Problems Associated With the Operation of Offshore Sea Water Injection Systems

Abstract

American Institute of Mining, Metallurgical, and Petroleum Engineers, Inc. This paper was prepared for the SPE-European Spring Meeting 1976 of the Society of Petroleum Engineers of AIME, held in Amsterdam, The Netherlands, April 8–9, 1976. 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 OF PETROLEUM TECHNOLOGY or the SOCIETY OF publication in the JOURNAL OF PETROLEUM TECHNOLOGY or the SOCIETY OF PETROLEUM ENGINEERS JOURNAL is usually granted upon request to the Editor PETROLEUM ENGINEERS JOURNAL is usually granted upon request to the Editor of the appropriate journal, 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 discussion may be presented at the above meeting and, with the paper, may be considered for publication in one of the two SPE magazines. Introduction OFFSHORE SEA WATER INJECTION SYSTEMS Offshore sea water injection systems are rapidly increasing in number. It wasn't many years ago that you could number the existing systems on the fingers of your hands. Offshore sea water injection systems have all the problems common to onshore systems plus a few problems inherent to their offshore location. Offshore sea water injection systems must be more dependable than onshore systems because of their remote locations and the difficulty of getting men and material on site. This is particularly true during winter operations in such locations as the North Sea. Supplies and spare parts cannot be received shortly after a phone call as is common with onshore operations. The high expense of offshore operations coupled with the high capital cost of the platform make it imperative that plans be platform make it imperative that plans be well thought out and complete before embarking on an offshore sea water injection project. project. DESIGN CONSIDERATIONS IN OFFSHORE SEA WATER INJECTION SYSTEMS There are a number of constraints imposed upon the design engineer when he switches from onshore to offshore sea water injection systems. These are imposed by high platform costs and by high offshore operating costs. The design engineer must: Minimize weight on platform Minimize space utilized on platform Minimize maintenance offshore Minimize supply offshore Minimize manpower offshore THE DESIGN BASIS The design basis is set by following the principle that the water quality must be only that which enables injection for the life of the project at a minimum injection pressure and minimum cost. pressure and minimum cost.