GB916328A - Well tools - Google Patents

Abstract

916,328. Oil wells. GRIMMER, G. G., and BOSTOCK, J. H. May 29, 1959 [Dec. 12. 1958], No. 18449/59. Class 85. A flow control device in a tubing string includes a valve means for controlling the flow into the string through a lateral port or ports, the valve means having a small port which is preliminarily aligned with the said lateral port to produce a gradual equalization of pressure between the inside and outside of the string before a main port is aligned with the lateral port to permit a full flow. This prevents a sudden change in internal pressure from injuring packings and blowing the running-tool up the string with consequent tangling of the wire. A number of control devices may be arranged at different levels and the running-tool passes through all the devices to open or close any or all of them. Figs. 3 and 4 when joined end to end show a flow control device arranged in a string 27, and a running tool 100 with its operating wire 149 to which the tool 100 is connected either way up by the screwed ends 147, 146. As shown, the tool is being used with abrupt shoulders 140 on outwardly expansible keys 118 facing upwardly to engage a shoulder 83 on a valve sleeve 70, to move the sleeve upwardly from closed to pressure equalizing and then to fully open position. If the tool were reversed, the shoulders 140 would engage an upwardly facing shoulder 73 on the valve sleeve 70 to move the valve downwardly to the closed position. The valve sleeve 70 is slidable in a nipple 22, 23, 24, incorporated by couplings 28 in the string 27, between the shoulders 93, 94. The sleeve 70 is clutched to the running tool 100 by the keys 118 being urged outwardly by springs 130 into either a top recess 82 or a bottom recess 72 in the sleeve, according to whether the sleeve is to be moved up or down. The sleeve 70 has small diameter pressure-applying ports 77 which are dished outwardly at 79 to present larger areas to the lateral ports 44 in the nipple when the sleeve is being moved up from the closed position, whereby, without increasing the flow area through the ports 77, the external pressure is applied to the underside of an O-ring 65, the equalization of pressure across the ring relieving the pressure of the ring on the moving sleeve and thus minimizing wear. When the pressure in the string has sufficiently risen, the sleeve 70 is further raised to align the main flow ports 75 with the ports 44, the equalized internal pressure being applied to the packing 56 to reduce the pressure difference across the packing and to minimize wear thereon as the ports 75 pass therethrough. The sleeve is releasably locked in closed, pressure equalizing and main flow positions by slotting the walls of the upper key recess 82 at 86, the strips 87 between the slots having external protuberances 88 which, in view of the springiness of the strips 87, may spring into or be cammed out of grooves 90, 91, 92 corresponding to the three desired positions of the sleeve. The keys 118 are carried by a sleeve 107 which is secured to flanges 114, 122 having fingers 115, 126 which return the keys by engaging, with play for the expansion, in recesses 124 at the ends of the keys. The sleeve 107 is mounted on member 102 between shoulders 111, 110, but is prevented from sliding thereon by a shear pin 127. The member 103 is formed with a sleeve part 106 with a bevelled cam edge which remains inoperative whilst the pin 127 is intact. If it is desired to raise the sleeve 70 from the closed position, the running tool 100 is lowered, the cam faces 135 on the keys 118 pushing the keys inwardly as they pass obstructions. When the keys are aligned with the upper recess 82, they move out into the recess and the shoulder 140 engages under the shoulder 83 permitting the sleeve to be pulled up first to the pressure equalizing position and then to the main flow position. Further upward force on the tool brings the cam faces 143 on the keys against the cam face 34 on the nipple and the keys 118 are forced inwardly allowing the tool 100 to be withdrawn from the well. If the sleeve 70 is to be moved down to closed position, the tool 100 and the operations are reversed. When a number of flow control devices are in the tubing string, the tool 100 is passed down to the device which it is required to operate. If the valve sleeve 70 sticks at a position between fully open and fully closed, the cam means 34 or 35 on the nipple will not function to cam the keys 118 inwardly to permit the tool to be retrieved. In this event, a tug or downward jar, according to the disposition of the tool 100, will shear the pin 127 and will bring the cam edge of the part 106 against the cam ends of the keys, push the keys inwardly and retain them inwardly whilst the tool is retrieved. The key formation may be modified by dispensing with the part of the shoulder 142 which engages the cam 34 or 35 in which case the tool is used for opening a valve sleeve, or a number of valve sleeves below the uppermost flow control device, and the pin 127 is always sheared to permit ultimate retrieval of the tool.