Patent GB-862699-A (GB)
Title: Well completion and well packer apparatus and methods of selectively manipulating a plurality of well packers
IPC: E21B33/12
Filed: 1959-08-06
Abstract: 862,699. Oil wells. BROWN, C. C. Aug. 6, 1959, No. 26989/59. Class 85. In the completion of a multiple produc. tion zone well, a number of unset packers and a number of tubing strings are lowered into the well to locate the packers in positions to separate different production zones and to communicate each of the tubing strings with a different production zone, a well head is installed to suspend the strings, and the packers are set to separate the production zones. As described, two packers A, B are used with two tubing strings 14, 10 to produce from zones F, F<SP>1</SP>. The packers comprise rubber or like packing elements which are compressed axially by hydraulic means and are, in consequence, expanded radially to seal against the casing P. The upper packer A is shown in Figs. 5a, 5b, joined end to end, and receives the tubing strings 10, 14, the latter being attachable to the packer by a bayonet-like coupling 26, 27. The packers A, B are lowered into the well by the string 10 and the string 12 connected thereto, and the string 14, is or may be lowered subsequently into place, being guided into the bore 15<SP>b</SP> by an inclined cupped upper surface 15e of the packer A. The tube 10 extends through the body 15 and rubber packing element 18 of the packer A and ends in a coarse preferably left-handed screw 22<SP>a</SP> on which screws a release coupling 22 secured to the tubing string 12. A ring 20 rests upon the coupling 22 and supports the packing 18 which is compressed axially by a piston 16 which is actuated by pumped pressure from the tube 14 passing through ports 25<SP>a</SP>. A plug 35 is dropped or lowered through the tubing string 14 to close the open end during actuation of the piston 16. After a shear pin 30 is ruptured, the downward motion of the piston, seals the packing 18 against the well casing P, and, when the pressure is removed from the piston, the tendency of the packing to expand longitudinally actuates slips 31 to grip the tube 10 and hold the packing in its sealing condition. The packer is released for removal by turning the tubing string 10 to unscrew the tube 10 from the coupling 22, which carries the slips 31 upwardly relatively to the ring 20 and permits axial extension and radial contraction of the packing 18. When the tube 10 is completely unscrewed, the packer A may be removed from the well, leaving the tube 12 to be manipulated, as described below, by a fishing tool for release of the packer B which is shown in Figs. 5c, 5d, 5e joined end to end. The packer consists of a mandrel 40 connected by a coupling 41 to the tubing string 12, a piston 65 carrying non-return slips 71 for compressing the packing 55, and a slip carrier 48 and slips 48a for gripping the casing P to provide a stationary abutment for the packing 55 to hold it against the downward force of the piston 65, the carrier 48 being screwed on coarse, preferably left-handed threads 46 on the mandrel 40. When the packer B is correctly positioned, a plug 45 is dropped or lowered into the string 12 to seal the open end thereof. Pump pressure passes through the port 40b, depresses the piston 65 and shears the pin 70 so that the sleeve 67, slip operator 66, collar 56 which confines the upper part of the packing 55, and inner sleeve 57 all descend with the piston. The downward thrust on the packing 55 forces down a ring 52 to which is secured a tubular body 51 having its lower end 50 formed to expand the slips 48<SP>a</SP>, so that the bottom stop ring 52 of the packing is held against downward movement by the tendency of the packing to expand longitudinally and, when the piston pressure is released, the same tendency maintains the slips 71 in gripping engagement with the mandrel 40. The packer B is released for removal by turning the string 12 with the fishing tool whereby the screw connection 46 raises the mandrel in the cage 48 which diminishes and eventually eliminates the longitudinal compression of the packing which operates the slips 91, 48<SP>a</SP>. An additional slip 80, with a longitudinal gripping edge 80<SP>a</SP>, may be fitted to eliminate the tendency of the cage 48 to rotate during the release movements. Slips 60 may also be vulcanized into the packing member 55. The connection between the string 10 and the string 12 may be modified, so that the packers are both released by rotating the string 10, the use of fishing tools being thus eliminated, and the construction in Fig. 5a may be modified in that the port 25<SP>a</SP> is, when the packer is set and the pump pressure stopped, not in communication with the space at the top of the piston 16, the deposition of sediment in that space being thereby avoided.