Introduction

As described in Chapter 1, the general arrangement and layout of ship-shaped offshore units designed for oil and gas operations may be grouped into several major parts: hull structures including storage tanks, topsides (processing facilities), export facilities, mooring facilities, accommodations, machinery space, subsea systems, and flowlines. All of these various parts are equally important to achieve successful operation, with due consideration of safety, health, environment, and costs versus benefits.

This chapter focuses on topsides, moorings, and export facilities. The material presented herein is aimed at the nonspecialist introductory reader. It is consistent with the content of this book and is included, primarily, to complete the coverage of the various aspects relating to ship-shaped offshore units.

Topsides consist of processing facilities that are typically located as elevated modules that are several meters (say, 3m or more) above the main deck of the vessel hull, but related piping systems may be located on the main deck of the vessel hull. Depending on the vessel size and topsides layout, the topsides modules may have multiple decks that contain the oil-, water-, and gas-processing facilities; utility systems; and similar functions. The preferred configuration, however, may be that to the extent possible, the topsides facilities would be incorporated as single-layer “pancake” units. The single-layer unit arrangement requires a larger main deck area for a given set of needs.