GB1301491A - - Google Patents

Abstract

1301491 Underwater wells ROCKWELL MFG CO 25 March 1970 [23 April 1969] 14386/70 Heading E1F An underwater well has a casing into which is set a hanger below the mudline, to enable control valves also to be set below the mudline to protect them e.g. from storms and sinking ships. The hanger 55 (Fig. 3B) has slips 57 extended to grip the casing by a setting cone 58 raised by fluid pressure applied to space 61; the setting cone is restrained by shear pins 65 until they are sheared when the fluid pressure is applied. Tubing strings 21, 22 are screwed into the hanger and are cemented in, and for this purpose, the hanger 55 has a cement returns passage 76. The hanger is inserted on a running tool (80, Fig. 3A not shown) having a sleeve (90) which surrounds the tool body (86) and holds in place a latch (84) connecting the tool to the hanger 55. The tool is screwed onto the end of handling strings which have flanges (105) so that when they are unscrewed from the tool body, they raise the sleeve (90) to release the latch, allowing the tool body, which is retained in the sleeve by a lost-motion device to be removed. The well is completed (Fig. 8) by means of a connector 150 also carrying a sleeve 160 which locks latches 182 holding the connector to the hanger 50. The sleeve is connected to pistons 200 which are raised when the connector is being run down the well to allow the latches to engage, and are lowered to lock the latches by pressure applied to both sides of the pistons (which are of unequal area) through lines 218, 219, from a riser 300. The risers 300, 301 contain valves 251, 252, and the riser 300 contains a nipple 304 adapted to receive a plug. If the valve 251 is open, a solid plug run into the nipple 304 allows pressure to be applied to the bottom only of the pistons 200 to disconnect the connector and risers from the hanger. If the valve 251 is closed, a plug is run down on tubing (Fig. 11, not shown) to allow the space above the pistons 200 to be vented while pressure is applied below the pistons. The wellhead may be located on a submerged platform (Fig. 1, not shown). For example, if the seabed is 1200 feet deep, the platform may be at 600 feet.