GB950031A - Borehole drilling system - Google Patents

Abstract

950,031. Boring earth &c. JERSEY PRODUCTION RESEARCH CO. April 6, 1962 [May 1, 1961], No. 13430/62. Heading E1F. In a well boring apparatus members engage the wall of the well and apply an upward thrust thereto which thrust is reacted by the bit. A drill string 12 (Fig. 1) carries an arbor 14 which in turn carries bit 18. Rotatably mounted on the arbor is a housing 22 which has ports 28 containing rams 30 bonded to the wall of the ports by elastic collars 32. The outer faces 36 of the rams are inclined and slidably carry wedges 34. Drilling fluid from the arbor bore 56 may flow through ducts 64, 66 to urge the rams outwardly so that the wedges engage the wall with an upward thrust, and fluid from the inner face of the rams may flow through duct 62 to discharge into the well. In the position of the arbor shown the wedges of thrust units 60B, 60D, 60F, 60H are in engagement with the well wall, but as the string and arbor are rotated through 180 degrees these wedges are retracted and the wedges of units 60A, 60C, 60E, 60G, 60J are engaged with the wall. During rotation of the arbor and bit and supply of drilling fluid the continuous upward thrust on the wall developed by the wedges forces the arbor and bit downwardly to continue boring the well. In the modification shown in Fig. 5 the housing 90 is rotated with the arbor 84 by contact between friction plates 120, 122 mounted on the arbor and housing respectively. Gaseous or liquid fluid flows from the arbor bore 86 through duct 106 into annulus 102 above a piston 98 on the arbor to force resiliently mounted shoes 112 on the housing into engagement with the well wall and to bring the plates 120, 122 into engagement. The rotation of the arbor rotates the housing so that runners 116 on the shoes force the housing and bit downwardly. The bit may include means to reciprocate it in response to the flow of drilling fluid or the rotation of the string.