1. Field of Invention
The invention is directed to sealing devices for isolating an annulus of an open-hole or cased oil, gas, and/or water wellbore and, in particular, to electronically set and retrievable sealing devices for use in open-hole formations that are capable of being electronically inflated and deflated.
2. Description of Art
Packers for isolating intervals and/or sealing the annulus of wellbores are known in the art. For example, some packers include an expandable elastomeric sealing element such as a rubber casing or balloon. These types of packers expand and, thus, seal to the inner wall surface of a wellbore by pumping a fluid into the rubber casing to expand the rubber casing into contact with the wellbore.
Some of these types of packers also include a swellable material within the rubber casing so that the swellable material, and not the fluid pressure itself, inflates the rubber casing. In these packers, the swellable material is contacted by hydraulic fluid or other fluid so that the swellable materials absorb the fluid and expand. In one type of these packers, for example, hydraulic fluid is pumped down a string of tubing having the packer secured thereto. The hydraulic fluid travels down the bore of the string of tubing and through a port that is in fluid communication with an inner cavity of the rubber casing. Swellable materials disposed within the rubber casing are contacted by the hydraulic fluid. As a result, the swellable materials absorb the fluid and expand. As the swellable materials expand and hydraulic fluid is pumped into the rubber casing, the rubber casing expands to seal the wellbore. After expansion, hydraulic fluid pressure is decreased and the rubber casing remains held in the expanded position solely by the swellable materials having absorbed the fluid.
Other packers are formed of an elastomeric material that is compressed or otherwise forced into the inner wall surface of the wellbore such as by expanding casing or axially compressing the elastomeric material that is disposed along an outer wall surface of the packer assembly.
Broadly, the sealing devices disclosed herein comprise an expandable sealing element that is inflated by a fluid being pumped into the expandable sealing element to set the sealing device in an open-hole wellbore. Thereafter, the fluid can be released from the expandable sealing element to deflate the expandable sealing element allowing the sealing device to be retrieved from the wellbore or to allow fluid to travel from outside of the zone previously isolated by the inflated expandable sealing element into the zone previously isolated by the inflated expandable sealing element. The expandable sealing element can be inflated electronically by a pump device that is capable of forcing fluid into the expandable sealing element and can be deflated by the same pump or by or in conjunction with another device such as a second pump, a one-way solenoid actuated valve, and the like.
The inflation and deflation of the expandable sealing element is controlled by an electronics package disposed on, adjacent to, or in close proximity of the sealing device. In one particular embodiment, the electronics package includes an electronic communication line in electronic communication with a downhole power supply and communications interface, and a surface control device such as a computer. A motor, motor encoder, and microcontroller operatively associated with a pump and a pump position encoder can also be included as part of the electronics package. In specific embodiments, multiple sealing devices can be located along a single string, each with its own electronics package. In these specific embodiments, control systems at the surface can address and choose which sealing device to operate, independent of the other sealing device(s).
While the invention will be described in connection with the preferred embodiments, it will be understood that it is not intended to limit the invention to that embodiment. On the contrary, it is intended to cover all alternatives, modifications, and equivalents, as may be included within the spirit and scope of the invention as defined by the appended claims.
Referring now to the Figures,
Referring now to
Disposed on mandrel outer wall surface 31 is expandable sealing element 40. Expandable sealing element 40 includes sealing element outer wall surface 41, and sealing element inner wall surface 42 defining sealing element chamber 43. Expandable sealing element 40 can be formed out of any material known in the art, including but not limited to elastomeric materials, rubber, and the like.
Although expandable sealing element 40 is shown in the particular embodiment of
In addition, in certain embodiment, expandable sealing element 40 is expanded by pumping cement or other fluid down the casing and is compatible with ongoing cementing operations. Thus, expandable sealing element 40 can provide reliable zonal isolation in cemented or non-cemented completions and can be used in conjunction with liners or long-string casing.
Sealing element chamber 43 is in selective fluid communication with mandrel port 33 by electronically activated pump 50. Pump 50 is preferably a positive displacement pump such as those known in the art. In certain embodiments, pump 50 is reversible. Preferably, pump 50 allows full control of inflation and deflation of expandable sealing element 40. All variations of pump 50 are known in the art.
In the embodiment of
In the embodiment of
To facilitate the action of pump 50, and to facilitate holding pump 50 in a desired position such as to keep expandable sealing element 40 in a set position (
In embodiments containing motor 55, the motor controller is responsible for receiving specific revolutions per minute (RPM) commands from microcontroller 58. The RPM commands are converted by the motor controller into motor driving signals that are sent to the electric motor inputs of motor 55. The motor controller operatively associated with motor 55 receives position information feedback from motor position encoder 56. This feedback allows precise closed loop control of the RPMs of motor 55 and, therefore, the inflation rate.
Also operatively associated with at least pump 50, but can also be operatively associated with one or more of power source 54, pump position encoder 61, motor 55, or motor position encoder 56 is microcontroller 58. Microcontroller 58 can be any microcontroller known in the art that is capable of being programmed to be controlled by surface processing unit 19, either actively or passively. In active control, surface processing unit 19 manually instructs microcontroller 58 to activate or deactivate pump 50. In passive control, microcontroller 58 is preprogrammed to activate or deactivate pump 50 at predetermine circumstances such as pressure. In certain embodiments, microcontroller 58 is programmed with sealing device specific identifying information so that each sealing device 20 disposed on a tool or work string is addressable. That is, each sealing device 20 can be controlled and, thus, inflated or deflated, separately from any other sealing device 20 disposed on the same tool or work string. In such embodiments, microcontroller 58 listens for commands sent to its tool address and turns on or off pump 50 accordingly. In addition, microcontroller 58 can be programmed with a desired pressure of expandable sealing element 40 (received from surface processing unit 19) and will electronically activate motor 55 to drive pump 50 to run until the desired pressure is reached. A pressure sensor (not shown) can be included to monitor the pressure within sealing element chamber 43 to turn-off pump 50 when the desired pressure is reached. Thus, using the pressure sensor for closed loop control, microcontroller 58 sends commands to pump 50. In embodiments having electric motor 55, microcontroller 58 sends RPM commands to the motor controller to turn on or turn off motor 55 and, thus, turn on or turn off pump 50. As a result, the pressure within sealing element chamber 43 can be precisely controlled.
Pump 50, motor 55, motor position encoder 56, and microcontroller 58 are in electronic communication with surface processing unit 19 through electronic communication line 18. As noted above, electronic communication line 18 can be a tubing encapsulated conductor (“TEC”) or any other electronic communications line known in the art. One suitable electronic control line and its arrangement for communication with downhole tools is disclosed and described in U.S. Pat. No. 6,173,788 issued to Lembcke, et al. which is hereby incorporated by reference herein in its entirety. In addition, the electronic communication system for controlling pump 50 and, if present, motor 55, motor position encoder 56, and microcontroller 58 can be any communication system known in the art. One suitable electronic communication system and its arrangement for control of downhole tools and operations is disclosed and described in U.S. Pat. No. 6,798,350 issued to Maxit, et al. which is hereby incorporated by reference herein in its entirety.
In the embodiment of
In the embodiment of
In operation, a sealing device such as a packer described above with respect to
To facilitate activation of the pump, in some embodiments a microcontroller and/or a motor are operatively associated with the pump. In addition, a pressure sensor can also be operatively associated with the pump. In these embodiments, the motor causes the pump to flow the fluid into the sealing element chamber, the microcontroller activates and controls the RPM of the motor, and the pressure sensor detects the pressure created within the sealing element chamber and relays this information to the microcontroller. When a predetermined pressure that is programmed in the microcontroller is reached, the microcontroller shuts off the motor.
Continuous monitoring of the current pressure inside sealing element chamber 43 allows any changes to be detected which would indicate that the pressure within the sealing element chamber is leaking. If such a situation occurs, then the motor should be reactivated to pump additional fluid into the sealing element chamber.
In certain embodiments, the microcontroller is programmed with predetermined parameters such that the microcontroller performs the operation of monitoring the orientation of the motor shaft. In these embodiments, if the motor shaft moves past a predetermined position, e.g., 1-5% off from its position when the motor is turned off, the microcontroller automatically turns the motor on so that the pump can flow additional fluid into the sealing element chamber. Thus, the microcontroller facilitates ensuring that the desired pressure remains in the sealing element chamber. In a similar fashion, the pump position encoder can be monitored and any changes in position outside a threshold would cause the motor and pump to be activated.
As persons skilled in the art will recognize, the microcontroller can be programmed and reprogrammed as desired or necessary by an operator operating the surface processing unit. Similarly, the surface processing unit and the software installed thereon can be modified as desired or necessary to facilitate performance of the inflation of the expandable sealing element to the desired pressure, and maintaining the expandable sealing element at the desired inflated pressure.
As a result of inflation of the expandable sealing element, a seal is created between the outer wall surface of the expandable sealing element and a sealing surface disposed as an inner wall surface of the open-hole wellbore, e.g., on the formation itself, or on an inner wall surface of a cased wellbore. As described above, because inflation of the expandable sealing element is controlled by the pump, the pump can be held in a fixed orientation to maintain the expandable sealing element in the inflated or set position.
Thereafter, if desired, the pump can be activated by sending an electronic signal through the electronic control line to the pump to reverse direction. Alternatively, the electronic signal can be sent to the microcontroller. As a result, the pump is activated to cause fluid within the sealing element chamber to be flowed out of the sealing element chamber, either into the bore of the tool or work string containing the sealing device, or into the wellbore annulus. Thus, the pump actively causes deflation of the expandable sealing element. Deflation of the expandable sealing element can be monitored by the motor, motor position encoder, pump position encoder, pressure sensor and/or microcontroller in a similar manner as during inflation. For example, the pressure sensor can be operatively associated with the microcontroller which is programmed with a predetermined shut-off pressure at which the microcontroller sends an electronic signal to the motor or pump to stop the pump from operating.
After deflation of the expandable sealing element, the sealing device can be re-located within the wellbore by moving the tool or work string upward or downward within the wellbore and the process of inflation repeated. Alternatively, the sealing device can be removed or retrieved from the wellbore.
In other alternative methods, the sealing device can be deflated to allow fluid communication between two zones of the wellbore that were previously isolated by the sealing device. For example, in an embodiment in which two or more sealing devices are included in a work or tool string, and both sealing devices are inflated to create an upper isolated zone and a lower isolated zone, the lower sealing device can be deflated to allow the upper and lower isolated zones to be placed in fluid communication with each other. Such a situation may be desirable where a well completion including fluid flow control valve disposed in the tool or work string below the lower sealing device fails and fluids desired to be flowed out of the wellbore from the lower zone are trapped. In such a situation, the lower sealing device can be deflated to allow the trapped fluid to flow from the lower zone into the upper zone where a functioning fluid control valve can flow the previously trapped fluid through the tool or work string without the need for an intervention operation or recompletion of the well.
In other embodiments, the sealing devices can be used as part of a casing string which is run into a cased wellbore. Cement is then pumped downhole to create a plug in the wellbore. Water is then pumped down on top of the cement. Alternatively, water or other fluid may be disposed within the well due to seepage from the formation or through the cement plug. Thereafter, the pump is activated through one or more of the methodologies discussed above to cause the water or other fluid to be pumped into the sealing chamber of the expandable sealing element causing the expandable sealing element to inflate and seat against an inner wall surface of the wellbore. Disposing the sealing device above the cemented plug mitigates gas migration from reaching the surface of the well that might otherwise have migrated through microfractures contained in the cement plug. To further reduce gas migration to the surface, a second cement plug can be installed above the sealing device to provide greater mitigation of gas migration.
Referring now to
Referring to
As illustrated in
With continued reference to
It is to be understood that the invention is not limited to the exact details of construction, operation, exact materials, or embodiments shown and described, as modifications and equivalents will be apparent to one skilled in the art. For example, the housing containing the pump and, if included, the motor, microcontroller, etc. can be included within its own separate sub assembly that is releasably secured within the work or tool string. Alternatively, these components can be included in a collar releasably or permanently secured to the mandrel. Moreover, the pump is not required to cause inflation of the expandable sealing element. Instead, a burst disk and check valve along with hydrostatic pressure can be used to inflate the expandable sealing element and the pump can be used to deflate the expandable sealing element. In addition, the sealing device is not required to be a packer, or a packer as described with respect to