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5.4.3 Registration of drilling parametersA selection of results from drilling parameter registration is presented in diagrams below.As regards the complete dataset of drilling parameters, it is referred to SICADA, where dataare traceable by the activity plan number.Drill bit position versus timeFigure 5-5 illustrates how drilling proceeded versus time. Generally, drilling ran 24 hours aday from Monday to Thursday with a weekend stop from Thursday night to Monday morning.Figure 5-5 serves as a basis for Figure 5-3, to which it should be compared.Penetration rateThe penetration rate, see Figure 5-6, was in average almost the same as during drilling ofKFM01A /5/. Initially, the penetration rate started with 12–13 cm/min, but fell successivelyback to c. 10 cm/min, corresponding to the increasing frictional resistance of the return waterflow, which is conducted in the narrow gap between the borehole wall and the pipe string.In addition, KFM06C has a large borehole deviation and this reduces the retrieval of drillcuttings and slows down the penetration rate, in spite of the fact that the borehole diameterwas increased from c. 76 mm in KFM01A to 77.3 mm in KFM06C.Feed forceIn Figure 5-7 the feed force is plotted versus borehole length. As the software for the steeringsystem had been upgraded, resulting in a better control of the drilling parameters, the level offeed force when drilling KFM06C was lower compared with the feed force registered whendrilling the previous boreholes KFM01A to KFM04A, but higher than in KFM06A, situatednearby at drill site DS6.1000KFM06C900800700Bit position [m]600500400300200100004-27 05-02 7 12 17 22 27 06-01 6 11 16 21 26 month-daySTART :05/04/26 06:00:00 INTERVAL: >= 1 Hour STOP :05/06/30 17:59:59Figure 5-5. Drill bit positioning in KFM06C versus time.34