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Marine Policy 30 (2006) 605623 www.elsevier.com/locate/marpol
The Louisiana articial reef program
Mark J. Kaiser
Center for Energy Studies, Louisiana State University Energy Coast & Environment Building, Nicholson Extension Drive, Baton Rouge, LA 70803, USA Received 16 September 2004; received in revised form 12 April 2005; accepted 26 April 2005
Abstract The Louisiana articial reef program (LARP) is the largest rigs-to-reef program in the world, and is unique in its almost exclusive use of oil and gas structures for reef construction. In 1986, Louisiana became the rst state to create an articial reef program under the guidance of National Fishing Enhancement Act and authorization of the Louisiana Fishing Enhancement Act. Currently, LARP has created over 83 articial reef sites using over 120 decommissioned platforms. Operators that donate a platform as an articial reef can often lower the cost of decommissioning below the cost to bring the platform to shore for disposal. Many factors are involved in the decision to convert a rig into a reef, and subsequently, the cost savings associated with reeng. The purpose of this paper is to describe the regulatory background of LARP, to discuss the nature of the cost savings associated with reef donation, and to derive quantitative relations that predict the donation amount based on characteristics of the structure. The frequency of rig donations as a function of water depth and planning area are provided, and regression models of the donation are developed based on the structure size, water depth, removal method, and proximity of the platform to the permitted reef site. Priorities for future research are also identied. r 2006 Elsevier Ltd. All rights reserved.
Keywords: Articial reefs; Decommissioning; Ocean development; Conservation strategies
1. Introduction Offshore platforms have been an important component of both the recreational and shing industries in the Gulf of Mexico (GOM) and have long been recognized as de facto articial reefs [13]. Shortly after an offshore structure is installed, sessile invertebrates such as barnacles, oysters, mussels, and sponges attach to the underwater frame, attracting mobile invertebrates and sh species, which in turn attract larger sh that feed upon them, and so on, forming a highly complex and interrelated food web. Once an offshore structure is removed to shore, however, the articial reef habitat is eliminated and the associated biological community is seriously affected. Various platform faunal studies have been performed over the years [46], but it is still a matter of scientic debate the degree to which articial reefs attract and produce shery resources. For a good review of the attraction versus production debate, see [7].
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In the federally1 regulated Outer Continental Shelf (OCS) of the GOM, nearly 4000 structures and 33,000 miles of pipelines are currently in use in the production of oil and natural gas. The types of structures and range of congurations vary widely, but shallow-water structures dened as structures in water depth less than 1000 ft generally consist of three main elements [8]: 1. A tubular steel structure, called the template or jacket, which extends from the seaoor to above the waterline and is used to support the deck and topsides equipment; 2. Steel pipe piling driven through the jacket legs into the seaoor to provide the platform foundation; and 3. One or more deck sections placed on top of the jacket to hold the drilling and processing equipment, heliport, quarters, and related infrastructure.
1 The federally regulated waters of the GOM begins seaward three nautical miles offshore the Louisiana, Alabama, and Mississippi shorelines, and nine nautical miles from the Texas and Florida shorelines, and extends 200 miles through the Exclusive Economic Zone.
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606 M.J. Kaiser / Marine Policy 30 (2006) 605623
Fig. 1. Caisson structures. Source: Twachtman Synder & Byrd, Inc.
Fig. 2. Well protector and xed platform structures. Source: Twachtman Synder & Byrd, Inc.
In addition to these three basic elements, offshore structures may also contain, depending on the function of the structure, 4. Conductors, which are used to conduct the oil and gas to the surface; 5. Topsides equipment, such as compressors, cranes, drills, heat exchangers, meters, power generation units, pumps, separators, scrubbers, tanks, etc.; and 6. Bottomsides equipment, such as cable, manifolds, pipelines, owlines, risers, umbilicals, wellheads, etc. Offshore development strategies vary depending upon the time of development; reserve size; proximity to infrastructure; and operating, economic, environmental, and strategic considerations. Shallow water developments in the GOM typically employ caissons (Fig. 1), well protectors and xed platforms (Fig. 2), and subsea completions (Fig. 3).
A caisson is a cylindrical or tapered tube enclosing a well conductor and is the minimum structure for offshore development of a well. Structures that provide support through a jacket to one or more wells with minimal production equipment and facilities is referred to as a well protector. Subsea systems include seaoor and surface equipment: seaoor equipment includes subsea wells, manifolds, control umbilicals, and owlines; surface equipment includes the control system and other production equipment located on a host platform. Production from caissons, well protectors, and subsea completions is sent to processing facilities on a xed platform prior to being transported to shore. Fixed platforms resemble the jacket structure of well protectors, but are larger and more robust, self-contained structures that include facilities for drilling, production, and combined operations. The distribution of GOM structures according to type, water depth, and planning area is shown in Table 1.
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In the deepwater GOM, compliant towers, spars, subsea systems, tension-less platforms, and oating production units are employed (Fig. 4), but in signicantly smaller numbers (Table 2). Fixed platforms have an economic water depth limit of about 1500 ft, while compliant towers are viable for water depths ranging between 1000 and 3000 ft. Tension leg platforms (TLPs) a...
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