{
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    "wlbNpdidWellbore" : 217,
    "wlbName" : "25/10-4",
    "wlbHistory" : "\r\n\r\n\u003cp\u003e\u003cb\u003eGeneral\u003c/b\u003e\u003c/p\u003e\r\n\r\n\u003cp\u003eThis well was drilled in two phases, a\r\nprimary well bore 25/10-4, and a re-entry well bore 25/10-4 R. The well was\r\ndrilled in the western part of the Balder Field in the North Sea. The primary\r\nobjective was to establish the presence of a thick accumulation of Paleocene\r\noil sand, and evaluate sand-shale distribution and reservoir quality. The top\r\nof the reservoir was anticipated to be at 1698 m subsea. As a secondary\r\nhigh-risk objective, the well was to be drilled to 2700 m to test for the\r\npresence of hydrocarbons in the Permian. This test was necessary as any\r\nhydrocarbons present could critically affect the design and location of a\r\npossible production platform.\u003c/p\u003e\r\n\r\n\u003cp\u003e\u003cb\u003eOperations and results\u003c/b\u003e\u003c/p\u003e\r\n\r\n\u003cp\u003eAppraisal well 25/10-4 was spudded with\r\nthe semi-submersible installation Glomar Biscay II on 8 December 1980 and\r\ndrilled to TD at 2348 m in the Late Permian Zechstein Group where the well was\r\nsuspended due at 18 January 1981 due to a pressing need for the rig to drill\r\nother Balder Field delineation wells, combined with unexpected delays in the\r\n25/10-4 well progress as a result of lost circulation. The re-entry commenced\r\non 29 May 1981 and deepened the well to 2550 m in a massive unconsolidated sand\r\nof Permian/ Carboniferous age. The top hole down to 30" casing depth at\r\n214 m was drilled with seawater. Below 214 m the well, including the re-entry\r\nwell, was drilled with seawater/gels/lignosulphonate.\u003c/p\u003e\r\n\r\n\u003cp\u003eThe main oil sand of Paleocene age was\r\nencountered between 1759.5 m and 1784.0 m. The net oil sand was 22 m thick. The\r\nTriassic section had several thin and oil-bearing sandstones not detected\r\nbefore in the area. A wire line FIT in one of these sands proved live oil. In\r\ntotal these sandstones made up 21 m net sand but the accumulation was\r\nconsidered insignificant. Cuttings from 2130 m (Early Jurassic) through Permian\r\nZechstein and the upper part of the Permian/Carboniferous unconsolidated\r\nsandstone contained traces/shows of hydrocarbons.\u003c/p\u003e",
    "wlbHistoryDateUpdated" : "2026-02-24T00:00:00"
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