Fixed Steel Offshore Structure Design - Past, Present & Future
Authors: Wisch D.J. 
Published: October 2008

An overview of the historical evolution of the design of fixed steel offshore structures and the inter-related development of API RP 2Aand the ISO Fixed Steel Standard is provided from the beginnings of the industry in 1947 to projections and a vision for a path forward. The trends, events and drivers impacting the design aspects will be addressed.

Introduction

The offshore structures industry has developed to a maturity level in 50 years to equal or exceed the maturity levels in other more common application arenas such as buildings and bridges. The industry attracted the best and brightest to work in exciting area that was constantly changing and provided a continuous feedback loop on success and failures. Having reached a level of relative maturity, a series of challenges are now present to strive towards optimization of the field from a balanced safety and investment perspective. While drilling and production operations over water have been around for 100 years now, the birth of the offshore industry is generally ascribed to the 1947 steel platform installed in 20 feet of water offshore the coast of Louisiana. Prior to that time, most "offshore" operations were based from wooden piled decks connected to shore by way of trestles. Other offshore style platforms were erected in the marshes of oil producing areas or inland seas as was the case in the Caspian area in the early 1900's. In the span of 22 years, the industry went from beginnings to issuance of the first "standard", the 1st Edition of API RP 2A'. In the ensuring 29 years, numerous practices and standards have evolved until today when there is somewhat a convergence of standards underway. This paper will provide an overview of the design practice over past 50 years, an assessment of the present practices and thoughts concerning the future directions. The elements of design, the process of design and the underlying philosophy of design continues to evolve.

The Start

The reader is referred to Veldman and Lagers2 for an excellent history of the offshore industry. This manuscript outlines the drama, risks, successes, innovations, companies and individuals contributing to today's offshore industry. Dunn2 provides an excellent review of the key milestones in offshore platform history through the 1970s in his 1994 OTC paper. While both of these references provide overviews of offshore facilities, the evolution of the design process is not developed. The 1947 Kerr-McGee platform was an extension of conventional design while at the same time a bold new approach in concept that still endures. Observation of the previously utilized "offshore" platforms illustrates the use of vertical piles, usually wood, often braced with diagonal members between the piles, and topped with wooden decking. Though the Kerr-McGee platform designed and installed by Brown & Root is widely regarded as the first offshore platform since it was the first producing offshore platform, parallel developments undertaken by Superior Oil and J. Ray McDermott earlier in 1947 also contributed to the design fundamentals.