GB606077A - Well packers - Google Patents

Abstract

606,077. Well packers. McGAFFEY, E. W., and TAYLOR, C. C. Jan. 10, 1946, No. 889. Convention date, Jan. 30, 1945. [Class 85] In a well-packing tool the pressure of the entrapped fluid below the tool, instead of opposing the weight of the drill string is used to exert a downward force, so assisting the expansion of the slips. The tool comprises a body 2 containing a mandrel 4, which has a limited freedom of movement in both axial and radial directions. Relative axial movement between the mandrel and the body will cause the slips 11 to expand and grip the well casing 3, a lost motion connection 15 being provided between the mandrel and the slip head 13. The lower portion of the tool carries the packer means 31, 32 and consists of two chambers 42, 43 in which move pistons 38, 40, attached to the mandrel. In lowering the tool the mandrel is locked in position with respect to the body by a pin 23, so that the slips are withdrawn in the bowl 9, whilst the pressures above and below the tool are equalized by a byepass formed by an opening 46, chamber 43 and opening 45. When the desired depth is reached, the mandrel is unlocked by rotating it, and it then falls a short distance expanding the slips and closing the byepass. The packing means operate when the pressure below the tool is increased and this pressure acts on the top of piston 40 and on the underside of piston 38. The pressure on the other sides of the pistons is that acting above the tool, it acting through the passage 46, chamber 43 and passage 47. Because piston 40 is larger than piston 38 the resultant upthrust due to the fluid below the tool is diminished. Specification 600,341 is referred to.