This invention relates to a method for recovering a tubular structure (3) from a well (1), wherein a so-called free point is defined as the location where the tubular structure is stuck in the well. The method comprising providing a downhole tool string comprising a pipe-severing tool and an upper part of the downhole tool string; lowering the downhole tool string into the tubular structure to release the free pipe. Before the step of triggering the pipe-severing tool to sever the tubular structure, the method includes releasing the pipe-severing tool and subsequent withdrawing the upper part, of the downhole tool string away from the free point towards the surface over at least a predefined distance. The invention relates to a downhole tool string for use in such method.

A patching construction method using a hydraulic variable-grade expansion tool for blocking during is provided, which includes a conversion joint, a supporting central pipe, a supporting ring, an expansion pipe, pressure gradient piston subs, double female thread connection subs, T-shaped limiting subs, a tapered centering sub, double male thread central shafts, split supporting subs, an expansion cone, a piston sub with male and female threads, a T-shaped ball compressor, a lower U-shaped pressing sleeve, a ball-seat fixing sleeve, a reciprocating spring, a sealing ball seat, a sealing ball, a tapered guide sub, etc. A patching construction method using a hydraulic variable-grade expansion tool for blocking during, omits the conventional expansion cone sealing manner, and designs a variable pressure gradient expansion tool, so that achieves the objectives of low pressure, large expansion force and reliable sealing, avoids drilling out bottom sealing joint, and reduces the risk of expansion failure.

The present invention relates to a downhole method for providing a zonal isolation at a predetermined position in an annulus between a wall of a borehole and a well tubular metal structure having a longitudinal extension in an existing well, comprising inserting a downhole tool in the well tubular metal structure, positioning the downhole tool opposite the predetermined position, separating a first section of the well tubular metal structure from a second section of the well tubular metal structure by machining into and along a circumference of the well tubular metal structure, inserting an unexpanded annular barrier between the first section and the second section, and expanding the annular barrier for providing zonal isolation at the predetermined position.

A safety valve for extraction wells, configured to be installed on a well head and to enclose a tubular material portion inserted inside the well. The tubular material is internally hollow to contain and transport substances extracted from the well. The safety valve includes: a central hole through which the tubular material passes; a blocking system configured to keep the tubular material to be cut fixed with respect to the safety valve; a cutting and closing group configured to cut and close the well under certain operative conditions; and a sealing mechanism configured to effect watertight closing of the well, after the cutting. The cutting and closing group includes a hole saw housed in a respective chamber of the cutting and closing group, rotated by a motorized actuator, and configured to move in a controlled mode along a substantially orthogonal direction with respect to a development direction of the well.

A safety valve for extraction wells, configured to be installed on a well head and to enclose a tubular material portion inserted inside the well. The tubular material is internally hollow to contain and transport substances extracted from the well. The safety valve includes: a central hole through which the tubular material passes; a blocking system configured to keep the tubular material to be cut fixed with respect to the safety valve; a cutting and closing group configured to cut and close the well under certain operative conditions; and a sealing mechanism configured to effect watertight closing of the well, after the cutting. The cutting and closing group includes a hole saw housed in a respective chamber of the cutting and closing group, rotated by a motorized actuator, and configured to move in a controlled mode along a substantially orthogonal direction with respect to a development direction of the well.

A safety valve assembly for extradition of hydrocarbons includes a valve body including a passage duct, configured to be traversed by a production and/or drilling line. The valve body includes housings for a punch and counter-punch, arranged diametrically opposite to one another with a common longitudinal axis substantially perpendicular to the longitudinal axis of the valve. The punch slides linearly in a controlled manner in the housing along the axis which intersects the longitudinal axis of the pipe, and the counter-punch slides linearly in a controlled manner in the housing along the axis which intersects the longitudinal axis of the pipe. The punch and counter-punch are configured to allow the counter-punch to slidingly receive the punch in its interior to create two different shearing planes. The counter-punch includes a hollow part to slidingly receive the section of tubular material and the punch, in the linear movement during the shearing operation.

A safety valve assembly for extradition of hydrocarbons includes a valve body including a passage duct, configured to be traversed by a production and/or drilling line. The valve body includes housings for a punch and counter-punch, arranged diametrically opposite to one another with a common longitudinal axis substantially perpendicular to the longitudinal axis of the valve. The punch slides linearly in a controlled manner in the housing along the axis which intersects the longitudinal axis of the pipe, and the counter-punch slides linearly in a controlled manner in the housing along the axis which intersects the longitudinal axis of the pipe. The punch and counter-punch are configured to allow the counter-punch to slidingly receive the punch in its interior to create two different shearing planes. The counter-punch includes a hollow part to slidingly receive the section of tubular material and the punch, in the linear movement during the shearing operation.

A valve assembly for controlling fluid communication along a well tubular that includes hydraulically operated valve that includes a valve member movable between open and closed positions, and a hydraulic actuator for moving the valve member; a control system for selectively controlling the flow of hydraulic fluid to and from the actuator; a vent chamber for selectively receiving hydraulic fluid exhausted from the actuator when the valve member is moved to its closed position; and a vent conduit for selectively receiving hydraulic fluid exhausted from the actuator when the valve member is moved to its closed position. The control system has a first valve closing state in which the vent chamber is isolated from the actuator. The control system has a second valve closing state in which fluid exhausted from the actuator during movement of the valve member to its closed position is vented into the vent chamber.

A valve assembly for controlling fluid communication along a well tubular that includes hydraulically operated valve that includes a valve member movable between open and closed positions, and a hydraulic actuator for moving the valve member; a control system for selectively controlling the flow of hydraulic fluid to and from the actuator; a vent chamber for selectively receiving hydraulic fluid exhausted from the actuator when the valve member is moved to its closed position; and a vent conduit for selectively receiving hydraulic fluid exhausted from the actuator when the valve member is moved to its closed position. The control system has a first valve closing state in which the vent chamber is isolated from the actuator. The control system has a second valve closing state in which fluid exhausted from the actuator during movement of the valve member to its closed position is vented into the vent chamber.

A device for cutting and plugging underwater pipes, the device includes a frame with one or more clamps for securing the device to the pipe. Attached to the frame is an arm having a first end and a second end. The first end is attached to an actuation element that in combination with a support bar can pivot and extend the arm. A motor is attached to the second end of the arm. A saw blade and pipe plug is concentrically mounted to the motor. The motor powers the saw blade to cut the pipe transversely. The arm then positions the pipe plug concentric with the cut pipe, and in combination with rotation of the motor, plugs the cut pipe with the pipe plug.