SEA DRAUGEN LICENSE
In the Haltenbanken area, the first license (436 km/sup 2/ 107,750 ac) was issued in 1980 by 1983, after the issue of four more licenses adjacent to the first, two gas/condensate fields had been discovered, Midgard and Tyrihans (total gas reserves = 5 tcf).
These purchases, particularly important in more » the early concession rounds, have largely financed the government's investment. Oil companies that wished to apply for a license first had to purchase selected, relevant state seismic. Together they acquired nearly 21,000 km of data from More in the south, through Haltenbanken, to Traenabanken in the north. For the first eleven years from 1969, only the Norwegian authorities and Statoil shot seismic surveys in the region. « lessįor 20 years, oil and gas exploration on the Mid-Norway continental shelf has been a process of evaluation carefully orchestrated by the government, leading to today's proven reserves of 2.3 million bbl of oil and 12.4 tcf of gas. Pending a gas offtake solution for the Haltenbanken region, produced associated gas will initially be reinjected into a water-bearing structure in the western part of the field. In view of the low intrinsic reservoir energy, the development will involve pressure support from water injection with oil offtake via crestal producers. Intraformational shales are notably absent, and more » vertical and lateral communication within the hydrostatically pressured reservoir are believed to be excellent. Fault offsets may, however, provide localized communication paths. The sandbar development is generally confined to within the areal closure and the reservoir is separated from the main aquifer by a 2-30 m thick shale. Thus, with a limited number of relatively widely spaced wells, a reservoir geologic model was developed as a basis for numerical simulation. Detailed sedimentologic studies combined with high-quality seismic data, enabled the optimization of appraisal well locations and subsequent delineation of sandbar geometry. It was recognized early in the appraisal phase that the reservoir sands could be of limited lateral extent. The reservoir comprises a high-quality coarsening-upward sand sequence interpreted as a single offshore sandbar encased in marine shales.
The low-relief anticlinal structure, with a vertical closure of 45 m, has an areal extent of 20 by 6 km and contains approximately 1,000 million standard bbl of undersaturated oil. Five further appraisal wells were drilled between 1984 and early 1986 and a development plan was finalized during 1987. The Draugen field in the Haltenbanken area on the mid-Norwegian shelf was discovered by Norske Shell in 1984 when the exploration well 6407/9-1 encountered oil in a previously unknown Upper Jurassic sand.
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