GB471732A - Improvements in packing heads for wells - Google Patents

Abstract

471,732. Packing - heads for wells. HYDRIL CO. Dec. 5, 1935, No. 33787. Convention date, Nov. 19. [Class 85] [Also in Group XXVI] A packing-head for a well comprises a contractible packer disposed about the work and a packer contractor movable vertically relative thereto under external control, the contractor having a tapered surface engaging the packer with a wedging action to contract it about the work. A further packer may be provided adapted to actuate the packer if a sudden increase of well pressure occurs. In Fig. 1, a housing 23 on the well casing has differential bores 24, 25 connected by a doubletapered shoulder 26 and receives a head 27 with a depending sleeve 27b ; a rubber packer 34, with an annular groove 40 in its lower end, is connected by reinforcing cables 47 to a ring 45 held to sleeve 27b by balls 46. An internally tapered differential piston 44 fits the bores 24 25 and supports a floating piston 54 of larger area than the lower end of piston 44 ; keys 56 are provided so that the pistons are removable with the packer &c. Means such as screws 57 limit movement of the pistons and a position indicator 60 is provided. Fluid, which may be from the well, is admitted through pipe 96 to raise the pistons and compress the packer, or through pipe 97 to lower the pistons &c. To enable the device to act as a blow-out preventer, the piston 44 may carry a further packing 64 which raises the piston 44 automatically on increase of the well pressure. The packing 64 may comprise superposed rubber rings 68 loosely connected by pins 72 to staggered members of upper and lower sectional rings 70, 71, to allow passage of pipe couplings 43a ; alternatively, the packing 64 may comprise a rubber ring 78, Fig. 7, held between internally -tapered segmental rings 79, 80, centred by strips 188, or it may comprise a loosely held ring 81, Fig. 8, moulded round a perforated tube 84 and provided with a lip 85 with a tapered upper surface. In Fig. 10, the main packer is carried by a sleeve 102 rotating on ball bearings 103, 105, and provided with a sleeve 107 for driving connection to a non- circular stem 100. Two packing heads may be arranged one above the other and after a drill collar passes into the space between the heads, it may actuate a radially-movable member to close a switch to operate signalling means. In .Fig. 16, after a drill collar has passed up through lower packing head 146, it operates switch 148 and closes a circuit through solenoid 163a to act through rack 162a, and pinion 161a to reverse valve 154 and apply the packer in head 146 ; when the packer is fully applied, indicator rod 60, Fig. 1, closes switch 170a, Fig. 16, to energize solenoid 164 and, through rack 162 and pinion 161, reverse valve 153 to free the packer in upper head 145. After lifting the pipe, switch 168 is reversed and switch 173 closed to reverse the valves 153, 154 in turn through solenoids 164, 164a. Switch 173 is then again opened. Specifications 471,793, 471,794, and 471,795 are referred to.