Abstract: A plug for use in a wellbore, said plug (201; 301) having a body with an upstream end and a downstream end, characterized in that a major portion of the length of said body is hollow and open to the upstream end of said plug. A plug set for use in a wellbore, said plug set comprising a top plug and a bottom plug, characterized in that a major portion of the volume of said bottom plug is hollow and a major portion of the length of said top plug can be accommodated therein. A plug for use in a wellbore, said plug comprising a body and at least a first fin which is made of resilient material and which projects radially outwardly from said body to engage, in use, the inner wall of a tubular, characterized in that said first fin is segmented and is provided with means to inhibit liquid passing through the gaps between said segment. The body and fin(s) of the plug can be made as a one piece injection moulding.

Abstract: The invention relates to an apparatus and a method for launching plugs used in the construction of an oil or of gas well. There is provided an apparatus for launching a plug, said apparatus comprising a canister (4) connectable to a running string, a plug (6, 16) retained in said canister, and a tube (9, 13) having a bursting disk (37, 38), the arrangement being such that, in use, an increase in fluid pressure in said tube ruptures said bursting disk allowing an increase in fluid pressure above said plug to launch said plug. The apparatus is particularly suited to launching two, three or more plugs independently. There is also provided a method of launching a plug from a canister, which method comprises the steps of blocking a tube; increasing pressure in said tube above said blockage to a predetermined pressure at which a bursting disk in said tube ruptures allowing fluid pressure to increase above said plug and launches said plug.

Abstract: A new method for introducing wellbore cement into a wellbore shoe joint has been invented, the shoe joint having a hollow tubular body, the shoe joint containing an amount of wellbore fluid, the shoe joint disposed in a wellbore cementing system between a float shoe, guide shoe, or other flow apparatus beneath the shoe joint, and a hollow tubular member above the shoe joint, the hollow tubular member being a lower part of a wellbore tubular string of a plurality of tubular members (e.g., casing) extending from an earth surface down into a wellbore, the method including moving a wellbore wiper plug into the hollow tubular body of the shoe joint, moving the plug within the shoe joint to push wellbore fluid from the shoe joint and, in one aspect, debris in the fluid, the fluid flowing to the float shoe, guide shoe or other flow apparatus, flowing wellbore cement into the hollow tubular body of the shoe joint.

Abstract: A new wellbore cementing system has been developed which includes, in certain embodiments, a plug container with a flow diverter for diverting a portion of flowing fluid away from plugs in the plug container; a plug set system with internal sleeves or dart receivers with shearable parts for shearing to selectively release plugs--all in certain embodiments made of non-metal material and/or plastic; a swivel equalizer with internal valving to isolate a plug set (or any other item) from torque and to relieve pressure below the swivel equalizer; and unique burst tube systems for selectively controlling fluid flow and plug system operation. In one aspect a plug nose is tapered to correspond to a taper of a landing ring so that wedge-locking of the nose and ring effects desired non-rotation of the plug during drilling. In one aspect plug fin bending is facilitated by reducing plug body thickness so that an alternate fluid flow path is provided for cementing.

Abstract: A new fill valve for use in cementing operations in a wellbore extending down into the earth has been invented, the fill valve having a tubular housing having a valve seat, a valve member slidably mounted in said tubular housing, a spring for biasing said valve member towards a closed position, the valve member having a head engageable with the valve seat of the tubular housing to close the valve, selectively releasable apparatus for releasably maintaining the fill valve in an open position, the selectively releasable apparatus including a shear ring breakable in response to pressure thereon, a slider movably disposed in a slider housing mounted in the tubular housing, a lower end of the slider initially projecting down and out from the slider housing and abutting a top end of the valve member and preventing the valve member from moving, a top end of the slider abutting the shear ring, the slider prevented initially from moving by the shear ring, the slider movable in response to pressure of fluid in the well

Abstract: A new valve has been invented, in some aspects useful in wellbore operations and/or as a mud saver valve which valve has a body through which fluid is flowable, a valve seat connected in and to the body and through which fluid is flowable, a valve member positioned adjacent the valve seat and selectively movable to seat against the valve to close the valve to fluid flow and selectively movable away from the seat to open the valve to fluid flow, and at least one recess on the valve member for holding debris and thereby preventing the debris from inhibiting valve closure.

Abstract: A new wellbore cementing system has been developed which includes, in certain embodiments, a plug container with a flow diverter for diverting a portion of flowing fluid away from plugs in the plug container; a plug set system with internal sleeves or dart receivers with shearable parts for shearing to selectively release plugs--all in certain embodiments made of non-metal material and/or plastic; a swivel equalizer with internal valving to isolate a plug set (or any other item) from torque and to relieve pressure below the swivel equalizer; and unique burst tube systems for selectively controlling fluid flow and plug system operation.

Abstract: A new wellbore cementing system has been developed which includes, in certain embodiments, a plug container with a flow diverter for diverting a portion of flowing fluid away from plugs in the plug container; a plug set system with internal sleeves or dart receivers with shearable parts for shearing to selectively release plugs--all in certain embodiments made of non-metal material and/or plastic; a swivel equalizer with internal valving to isolate a plug set (or any other item) from torque and to relieve pressure below the swivel equalizer; and unique burst tube systems for selectively controlling fluid flow and plug system operation.

Abstract: A fill valve includes a tubular housing which accommodates a valve member which is biased toward a closed position by a light spring. The valve member includes a head and a tubular portion which is provided with two large windows. When the fill valve is open fluid flows freely through the tubular portion of the fill valve and out of the windows.

Abstract: A fill valve includes a tubular housing which accommodates a valve member which is biased toward a closed position by a light spring. The valve member includes a head and a tubular portion which is provided with two large windows. When the fill valve is open fluid flows freely through the tubular portion of the fill valve and out of the windows.

Abstract: A shoe for attachment to a length of casing for use in a wellbore comprises a body portion attachable to casing, and a nose portion rotatably mounted on the body portion. A casing string with a plurality of casing sections and such a shoe.

Abstract: A new cementing system has been developed which includes, in certain embodiments, a plug container with a flow diverter for diverting a portion of flowing fluid away from plugs in the plug container; a plug set system with internal sleeves or dart receivers with shearable parts for shearing to selectively release plugs--all in certain embodiments made of non-metal material and/or plastic; and a swivel equalizer with internal valving to isolate a plug set (or any other item) from torque and to relieve pressure below the swivel equalizer.

Abstract: A fill valve includes a tubular housing which accommodates a valve member which is biased toward a closed position by a light spring. The valve member includes a head and a tubular portion which is provided with two large windows. When the fill valve is open fluid flows freely through the tubular portion of the fill valve and out of the windows.

Abstract: A fill valve includes a tubular housing which accommodates a valve member which is biased toward a closed position by a light spring. The valve member includes a head and a tubular portion which is provided with two large windows. When the fill valve is open fluid flows freely through the tubular portion of the fill valve and out of the windows.

Abstract: An anti-rotation device for use in a well tool, for example a top plug or a bottom plug, has a tapered male member having a corrugated outer surface which can enter a corresponding recess in another well tool to inhibit relative rotation therebetween.

Abstract: A pneumatic type pipe-end protector pressurizable for clamping onto a pipe-end is manufactured by centering a containment ring supported by a filling duct in a casting mold, covering the filling inlet with a pneumatically expandable element attached to the ring maintaining the outer end of the filling duct in communication with the ambient atmosphere, and then introducing plastic into the casting mold for forming the protector body.

Abstract: A pipe-end protector has a unitary body (3) bored for accommodating the pipe-end (1) to be protected and having an interior cavity connected through a one-way valve and a filling duct (6) with an exteriorly accessible filling connection, a metal ring (4) preventing the outwards expansion of the body (3) made of an elastic and strong plastic material. The metal ring (4) is a closed ring completely embedded in the plastic and sufficiently flexible for following elastic deformation of the plastic body, the body portion (10) outside said ring (4) having a sufficient thickness for providing elastic thrust protection, an expansion cavity (8) being defined by the inner wall of the ring (4), the filling duct (6) being situated in a depression (7) formed in an end face (11) of the body (3).