HISTORIC OVERVIEW OF U.S. FIXED OFFSHORE PLATFORMS – PART III
This is the third of a three-part overview of the history of U.S. fixed offshore platforms. While this is a highly specialized aspect of engineering involving a comparatively small number of civil engineering professionals, it is an expertise that not only supports an industry that’s critical to the production of a most valuable national resource but also delivers on our ever-increasing demand for energy.
Industry collaboration, research, and trial-and-error drove the design of fixed offshore platforms, while investment capital fueled their construction and installation. Offshore oil & gas production’s lucrative economics funded fabrication yards, equipment, and heavy-lift derrick barges. The offshore industry has moved, transported, launched, and lifted the heaviest structures ever in each of these categories.
Construction required large areas with marine access, often in low-lying Gulf Coast locations needing reinforcement for heavy structures. McDermott and Brown & Root led construction and installation, with platforms mostly fabricated at McDermott’s Bayou Boeuf yard in Amelia, LA, and Brown & Root’s Aransas Pass yard near Corpus Christi, TX. By 1980 Brown & Root’s Harbor Island yard employed 500-workers, had 20-cranes including the first two Manitowoc 6000’s (500 t capacity),, and could fabricate jackets for depths up to 1,000-ft.
Fixed platform jackets grew too large for early marine cranes, requiring a new installation method known as a “launch” because the structure actually slid off the barge into the water. Jackets were then built on skidways, slid onto a barge using large winches, with frequent ballast adjustments to maintain stability. McDermott performed the first launch in 1956. Eventually barges were purpose built with rocker arms and skidways specifically for transporting and launching jackets with one of the largest being McDermott’s Intermac 650 built in 1980. After launch, derrick barges upended the structure and set it in place with driven piles.
The final step was setting the topsides decks, which required large transport barges and floating cranes that didn’t exist initially. The industry quickly developed derrick barges that could perform heavy lifting given the dynamic forces of the marine environment, eventually making it common to lift topsides weighing several thousand tons.
Jay Weidler, former Senior VP at Brown & Root, received the OTC Distinguished Achievement Award in 1995 for leadership in structural engineering. The Offshore Technology Research Center (OTRC) at Texas A&M University was founded in 1988 to support the industry’s push into deeper waters.
Top photo: McDermott Derrick Barge (DB) 7 commissioned in 1953 with 250 mt capacity which was the highest capacity at the time. McDermott built the first two derrick barges built specifically for offshore use and the first ones to have revolving cranes DB4 in 1949 & DB7 (McDermott.com). Bottom photo: Heerema, a Dutch company, derrick barge Sleipnir commissioned in 2019 with dual cranes each with a 10,000mt lifting capacity for a total dual lift capacity of 20,000mt (Wikipedia, Heerema.com).
The fixed offshore platform, like truss bridges, evolved through the contributions of many engineers such as Peter Marshall, Griff Lee, George Brown, Jay Weidler, and others. Their work combined knowledge, collaboration, research, and trial and error, resulting in the globally standard fixed platform design still supporting the energy industry today.
