GB640285A - Improvements in or relating to a well tool - Google Patents

Abstract

640,285. Well-cementing tools. TAYLOR, C. C., and McGAFFEY, E. W. Sept. 15, 1947, No. 25180. Convention date, Feb. 1, 1946. [Class 85] A well-cementing tool comprises a tubular body 4 secured to a string of drill pipe 3, the body carrying spaced packers 5, 6 defining in conjunction with the well casing 2 a chamber 7. The tubular body is sealed off from the drill pipe by a partition 8 and the pressure in the casing above and below the packers is equalized during entry of the tool since fluid flow can occur through ports 9, 10 which lead into a passage through the tubular body. The drill string is connected by a pipe 11 to the chamber 7 whilst a pipe 15 connects the chamber to a port opening into the well casing space below the packers. The ports 10, 14 are controlled by a sleeve valve 20. During the lowering of the tool, the ports 10, 14 are open and the pressure equalized in the drill stem, chamber 7 and the upper and lower casing space. On the tool reaching a level slightly below the area of the perforated casing it is raised a short distance so that the valve 20 closes the ports 10, 14 and grout is pumped down the drill pipe, through pipe 11 and out through the perforations in the casing. To clean the tool after the operation fluid can be pumped down the casing, through port 9 and out of the spring-biassed valve 27, up past packer 6 into chamber 7 and thence up the drill pipe by way of passage 12. Alternatively, the tool can be lowered so that ports 10 and 14 are opened and fluid pumped down the drill pipe into the chamber 7, through pipe 55 into the lower casing space and back to the upper casing space by ports 9, 10. To prevent the tool from being forced upwards, slips are provided, the slip-expanding means being carried on a mandrel 35 secured between the drill pipe and the body, the mandrel being forced downwards to a slip-expanding position by pressure fluid in the drill pipe acting on a piston 55 carried by the mandrel.