GB846859A - Well conduit anchoring apparatus - Google Patents

Abstract

846,859. Oil wells. BAKER OIL TOOLS Inc. May 15, 1959, No. 16733/59. Class 85. Apparatus for anchoring a pipe string in a well casing comprises a mandrel 10 incorporated in a string B by couplings 12, 14, slips 15 expansible radially on the mandrel, an expander 23 slidable on the mandrel, a piston 35 on the mandrel, a cylinder 32 connected to or integral with the expander slidable on the mandrel and piston, and means on the piston engageable with the cylinder to prevent a relative movement which would expand the slips when running in, but disengages the piston and cylinder when a sufficient fluid pressure differential is applied, which pressure differential effects the expansion of the slips. In Fig. 1, the apparatus is used above a tool D, e.g., a set-down type of packer. The slips 15 are slidable radially in T-sectioned slots 16 in a ring 17 slidable between the coupling 12 and a shoulder 27, and are slidable also in inclined T-sectioned splines 25 in the expander 23 which is connected to the ring 17 by springs 28 and guide pins 30. The piston 35 has spring arms 52, 46 with groove engaging heads 54, 45, the heads 54 restricting the upward movement of the piston by engagement with a flange 60, and the downward movement by the continued engagement of the cam faces of the head with the came face 56, the piston always being below the ports 37. The apparatus is lowered in the well with its parts in the Fig. 1 position. When the packer reaches the desired position, it is expanded by manipulation of the string B, and the pressure in the string is raised, e.g., for a formation fracturing operation, the pressure passing the ports 37 to the space 33. The piston 35 is forced down sufficiently to cam the heads 45 out of the groove 49, and the cylinder is free to rise. The slips 15 and ring 17 are lifted until the ring reaches the coupling 12, when the springs 28 become compressed and the slips are expanded. The increasing pressure tends to force the piston 35 downwards whereby the heads 54 are cammed outwardly by the face 56 until teeth 58 on the other sides of the arms 52 engage complementary grooves 59 in the cylinder wall. This engagement transmits upward fluid pressure thrust on the mandrel to the cylinder and expander to augment the gripping action of the slips. The heads 54 are passed into their operative position through slots in the flange 57 and are retained in position between the slots by a bolt head 63. When it is desired to remove or re-set the apparatus, the pressure is reduced and the teeth 58, 59 disengage, the springs 28 release the slips and push the separator down until the head 45 snaps into the groove 49. If the springs 28 fail to do this, an upward pull on the string will effect the release, this being initiated by a difference in the slopes of the cam face 56 and the teeth 59 which enables the teeth 59 to prevail over the cam 56 and force the head 54 inwardly to free the cylinder. In Fig. 6, the springs 28 are replaced by a spring 79 which bears between an inturned flange 70 on the cylinder skirt 31a and a ring 81 which encircles and locks a split ring 83 in a groove 84. The flange 70 is prevented from rising prematurely on the mandrel 10a by a split ring 71 having a cam engagement 74 with a groove, a cam face washer 78 transmitting the thrust of the spring to the ring 71 and tending to keep it in the groove. Pressure in the space 33a tends to raise the cylinder, but this is resisted until the ring 71 is cammed out of its groove, when the cylinder may rise against the much weaker resistance of the spring 79. The expander 23, slips 15 and ring 17 are raised until stopped by the coupling 12 when the slips are expanded, the increasing pressure in the space 33a forces down the piston 35a to cam out the arms 52a on the cam washer 57a whereby the teeth 58a on the arms engage the grooves 59a on the cylinder to transmit upward thrust on the mandrel to the slips. Release is effected by dropping the pressure, or if this fails, by pulling on the string. Fig. 8 shows a modification for locking against downward motion in the casing, the locking being effected by a pressure differential in the annulus H between the string and the casing. The apparatus is substantially the same as that shown in Fig. 6, except that it is inverted, and the spring split ring 71 is replaced by a split ring 105 which initially rests in a groove 106 and is dislodged therefrom by the pressure in the annulus H forcing down the cylinder member 70a, 31a. The piston 35b is pressed up by pressure entering at 111. The release is effected by reducing the pressure in the space H, thus allow the spring 110 to withdraw the slips, or failing this, by forcing down the string.