E - Fixed Constructions – 21 – B
Patent
E - Fixed Constructions
21
B
E21B 34/10 (2006.01) E21B 34/06 (2006.01) E21B 49/08 (2006.01)
Patent
CA 2053245
Following completion of the testing procedure applied to a newly drilled oil well using a mechanism of the annulus pressure-responsive type, it is necessary safely to "shut down" the test tools, and then to remove the test string from the packer assembly and pull it to the surface. It is desirable for the high pressure reference gas in the tool to be vented before the string reaches the well head. It is also an advantage if there be incorporated within the test string some means of isolating the upper portion of the tubing thereof, and of subsequently providing a route for communication between this tubing and the annulus, so that tubing-contained well liquid above the test string can then be circulated out of the tubing before it is raised to the surface. The invention provides apparatus for the venting and isolation procedures just described, this apparatus permitting those operations to be carried out as an automatic sequence, following the application of a single actuating pressure pulse to the annulus. For the venting of the reference gas, the invention suggests pressure release apparatus having two spaced pistons (7, 11) located at opposite ends of a chamber (10) filled with that gas and blocking both a gas vent (17) to annulus and a hydraulic liquid passageway (22: to further up the test string), the pistons being held together by a shear pin (13) until the application of a predetermined pressure (higher than the gas reference pressure) at the outside ends of those pistons causes the pin to shear, allowing sequential movement of the two pistons towards each other, with the effect of firstly opening the gas vent to annulus, and secondly opening the passageway (22) to a chamber (24) of hydraulic liquid. The hydraulic liquid pressure within this passageway then causes actuation of ball valve apparatus for isolating the upper section of tubing. This apparatus is in the form of a ball-valve-driving piston (39) blocking another passageway (40) for hydraulic liquid, which piston is: forced to move under the influence of the pressure, breaking a restraining shear pin (44) as it does so, and closing the ball valve while opening this other hydraulic liquid passageway, permitting transfer of hydraulic pressure to apparatus for venting the contents of the tubing to annulus. Finally, this venting apparatus contains a longitudinally-movable sleeve member (54) the position of which determines whether or not flow is permitted, via vent ports (55, 56), from the test string tubing to the annulus.
Buchanan Robert Donald
Edwards Jeffrey Charles
Johns Ray
Expro North Sea Limited
Gowling Lafleur Henderson Llp
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