in bbl. (b) Volume of the drill collars in bbl (c) Number of pump cycles required to pump surface mud to the bit(duplex pump, 6 in liners, 2.5 in rods, 16 i strokes, pumping at 85 % volumetric efficiency). (d) Displacement of drillpipes in bbl/ ft (e) Displacement of drill collars in bbl/ft.
Fig: 1
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