Abstract: A seal assembly includes an outer member defining a bore and an inner member received in the bore of the outer member and one of the outer member and the inner member defining a shoulder portion. An inner circular cross-section metallic ring member and an outer circular cross-section metallic ring member are disposed between the outer member and inner member and against the shoulder portion. A wedge member engages the inner circular cross-section metallic ring member and the outer circular cross-section metallic ring member for applying an axial force against each of the inner and outer circular cross-section metallic ring members in a direction toward the shoulder portion and for applying a radially outer force against the outer circular cross-section metallic ring member and for applying a radially inner force against the inner circular cross-section metallic ring member.

Abstract: A seal assembly includes an outer member defining a bore and an inner member received in the bore of the outer member and one of the outer member and the inner member defining a shoulder portion. An inner circular cross-section metallic ring member and an outer circular cross-section metallic ring member are disposed between the outer member and inner member and against the shoulder portion. A wedge member engages the inner circular cross-section metallic ring member and the outer circular cross-section metallic ring member for applying an axial force against each of the inner and outer circular cross-section metallic ring members in a direction toward the shoulder portion and for applying a radially outer force against the outer circular cross-section metallic ring member and for applying a radially inner force against the inner circular cross-section metallic ring member.

Abstract: A centralizer having bow springs in a retracted position to facilitate passage through a restriction. After passing through the restriction, the bow springs may be expanded to support a casing. In one embodiment, the bow springs may be expanded using a movable sleeve.

Abstract: A seal assembly for sealing between an inner surface of a bore and an outer surface of a mandrel includes at least one annular seal including a channel disposed in an axial end thereof with a locking shoulder facing axially away from an opening end of the channel. The annular seal has an innermost diameter that is smaller than an outer diameter of the mandrel and has an outermost diameter that is larger than an inner diameter of the bore. An annular locking ring includes a locking member at a first axial end that is received in the channel of the at least one annular seal and having a ledge portion engaged with the locking shoulder of the annular seal. The ledge portion includes at least one slot extending axially there through.

Abstract: A method of running casing in a dual gradient system includes lowering a casing into a low density fluid region and allowing the low density fluid to enter the casing; releasing a plug into the casing; supplying a high density fluid behind the plug; and lowering the casing into a high density fluid region until target depth is reached.

Abstract: A centralizer having bow springs in a retracted position to facilitate passage through a restriction. After passing through the restriction, the bow springs may be expanded to support a casing. In one embodiment, the bow springs may be expanded using a movable sleeve.

Abstract: A method of running casing in a dual gradient system includes lowering a casing into a low density fluid region and allowing the low density fluid to enter the casing; releasing a plug into the casing; supplying a high density fluid behind the plug; and lowering the casing into a high density fluid region until target depth is reached.

Abstract: A method and apparatus for a pressure relief valve assembly. The valve assembly may be coupled to one or more casings and/or tubular members to control fluid communication therebetween. The valve assembly is a one-way valve assembly that relieves pressure within an annulus formed between adjacent casings and/or tubular members to prevent burst or collapse of the casings and/or tubular members. The valve assembly is resettable downhole.

Abstract: A pressure relief valve assembly may be coupled to one or more casings and/or tubular members to control fluid communication therebetween. The valve assembly is a one-way valve assembly that relieves pressure within an annulus formed between adjacent casings and/or tubular members to prevent burst or collapse of the casings and/or tubular members. In one embodiment, the valve assembly includes a tubular body having a port for fluid communication between an exterior of the valve assembly and an interior of the valve assembly; a chamber formed in a wall of the tubular body, the chamber in fluid communication with the port; and a closure member disposed in the chamber and configured to control fluid communication through the port in response to a pressure differential.

Abstract: The present invention relates to apparatus and methods for remotely actuating a downhole tool. In one aspect, the present invention provides an apparatus for activating a downhole tool in a wellbore, the downhole tool having an actuated and unactuated positions. The apparatus includes an actuator for operating the downhole tool between the actuated and unactuated positions; a controller for activating the actuator; and a sensor for detecting a condition in the wellbore, wherein the detected condition is transmitted to the controller, thereby causing the actuator to operate the downhole tool. In one embodiment, conditions in the wellbore are generated at the surface, which is later detected downhole. These conditions include changes in pressure, temperature, vibration, or flow rate. In another embodiment, a fiber optic signal may be transmitted downhole to the sensor. In another embodiment still, a radio frequency tag is dropped into the wellbore for detection by the sensor.

Abstract: Methods and apparatus are provided for reducing surge pressure while running casing into a wellbore. The apparatus includes a running string for running casing having a diverter tool therein. The diverter tool has one or more bypass ports between its upper and lower end which are normally closed. In operation, the diverter tool is automatically cycled between the open and closed positions of the bypass ports during a casing running operation. A pressure event inside the diverter tool deactivates the cyclic opening and closing function of the bypass port.

Abstract: The present invention relates to apparatus and methods for remotely actuating a downhole tool. In one aspect, the present invention provides an apparatus for activating a downhole tool in a wellbore, the downhole tool having an actuated and unactuated positions. The apparatus includes an actuator for operating the downhole tool between the actuated and unactuated positions; a controller for activating the actuator; and a sensor for detecting a condition in the wellbore, wherein the detected condition is transmitted to the controller, thereby causing the actuator to operate the downhole tool. In one embodiment, conditions in the wellbore are generated at the surface, which is later detected downhole. These conditions include changes in pressure, temperature, vibration, or flow rate. In another embodiment, a fiber optic signal may be transmitted downhole to the sensor. In another embodiment still, a radio frequency tag is dropped into the wellbore for detection by the sensor.

Abstract: The present invention relates to apparatus and methods for remotely actuating a downhole tool. In one aspect, the present invention provides an apparatus for activating a downhole tool in a wellbore, the downhole tool having an actuated and unactuated positions. The apparatus includes an actuator for operating the downhole tool between the actuated and unactuated positions; a controller for activating the actuator; and a sensor for detecting a condition in the wellbore, wherein the detected condition is transmitted to the controller, thereby causing the actuator to operate the downhole tool. In one embodiment, conditions in the wellbore are generated at the surface, which is later detected downhole. These conditions include changes in pressure, temperature, vibration, or flow rate. In another embodiment, a fiber optic signal may be transmitted downhole to the sensor. In another embodiment still, a radio frequency tag is dropped into the wellbore for detection by the sensor.

Abstract: Methods and apparatus are provided for reducing surge pressure while running casing into a wellbore. The apparatus includes a running string for running casing having a diverter tool therein. The diverter tool has one or more bypass ports between its upper and lower end which are normally closed. In operation, the diverter tool is automatically cycled between the open and closed positions of the bypass ports during a casing running operation. A pressure event inside the diverter tool deactivates the cyclic opening and closing function of the bypass port.

Abstract: The present invention relates to apparatus and methods for remotely actuating a downhole tool. In one aspect, the present invention provides an apparatus for activating a downhole tool in a wellbore, the downhole tool having an actuated and unactuated positions. The apparatus includes an actuator for operating the downhole tool between the actuated and unactuated positions; a controller for activating the actuator; and a sensor for detecting a condition in the wellbore, wherein the detected condition is transmitted to the controller, thereby causing the actuator to operate the downhole tool. In one embodiment, conditions in the wellbore are generated at the surface, which is later detected downhole. These conditions include changes in pressure, temperature, vibration, or flow rate. In another embodiment, a fiber optic signal may be transmitted downhole to the sensor. In another embodiment still, a radio frequency tag is dropped into the wellbore for detection by the sensor.