U.K. North Sea Production Prospects to the Year 2000
Authors: Band G.C. 
Published: December 2007

Band, G.C., SPE, U.K. Offshore Operators Assn.

Summary.
This study by the U.K. Offshore Operators Assn. (UKOOA) used members' confidential reserve and production data to project future exploration possibilities in key areas of the U ' K. North Sea. When these data were combined with the inventory of existing but underdeveloped discoveries, it was possible to forecast a range of future levels of oil and gas production and the development effort required. This study highlights the potential significance of gas-condensate discoveries and projects one ambitious but technically achievable scenario to the year projects one ambitious but technically achievable scenario to the year 2000. Since this paper was first presented in late 1984, the sudden fall in oil prices during the first half of 1986 has resulted in the deferral of many potential oil and gas-condensate developments. Thus. while the reserve base remains unchanged and technical conclusions are still valid, the pace of development is likely to be much slower than the projected scenario, at least until prices recover in the 1990's.

Introduction
It is generally recognized that the exploration and development of the UKCS has reached a critical stage. Oil and gas production is near expected peak levels, a situation achieved by the discovery and rapid development of relatively few large fields. Future production is forecast to decline, and this trend can be moderated only by the development of a substantial number of existing and future discoveries. The discovery and development of future hydrocarbon reserves cannot be taken for granted. They depend on an effective UKCS licensing policy, vigorous exploration activity. cost-effective technology, and a combined energy pricing and fiscal climate that will encourage the pricing and fiscal climate that will encourage the developement of smaller fields. The UKOOA has performed a technical study to describe and to quantify the changing opportunities and challenges that will characterize future oil and gas activity on the UKCS. The objective was to determine the likely range of future hydrocarbon production levels and to relate them to future reserve potential and to the level and pace of industry activity required for exploration, pace of industry activity required for exploration, appraisal, and development of new reserves. This study encompassed both oil and gas and used statistical techniques to evaluate the potential for future discoveries in mature regions. The techniques adopted, based on past exploration experience, enabled future discoverable quantities and field size distributions to be estimated. The emphasis was on the spectrum of potential UKCS opportunities. No attempt was made to forecast the extent of the commercial viability of discoveries, which depends on physical parameters, future prices, technology, and fiscal regime. In the absence of economic constraints, however, the potential production contribution from the various field sizes was investigated and is illustrated here. Note that the conclusions of this study, are not invalidated by the collapse in oil prices during the first half of 1986, just 1 year after the paper was first presented. Naturally, most operators' future exploration and oil development plans have been reduced or deferred and lowercost solutions are now being sought, particularly to develop the oil accumulations closer to existing production platforms with spare capacity. Thus, while the reserve platforms with spare capacity. Thus, while the reserve base remains unchanged, the pace of oil and gascondensate developments over the next few years is likely to be much slower than the selected scenario, at least until prices recover. Gas development has not been so severely affected, indeed, more U.K. gas is being developed in 1986 than at any time since the early 1970's. The production from incremental development of existing fields was not quantifiable from available data. Similarly, the potential of frontier areas was not included because insufficient exploration data were available within UKOOA to quantify the possible contribution from these areas. It was recognized that although these frontier areas will contribute some production, it is unlikely to be significant before the end of the century.

Analytical Method
In mid-1983, UKOOA members contributed to a confidential survey, enumerating all discoveries and describing their size and general location. The results of this survey are given in Table 1. The average size of the 33 fields contributing to the 13.3 × 10 bbl [2.1 × 10 m3] of oil, natural gas liquids (NGL), and condensate in production or under development was over 400X 10 bbl production or under development was over 400X 10 bbl [64 × 10 m3], whereas the average size of the other 70 discoveries was only 58 × 10 bbl [9×10 m3]. The average size of the 10 nonassociated gas fields in production or under development was 2.9 Tcf [82 × 10 9 M 3 production or under development was 2.9 Tcf [82 × 10 9 M 3 whereas the average size of the other 36 nonassociated gas discoveries was 0.7 Tcf 120 × 10 9 m3]. As would be expected, the larger oil and gas discoveries have been developed first, although, from the evidence of this survey, the decline in the size of oil discoveries is more pronounced than for gas discoveries. pronounced than for gas discoveries. JPT
p. 64