Abstract: A safety valve having a mono spring closure mechanism. The closure mechanism may be free of any spiral wound spring. The closure mechanism may include a spring having a beam which bends along its length to apply a biasing force to the closure member at its fully closed position and at its fully open position. The closure mechanism may include only a single spring, with the spring having at least two legs, the legs being joined to each other at an end of each leg, and each leg including at least one beam.

Abstract: System and method for cementing through a safety valve. A system includes a flow passage, closure mechanism, opening prong repeatedly displaceable to thereby repeatedly operate the closure mechanism open and closed, and a latching device initially maintaining the opening prong positioned isolating the closure mechanism from the flow passage, and releasing the latching device permits the opening prong to open and close the closure mechanism while it is exposed to the flow passage. A method includes the steps of: latching an opening prong so that a closure mechanism is open and is isolated from a flow passage; releasing the opening prong so that the closure mechanism is closed and is exposed to the flow passage; and displacing the opening prong to a position in which the closure mechanism is open and is exposed to the flow passage.

Abstract: A formation isolation valve for underbalanced drilling applications. A system for operating a formation isolation valve includes the valve interconnected in a casing string. An assembly displaces through the casing string, thereby causing the valve to open prior to the assembly reaching the valve. An operating system includes a well tool with an actuator positioned downhole. A device for causing the actuator to operate the well tool is also positioned downhole remote from the actuator. A method of operating a well tool includes the steps of: positioning the well tool in a well, the well tool including an actuator; positioning a power source for the actuator in the well; and at a downhole position remote from the actuator, causing the actuator to operate the well tool.

Abstract: A safety valve with extension springs. In a described embodiment, a valve for use in a subterranean well includes a closure member having open and closed positions. A structure displaces to cause the closure member to displace between the open and closed positions. A biasing device has a length which decreases as the structure displaces to cause the closure member to displace toward the closed position.

Abstract: Downhole mechanical or electrical equipment that possess, induce or supply large electromagnetic interference or magnetic fields are sometimes placed in subterranean wells, usually as part of or attached to wellbore tubulars. These magnetic fields can interfere with the efficient operation of some electronic, gyroscopic or magnetic well tools that pass by, through, near or adjacent to such downhole equipment. In general, a subterranean magnetic field protective shield apparatus is provided which reduces or substantially eliminates this magnetic field interference or enhances the operation of, or minimizes damage to, sensitive electronic or magnetic well tools. Such a subterranean magnetic field protective shield enhances the operation of other tools and protects other devices from adverse effects of magnetic fields stronger than the earth's magnetic field intensity.