Not applicable.
1. Field of the Invention
The invention relates generally to the field of wellbore safety and control valves.
More specifically, the invention relates to wellbore safety and control valves that can be installed in a failed wellbore valve and operated remotely.
2. Background Art
Wellbore valves, such as subsurface safety valves, are used for controlling flow within a well tubing string suspended within a wellbore. Typically, valves of this type include a valve member that is pivotally or rotatably mounted within the bore of a tubular body disposed within the well tubing string for movement between open and closed positions. The valve member is urged by a spring to its closed position, but is typically arranged to be moved to the open position in response to the supply of hydraulic fluid pressure from a remote source at the Earth's surface. The hydraulic fluid pressure acts on a piston forming part of or associated with the valve member. Ordinarily, the valve member is arranged to close automatically under the force of the spring in response to the exhaust of such hydraulic fluid pressure, for example, in the event of failure of a monitored condition in or about the well.
Other types of valves may be remotely operable, such as by applying pressure signals to a fluid annulus between a wellbore casing and a coaxial tubing string. Such valves are described, for example, in U.S. Pat. No. 4,796,699 issued to Upchruch et al. and include a power supply associated with a valve operator proximate the valve in the wellbore, a signal receiver and a controller that causes the valve operator to open or close the valve in response to signals transmitted from the surface.
Many such valves are tubing safety valves wherein the body of the valve is disposed within the well tubing string for controlling flow therethrough. Such valves may be of a type in which the valve body is retrievable from within the tubing string, or in which the body is connected as part of the tubing string, i.e., tubing mounted. Typically, such a valve is a flapper pivotally mounted in the bore of the valve body and arranged to be moved to the open position by a flow tube with which an hydraulic piston cooperates to move the flow tube within the bore. Thus, the supply of hydraulic fluid pressure lowers the flow tube to force the flapper to the open position. A spring opposingly acts on the piston to raise the flow tube and thus permit the flapper to close upon the exhaust of hydraulic fluid pressure on the piston.
U.S. Pat. No. 3,799,258 shows a typical tubing mounted valve of this type wherein the piston is an annular piston disposed about the flow tube within an annular pressure chamber between the flow tube and valve body. The piston urged to its closed position, enabling the flapper to close, by means of a coil spring compressed between the valve body and the flow tube. However, when valves of this type are installed at great depths, it is difficult for a coil or similar metal spring of acceptable size and strength to overcome the hydrostatic head of the hydraulic fluid in the control line leading to the pressure chamber, and thus raise the flow tube to permit the flapper to close.
In the event of failure of the control line and/or the valve actuator, the valve will close. Valve closure causes the well to cease producing fluid until which time the well can be repaired. Such loss of production can be costly. Further, repairing a failed wellbore valve in a well that is capable of producing fluid is difficult and expensive Typically the well must be “killed” by pumping fluid having sufficient density to cause the producing subsurface formations to stop moving fluid into the wellbore, or a “snubbing unit” or similar device must be used that enables the wellbore production tubing to be removed while the wellbore has substantial pressure at the surface.
There exists a need for a replacement and/or repair valve that can be inserted into a defective valve body and operated remotely.
A remotely operable wellbore valve system according to one aspect of the invention includes a valve configured to be coupled to a wellbore conduit and to selectively close the conduit. The valve is disposed in a valve body configured to open an existing wellbore valve by longitudinal motion therethrough and to sealingly engage an interior of the existing wellbore valve. The system includes a valve actuator and a signal receiver in communication with the valve actuator. The signal receiver is configured to detect command signals transmitted from the Earth's surface and to cause the actuator to operate the valve in response to the detected command signals
Other aspects and advantages of the invention will be apparent from the following description and the appended claims.
U.S. Pat. No. 6,899,178 issued to Tubel et al. discloses an acoustic wireless communication device for transmitting signals from a wellbore to the Earth's surface. The principle of the device disclosed in the Tubel et al. '178 patent may be used to transmit control signals from the Earth's surface to a valve controller disposed in the wellbore. The acoustic based wireless communication device is able to transmit data to the surface through the wellbore tubing string, while also transmitting data through the fluids in the wellbore.
An example of a system used to transmit command or control signals from a wellhead (typically at the Earth's surface) is shown in
A wireless receiver or transceiver unit (see
Using any of the foregoing devices, for example, other commands that can be sent from the surface to a device in the wellbore include commands to maintain power supply to a device, shut off power supply to a device, regulate power levels in the device, transmit diagnostics, etc. The receiver portion of the wireless system or a wireline device can be hung off in the wellbore using standard type wireline locks landed in landing nipples, or hung off by a slips type arrangement.
In one example the wellbore device is a remotely controllable wellbore valve that can be used to temporarily, or permanently, replace the function of a hydraulically operated subsurface safety valve. Referring to
A lower end 30C of the valve body 30A may be suitably shaped to cause the flapper 24 to open. Flow ports 36 may be provided at a selected position along the length of the valve body 30A to enable fluid flow through the upper part of the valve body 30A while maintaining a suitably sealed enclosure for batteries and control electronics 38. Such electronics 38 may include an acoustic transducer (not shown separately) for receiving acoustic commands from the system at the surface, or, alternatively, may include an acoustic or electromagnetic transducer for communication with a sonde 42 moved through the tubing 16 using an armored electrical cable 40. A corresponding transducer 44 in the sonde 42 may provide one or two way signal communication between the sonde 42 and the valve system 30.
A valve flapper 34 is disposed in the valve body 30A such that upon receipt of a suitable command or otherwise as will be further explained, the electronics 38 will cause an actuator (not shown) to open or close the flapper 34.
The wireless communication system explained above with reference to
Referring again to
Example command configurations and valve system responses may include one or more of the following. When the valve system is in the open position, a “maintain valve in open position” signal can be transmitted to the system from the surface at selected time intervals, e.g., every 15 seconds. If the downhole valve system electronics (38 in
A possible advantage of a valve system configured as explained above is that if an accident occurs at the surface, or there is external electrical power failure or a failure within the wireless valve control unit (11 in
A valve system according to the above description can be retrofitted into wellbores where an hydraulically or electrically operated valve does not function due to failure in the control line or cable from the wellhead to the valve. It is also possible to install the wireless valve system as a primary subsurface safety valve in new wells.
While the invention has been described with respect to a limited number of embodiments, those skilled in the art, having benefit of this disclosure, will appreciate that other embodiments can be devised which do not depart from the scope of the invention as disclosed herein. Accordingly, the scope of the invention should be limited only by the attached claims.
Priority is claimed from U.S. Provisional Application No. 60/977,687 filed on Oct. 5, 2007.
Number | Date | Country | |
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60977687 | Oct 2007 | US |