Annulus mounted potential energy driven setting tool

This application is a continuation of U.S. patent application Ser. No. 13/029,266, filed on Feb. 17, 2011, and claims the benefit of priority from the aforementioned application.

The field of the invention is actuators and actuation methods for operating a subterranean tool and more particularly actuation of a tool disposed about a tubular without a wall opening in the tubular using potential energy in the actuator when running in.

Many operations in a subterranean borehole involve the setting of tools that are mounted outside of a tubular string. A common example is a packer or slips that can be used to seal an annular space or/and support a tubular string from another. Mechanical actuation techniques for such devices, which used applied or hydrostatic pressure to actuate a piston to drive slips up cones and compress sealing elements into a sealing position, involved openings in the tubular wall. These openings are considered potential leak paths that reduce reliability and are not desirable.

Alternative techniques were developed that accomplished the task of tool actuation without wall openings. These devices used annular fluid that was selectively admitted into the actuator tool housing and as a result of such fluid entry a reaction ensued that created pressure in the actuator housing to operate the tool. In one version the admission of water into a portion of the actuator allowed a material to be reacted to create hydrogen gas which was then used to drive a piston to set a tool such as a packer. Some examples of such tools that operate with the gas generation principle are U.S. Pat. No. 7,591,319 and US Publications 2007/0089911 and 2009/0038802.

These devices that had to generate pressure downhole were complicated and expensive. In some instances the available space was restricted for such devices limiting their feasibility. What is needed and provided by the present invention is an actuator that goes in the hole with stored potential energy that employs a variety of signaling techniques from the surface to actuate the tool and release the setting pressure/force. The preferred potential energy source is compressed gas. Those skilled in the art will further understand the invention from a review of the description of the preferred embodiment and the associated drawings while further appreciating that the full scope of the invention is to be determined by the appended claims.

An actuator and method for setting a subterranean tool uses an externally mounted actuator on a tubular string that is operably engaged to the tool to be actuated. At the desired location for actuation a signal is given to a valve assembly. The opening of the valve releases the pressurized compressible fluid against a floating piston. The piston drives viscous fluid ahead of itself through the now open valve that in turn drives an actuating piston whose movement sets the tool. The triggering mechanism to open the valve can be a variety of methods including an acoustic signal, a vibration signal, a change in magnetic field, or elastic deformation of the tubular wall adjacent the valve assembly.

FIG. 1 is the assembly in the “run in the hole” position; and

FIG. 2 is the assembly of FIG. 1 in the set position downhole after the trigger is actuated.

FIG. 1 illustrates a tubular string 10 run into a wellbore 12 that is preferably cased. The tool to be actuated 14 is illustrated schematically as a metal to metal and/or elastomer seal that can have slips for fixation to the outer wellbore tubular 12 when the actuation link 16 is caused to move axially. A cone 18 is used to urge the tool 14 radially into contact with the borehole or tubular 12 . The link 16 extends from housing 20 that is attached to the tubular string 10 . String 10 passes through the housing 20 to define an annular shape 22 that is charged at a predetermined pressure with a compressible fluid 24 . A floating piston 26 defines the annular volume 22 on one side and annular volume 28 on the opposite side. Annular volume 28 is filled with a viscous fluid such as light weight oil 30 . Valve body 32 has a remotely actuated valve 34 . In the closed position of valve 34 the oil 30 is contained in annular volume 28 . Annular volume 36 is defined between valve body 32 and actuation piston 38 . Movement of piston 38 moves the link 16 to actuate the tool 14 such as by moving it up the ramp 18 . Pistons 26 and 38 have outer peripheral seals against the housing 20 and inner seals against the tubing string 10 . Annular volume 40 can be enclosed with low or no pressure or depending on the installation depth it can be open to the annulus through a check valve 42 that lets fluid escape out of volume 40 as it gets smaller when the link 16 is moved. Link 16 is sealed at 44 to keep surrounding fluids out of volume 40 as the tool 14 is set with movement of the link 16 .

Opening valve 34 can be performed by an acoustic signal 46 that is illustrated schematically. Alternatively the valve 34 can be actuated with a dart 48 that passes close to valve 34 and has a field such as an electromagnetic or permanent magnet field that communicates with sensor 50 on the valve housing 32 . Another method to operate valve 34 is to elastically deform the wall of the tubular in string 10 adjacent a sensor in the housing 32 . A straddle tool having a pair of spaced seals to create an enclosed volume into which pressure is delivered to flex the wall of the tubular 10 is envisioned. Alternatively, a wireline tool can be lowered to communicate with the valve housing 32 using magnetic, radio, ultrasonic, acoustic or mechanical signals.

FIG. 2 shows the tool 14 set against the casing or wellbore or tubular 12 after the cement (not shown) has been circulated and placed downhole but before it has cured. The opening of valve 34 has allowed the fluid 24 to expand the chamber 22 and displace the oil 30 from chamber 28 and into chamber 36 . As a result piston 38 is displaced setting the tool 14 . While the pistons 26 and 38 are shown as annular pistons they can also be rod pistons. Piston 26 can be eliminated so that the opening of valve 34 can employ the compressible fluid directly to move the piston 38 that is connected to the link or links 16 . The movement of the piston 38 is preferably axial but it can be rotational or a combination of the two when properly guided in its movements for setting the tool 14 . Although it is preferred to set the tool 14 as quickly as possible the rate at which it sets can be controlled with the size of the passage 54 that leads to and away from valve 34 . While using light oil 30 is preferred other relatively low viscosity fluids down to water can be used. The use of the piston 26 allows compensation for thermally induced pressure buildup in the compressible fluid 24 triggered by the temperature of the surrounding well fluids. Apart from the various signals mentioned above for opening the valve 34 , other triggers are possible although their use is less optimal than the techniques already discussed. The valve 34 can be triggered with time, temperature or proximity to devices carried by the string 10 that communicate in a variety of forms with the sensors and processor in the housing 32 . While the preferred tool 14 is an annular barrier other tools can be actuated outside the tubular 10 while avoiding having openings through its walls. Some of those tools can be anchors or centralizers, for example. While compressed gas as the potential energy source is preferred other options such as using a shape memory alloy or a bistable material or a mechanical spring such as a coiled spring or a Belleville washer stack to trigger piston 38 are other options.

The above description is illustrative of the preferred embodiment and many modifications may be made by those skilled in the art without departing from the invention whose scope is to be determined from the literal and equivalent scope of the claims below.