Dispositif pour la commande automatique du remplissage des cuvelages de puits, notamment de puits de pétrole

摘要

766,232. Well apparatus. BAKER OIL TOOLS, INC. March 21, 1955 [April 2, 1954], No. 8166/55. Class 85. A valve controls the filling of a well conduit whereby the conduit can be filled to a predetermined height while running in after which cement slurry &c. can be pumped down the conduit when the valve functions as a non- return valve to prevent fluid flowing up through the conduit. A casing 10, having a cementitious plug 14, is secured to the bottom of a well conduit B. A valve guide member 28 is supported by the hub 25 of a spider 24 having ribs 26. The guide member is prevented from upward movement by the engagement of a shoulder 39 with a frangible flange 38 on the hub 32 of an upper spider 33 which itself is held from upward movement by a lower valve seat 35. The upper end 40 of the guide member 28 is formed as a piston and slides in a bore 39, containing air, of a valve head 43. While the conduit is being lowered in the borehole fluid flows up through the spiders 24,33 lifting the valve head 43 off its lower seat 35 and passing up through the conduit B, the valve head 43 being prevented from engaging an upper seat 20 by a pin 45 on the valve head engaging the bottom of the piston 40. The upper surface area of the valve head 43 exposed to downward fluid pressure is greater than the lower surface area exposed to upward fluid pressure so that when the ratio of the head of fluid in the conduit to that outside the conduit in the borehole is the same as the ratio of said surface areas the valve head 43 closes on its lower seat 35. Pressure is applied to the fluid in the conduit until the flange 38 shears off and the spider 33, valve seat 35 and valve head 43 move downwards, see Fig. 4, the head being held off the lower seat 35 by the piston 40. Cement slurry can now be pumped down through the conduit. After cementing, upward flow of fluid through the conduit is prevented by the head 43 being pushed upwards on to the upper valve seat 20, the pin 45 engaging the piston 40. and raising the guide member 28 with it. (See Fig. 5 not shown). The internal mechanism of the valve may be made of readily drillable materials such as magnesium alloy, aluminium alloy, cast iron or the like. Specification 714,910 is referred to.