform is owned and operated by Shell Offshore Incorporated and was designed by the Civil Engineering Group of Shell Oil Company. The jacket and well conductors for the platform were fabricated by Bullwinkle Constructors (subsidiary of Gulf Marine Fabricators) at Ingleside. Texas. The piles and deck sections were fabricated by McDermott Marine Construction near Morgan City. Louisiana. The platform was installed by Heerema Marine Contractors, working as a subcontractor to Bullwinkle Constructors. The installation procedures were developed by Heerema Engineering Service. Other aspects of the Bullwinkle Project are discussed in References 1 through 10 and Reference 13. It is the belief of the authors that a paper of this type should 1) should describe in general what was done and 2) discuss in reasonable detail all problems that were encountered. It is believed that this approach will be the most useful to the offshore industry in general and to those planning for similar operations. The authors do wish to clearly emphasize. However, the successful installation of the platform, which included a number of "firsts" for the offshore construction industry. The success is due largely to the thoroughness and care with which the effort was planned. SUMMARY OF INSTALLATION PROCEDURE The Bullwinkle jacket was transported to the installation site on Heerema's launch barge "H-851". Positioning lines from four tugs and two anchor lines from the crane vessel "Odin" were connected to the jacket prior to launch. Some free flooding of the lower end of the jacket was permitted after launch, but it was not sufficient for the jacket to completely self-upend. Personnel boarded the top of the jacket to complete the ballasting operations using a preinstalled control panel. The upending control system is discussed in Reference 10. The jacket was positioned on bottom by additional flooding without crane assistance. The piles were all fabricated to full length and transported to the field on a single cargo barge.