Weight and space requirements of offshore processing facilities can be used as parameters indicating a relative cost level of the installation. Of the two, weight is the easier to quantify. The operating weights of certain such production facilities are presented in this paper. The overall weight is broken down into a limited number of sub-groups, and the results are compared. Based on these results some ways and means of reducing the weights are discussed. All data used in this paper are as-built weights from North Sea installations. The paper further highlights the importance of keeping good control over platform weights, not only by keeping within weight estimates, but by looking at weight minimizing as a worthwhile optimization exercise.
The overall function of a primary producing facility whether on land or offshore, is to produce hydrocarbons in a sound and economic way. Offshore, platform size is one important parameter affecting costs of an installation and keeping the size down will generally help projects economics. This size will, by common sense, be dependent on platform function, but often the physical dimensions of a platform bear little relation to the functions of the platform. Indeed, when looking at the weights of some recent North Sea projects, it is difficult to see any sensible relationship between platform capability and the weight of the facilities. Nevertheless, little has been done to carefully investigate why, consequently, certain platforms become too heavy.
In a number of engineering disciplines optimization is common. The object thus being to find, not only one way of doing it, but the best way of doing it. With the cost of the platform in mind, how to do it smallest and lightest, ought to be regarded as an optimization study in itself. Because most certainly, by looking at some past projects, the size varies considerably, and there past projects, the size varies considerably, and there is room for savings in most of them.
