Deep Water Structures
Authors: Cloyd Marshall P. 
Published: December 2007

Cloyd, Marshall P., Member AIME, Brown and Root (U.K.) Ltd.

This paper was prepared for the Second European Meeting of the Society of Petroleum Engineers of AIME, to be held in London, England, April 2–3, 1973. Permission to copy is restricted to an abstract of not more than 300 words. Illustrations may not be copied. The abstract should contain conspicuous acknowledgment of where and by whom the paper is presented. Publication elsewhere after publication in the JOURNAL paper is presented. Publication elsewhere after publication in the JOURNAL OF PETROLEUM TECHNOLOGY or the SOCIETY OF PETROLEUM ENGINEERS JOURNAL is usually granted upon requested to the Editor of the appropriate journal, provided agreement to give proper credit is made. provided agreement to give proper credit is made. Discussion of this paper is invited. Three copies of any discussion should be sent to the Society of Petroleum Engineers office. Such discussions may be presented at the above meeting and, with the paper, may be considered for publication in one of the two SPE magazines.

GENERAL:

In examining the problem of Deep Water Structures, it is important to assess the basic aspects of a platform. Fundamentally the need is for a load bearing system, which is sufficiently high, with respect to the water surface, so that various mechanical operations can take place in the dry. In the mineral extractive industries these are usually heavy loads, particularly in the most popular areas, oil and gas production.

The load bearing structure or platform may be solely devoted to the drilling operation and there are several variations of this, e.g. it may be a small well conductor platform that is straddled by a jack-up for the drilling operation, or it may be a tender platform where only the drilling rig and its directly imposed loads are supported, with the other loads such as mud and cement storage with associated handling and mechanical facilities, as well as drill pipe and casing, being held alongside on a floating vessel. The complete self-contained drilling platform is the ultimate in the pure drilling capability platform. When production capability is platform. When production capability is required in addition to the drilling capability in shallow waters, an individual production platform may be constructed which would have platform may be constructed which would have the necessary facilities for treating the gas, condensate and/or oil prior to shipment. However, a combined drilling/production platform is more frequently encountered in platform is more frequently encountered in deeper water where the higher capital investment increases the desire to be able to drill and produce from the same platform. This type of self-contained platform can normally provide both functions. However, in subsequent stages, the large drilling rig may be removed and possibly replaced with a workover rig while the remaining space is frequently utilized for gas injection or water flooding equipment.

The cost of deep water platforms has risen, principally as a function of the environmental conditions, and as a consequence larger finds are now required to make production profitable in these severe production profitable in these severe environments. As a result there is a desire to incorporate the storage capability, as part of a drilling/production structure. To date His has not occurred, however, for many reasons it probably will occur within a short period of time. period of time.