Abstract: A downhole tool comprises a hollow body having a wall and a port in the wall, and a closing sleeve movable relative to the body to open and close the port. A seal is provided between the body and the sleeve and is configured to hold differential pressure. An isolation member may be deployed in the tool to isolate the seal from differential pressure and close the port. The isolation member may be deployed following initiation of a tool activation process, a successful outcome of the process being translating the closing sleeve and closing the port, and positioning the seal to hold a differential pressure. If it is detected that the outcome has not been achieved, the isolation member is deployed to isolate the seal from differential pressure and close the port.

Abstract: A downhole cleaning tool (40) adapted for location in bore-lining tubing (22). The tool (40) comprises a tubular body (42) defining an internal bore (48), at least one radially extending cleaning blade (92), and an external axially extending bypass flute (96, 98, 100, 102). The body further defines a fluid flow path from the internal bore (48) to at least one elongated jetting slot (94) extending along an outer surface of the blade (92).

Abstract: Downhole apparatus (30) comprises: a tubular body (42) for incorporation in a tubing string (24); a float valve (30) mounted in the body (42) and operable to prevent flow up though the body; and a float valve retainer (38) maintaining the float valve (30) in an inoperable configuration and permitting flow up through the body (42), the retainer (38) comprising a flow restriction (80) to permit creation of a pressure differential across the restriction (80) and reconfiguring of the retainer (38) to permit operation of the float valve (30). The flow restriction (80) has a retracted configuration and an extended configuration to permit creation of the pressure differential, the flow restriction (80) maintaining the retracted configuration until exposed to a selected absolute pressure.

Abstract: A downhole tool comprises a hollow body having a wall and a port in the wall, and a closing sleeve movable relative to the body to open and close the port. A seal is provided between the body and the sleeve and is configured to hold differential pressure. An isolation member may be deployed in the tool to isolate the seal from differential pressure and close the port. The isolation member may be deployed following initiation of a tool activation process, a successful outcome of the process being translating the closing sleeve and closing the port, and positioning the seal to hold a differential pressure. If it is detected that the outcome has not been achieved, the isolation member is deployed to isolate the seal from differential pressure and close the port.

Abstract: A downhole tool comprises a hollow body having a wall and a port in the wall, and a closing sleeve movable relative to the body to open and close the port. A seal is provided between the body and the sleeve and is configured to hold differential pressure. An isolation member may be deployed in the tool to isolate the seal from differential pressure and close the port. The isolation member may be deployed following initiation of a tool activation process, a successful outcome of the process being translating the closing sleeve and closing the port, and positioning the seal to hold a differential pressure. If it is detected that the outcome has not been achieved, the isolation member is deployed to isolate the seal from differential pressure and close the port.

Abstract: Downhole apparatus (30) comprises: a tubular body (42) for incorporation in a tubing string (24); a float valve (30) mounted in the body (42) and operable to prevent flow up though the body; and a float valve retainer (38) maintaining the float valve (30) in an inoperable configuration and permitting flow up through the body (42), the retainer (38) comprising a flow restriction (80) to permit creation of a pressure differential across the restriction (80) and reconfiguring of the retainer (38) to permit operation of the float valve (30). The flow restriction (80) has a retracted configuration and an extended configuration to permit creation of the pressure differential, the flow restriction (80) maintaining the retracted configuration until exposed to a selected absolute pressure.

Abstract: A downhole tool comprises a hollow body having a wall and a port in the wall, and a closing sleeve movable relative to the body to open and close the port. A seal is provided between the body and the sleeve and is configured to hold differential pressure. An isolation member may be deployed in the tool to isolate the seal from differential pressure and close the port. The isolation member may be deployed following initiation of a tool activation process, a successful outcome of the process being translating the closing sleeve and closing the port, and positioning the seal to hold a differential pressure. If it is detected that the outcome has not been achieved, the isolation member is deployed to isolate the seal from differential pressure and close the port.

Abstract: A method of severing a drill-string comprises reducing the load bearing cross-sectional area of the neck of a connection. The reduction in the area of the neck may be achieved using a precisely located flow-actuated cutter. The cutter may be pumped into the string to land on a seat above the connection. A bypass valve may be provided below the connection to facilitate fluid circulation.

Abstract: A downhole tool comprises a body having a fluid inlet and a fluid outlet and configured to accelerate fluid flowing along a fluid flow path from the inlet to the outlet. The fluid outlet is configured to provide a radially directed and substantially circumferentially continuous stream of fluid. The stream of fluid may be used to clean or cut downhole tubing, such as casing.

Abstract: An activating device is provided for location in downhole tubing. The device defines an activation profile which is initially maintained at a larger diameter than a tubing seat, such that the device may land on and be held up by the seat. The profile may be subsequently reconfigured to radially retract, allowing the device to pass through the seat.

Abstract: A downhole tool comprises a hollow body having a wall and a port in the wall, and a closing sleeve movable relative to the body to open and close the port. A seal is provided between the body and the sleeve and is configured to hold differential pressure. An isolation member may be deployed in the tool to isolate the seal from differential pressure and close the port. The isolation member may be deployed following initiation of a tool activation process, a successful outcome of the process being translating the closing sleeve and closing the port, and positioning the seal to hold a differential pressure. If it is detected that the outcome has not been achieved, the isolation member is deployed to isolate the seal from differential pressure and close the port.

Abstract: A downhole tool comprises a hollow body having a wall and a port in the wall,and a closing sleeve movable relative to the body to open and close the port. A seal is provided between the body and the sleeve and is configured to hold differential pressure. An isolation member may be deployed in the tool to isolate the seal from differential pressure and close the port. The isolation member may be deployed following initiation of a tool activation process, a successful outcome of the process being translating the closing sleeve and closing the port, and positioning the seal to hold a differential pressure. If it is detected that the outcome has not been achieved, the isolation member is deployed to isolate the seal from differential pressure and close the port.

Abstract: Drill string check valve apparatus comprises a tubular body and a flapper valve mounted in the body with a flapper movable between an open position and a closed position. An axially extending valve retainer is also mounted in the body and is translatable from a running position to a drilling position. In the running position the valve retainer extends through the valve to maintain the flapper in the open position. In the drilling position the valve retainer permits the flapper to move to the closed position to prevent flow up through the body.

Abstract: Downhole apparatus comprises first and second tools for location in a tubing string. The first tool has a first seat of a first diameter and the second tool has a second seat of a second diameter larger than the first diameter. First and second activating devices are provided for use in activating the respective first and second tools. The first activating device includes a first activating profile having an extended diameter larger than the first diameter and smaller than the second diameter and a retracted diameter smaller than the first diameter. The second activating device includes a second activating profile having an extended diameter larger than the second diameter and a retracted diameter smaller than the first diameter.

Abstract: A downhole tool comprises a body having a fluid inlet and a fluid outlet and configured to accelerate fluid flowing along a fluid flow path from the inlet to the outlet. The fluid outlet is configured to provide a radially directed and substantially circumferentially continuous stream of fluid. The stream of fluid may be used to clean or cut downhole tubing, such as casing.

Abstract: A method of severing a drill-string comprises reducing the load bearing cross-sectional area of the neck of a connection. The reduction in the area of the neck may be achieved using a precisely located flow-actuated cutter. The cutter may be pumped into the string to land on a seat above the connection. A bypass valve may be provided below the connection to facilitate fluid circulation.

Abstract: An activating device is provided for location in downhole tubing. The device defines an activation profile which is initially maintained at a larger diameter than a tubing seat, such that the device may land on and be held up by the seat. The profile may be subsequently reconfigured to radially retract, allowing the device to pass through the seat.

Abstract: Drill string check valve apparatus comprises a tubular body and a flapper valve mounted in the body with a flapper movable between an open position and a closed position. An axially extending valve retainer is also mounted in the body and is translatable from a running position to a drilling position. In the running position the valve retainer extends through the valve to maintain the flapper in the open position. In the drilling position the valve retainer permits the flapper to move to the closed position to prevent flow up through the body.

Abstract: A method for facilitating a downhole cutting operation comprises providing a drilling fluid conditioning device in a surface portion of a tubular string providing mounting for a cutting tool on a downhole portion of the string. Initially, drilling fluid is circulated through the conditioning device and the tubular string to condition the drilling fluid. The drilling fluid conditioning device is then removed from the string and the conditioned drilling fluid circulated through the tubular string and the cutting tool.

Abstract: Downhole apparatus comprises first and second tools for location in a tubing string. The first tool has a first seat of a first diameter and the second tool has a second seat of a second diameter larger than the first diameter. First and second activating devices are provided for use in activating the respective first and second tools. The first activating device includes a first activating profile having an extended diameter larger than the first diameter and smaller than the second diameter and a retracted diameter smaller than the first diameter. The second activating device includes a second activating profile having an extended diameter larger than the second diameter and a retracted diameter smaller than the first diameter.