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Table 5-2. Inclination and bearing of collaring and at approximately every 200 m of KFM06C,indicating the borehole deviation. Also the difference in absolute deviation between theMAXIBOR and FLEXIT systems is shown (see definition in text above).KFM06Cborehole length (m)Z (m)*Inclination andbearing (FLEXIT)Inclination andbearing (MAXIBOR)*Diff. in absolute deviationbetween FLEXIT and MAXIBOR0 4.09 –60.12°/26.07° –60.12°/26.07°201 –166.75 –56.24°/32.40° –55.98°/32.79° 1.65402 –329.75 –52.43°/45.83° –52.00°/45.64° 2.27600 –482.34 –49.54°/60.14° –49.02°/58.14° 3.78801 –631.97 –48.74°/64.55° –48.02°/63.08° 6.43972 –756.08 –45.62°/72.42° –44.80°/71.42° 10.181,000.91 –776.41 –44.86°/73.69° –44.80°/71.42° 10.73* Maxibor measurement is in use flagged in SICADA. ** Calculated values.5.4.10 Measurements of the length difference between the compresseddrilling pipe string and as extended by its own weightAll length values used for measurements in the borehole and of the drill core originate fromregistrations of the length of the drill pipe string. However, such registrations involve a smallerror depending on the gravitational stretching of the pipe string when hanging freely andthus exposed to its own weight. When the pipe string is lowered to the borehole bottom, andthe lifting force from the drill rig is set to zero, the pipe string will be resting on the boreholebottom and thus relieved from the previous load, and the stretching will cease. Instead, the loadfrom the pipe string will now cause compression, and to some extent bending of it.By measuring the length difference between these two conditions, it was hoped that the lengtherror could be determined for different lengths of the pipe string and for different inclinationsof the borehole. The practical difficulties and uncertainties in the results however turned outto be considerable. Therefore it is recommended that the length error is determined fromthe diagram in Figure 5-20, which is based on load tests performed in the laboratory by themanufacturer of the drill pipes.300250200Elongation (mm)180150100500100 200 300 400 500 600 700 800 900 1000 1100 1200Length (m)Figure 5-20. The diagram illustrates the elongation of the WL-76 drill pipe string when hangingin a vertical water filled borehole. Values from laboratory load tests of the drill pipes.46