Patent GB-1483072-A (GB)
Title: Dual hydraulically actuated oil well packer
IPC: E21B33/1295
Filed: 1974-09-19
Abstract: 1483072 Wells DRESSER INDUSTRIES INC 19 Sept 1974 [2 Nov 1973] 40884/74 Heading E1F  A dual string well packer includes two tubular mandrels 7, 8 fixed to an upper head assembly 9, anchor slip means, a packer assembly 3, and hydraulic actuating means 6 for setting the packer in the well casing. The head assembly 9 includes threads 10c for connection to a primary string (not shown) and a releasable connector 14 for connection to a secondary string, the connector 14 including seals 17 and spring mounted lugs 16c which engage projection 9a in the head 9. In the first embodiment the packer includes upper and lower anchor slips 4, 5 (Figs. 3A, 3B) which consist of tubular members slidably mounted on the mandrels 7, 8 and arranged for pivotal movement so that gripping teeth on opposite sides and ends of the members can engage the well casing. The packer assembly 3 is slidably mounted on the mandrels 7, 8 between the slips 4, 5 and consists of rigid end plates 31, 33 and resilient elements 32, The hydraulic actuating means 6 consists of a cylinder 62 fixed to the mandrels 7, 8 and a piston 61 initially fixed by shear pins 68. The packer is set by blocking the secondary mandrel 8, e.g. by ball 20, and supplying fluid under pressure to mandrel 8, the fluid passing into cylinder 62 via ports 80. Pins 68 are then sheared and piston 61 moves upwardly to tilt the slips 4, 5 to their casing engaging positions and to compress packer unit 3. The packer is locked in its set condition by spring loaded ratchet pins 65 (Fig. 5) mounted in piston 61 engaging ratchet teeth 8b (Fig. 2b) formed on mandrel 8. Ratchet pins 65 have reduced area shearable portions 65a to allow the packer to be released by pulling upwardly on the primary string to shear pins 65 and allow the piston 61 to move downwardly relative to mandrel 8. The slips 4, 5 are returned to their non engaging positions by spring 48a (Fig. 3A) and spring loaded flange 49a (Fig. 3B) respectively. In a modification (Fig. 19) the packer unit 3 is locked to the mandrel 8 by ratchet pistons 213, 214 mounted in the upper end plate 231 of packer (corresponding to end plate 31, Fig. 2B) engaging ratchet teeth on mandrel 208. The pistons 213, 214 are urged inwardly to their mandrel engaging positions by the pressure of fluid in the well bore below the packer unit, the fluid passing into the piston chambers 211b, 212b via pipes 206, 207 extending through the packer to its lower surface. In a second embodiment (Figs. 10B, 10C) the apparatus includes an upper head assembly 103, a packer assembly 104, a single anchor slip 105 and hydraulic actuating means 106. The actuating means 106 consists of a piston 160 fixed to the mandrels and a movable cylinder 161 which, when pressurised moved into engagement with the anchor slip 105 thereby rotating slip 105 and compressing packer 104. The packer 104 is locked in its compressed condition by a wedge slip assembly 144, 145 and the anchor slip 105 is locked in its tilted position by wedge slip assembly 162, 163. The packer is released by pulling upwardly on the primary string thus shearing pins (not shown) and allowing upward movement of the head assembly 103 relative to the mandrels, thereby permitting release of the packer. Reference has been directed by the comptroller to Specifications 1265868 and 1395014.