The North Sea Environment - Data Collection And Design Statistics

Abstract

Graham, C.G.; Marine Exploration Limited (MAREX -U.K.) American Institute of Mining, Metallurgical, and Petroleum Engineers, Inc. This paper was prepared for the SPE-European Spring Meeting 1975 of the Society of Petroleum Engineers of AIME, held in London, England, April 14–15, 1975. 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 request 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 discussion may be presented at the above meeting and, with the paper, may be considered for publication in one of the two SPE magazines. Abstract The offshore industry needs to know more about the North Sea environment to help it design structures and plan operations. Only a limited amount of measured data have, until recently, been available. Today, comprehensive data acquisition programmes are underway or are being planned. A review is made of these, and of the design statistics generated from the measurements. Introduction The severity and variability of North Sea weather are well known to those engaged in North Sea Oil Exploration and Production. The environment, in one way or another, influences virtually every aspect of offshore development, be it at the planning, design or field operational stage. There is a definite need for the offshore industry to increase its knowledge and understanding of the North Sea environment, and to quantify the range and kind of conditions likely to be encountered. The only way to achieve this, if it is not to depend upon theory alone, is for the industry to collect detailed measurements of the environment. For this to be effective, organised measurement programmes need to be set up; equipment must be carefully chosen and checked during operation to ensure data quality and reliability. This may be stating the obvious but, unfortunately, the amount of reliable data collected during the early exploration days is limited. Naturally, there have been problems (not least with the environment itself), but in relation to the potential benefits of reduced operational down-time and costs, there has been, until the last two years or so, a regrettable lack of investment in the North Sea data gathering. Even when measurement programmes have been initiated, returns have often proved low. This has sometimes been caused by unsuitable equipment but, more often than not, through insufficient emphasis being placed on regular equipment maintenance and calibration, and on personnel instruction - as basic as the need to change chart rolls and re-fill pens with ink. To-day, the situation is better, but there is certainly room for further improvement. Besides the data still being collected by the exploration rigs (with obvious gaps in the data for rig moves) and gas production platforms, there are now three consortia - each one oil platforms, there are now three consortia - each one oil industry and British Government sponsored - operating weather ships at three strategic locations around the U.K. Continental Shelf With the coming of the fixed steel and concrete production platforms throughout the North Sea, the future is likely to see the establishment of a new breed of offshore weather stations. The collection of the data represents only half the picture. picture. P. 11