This specification relates to wellbore packers, for example, monitoring sealing efficiencies of wellbore packers.
When working on a wellbore, the wellbore sometimes needs to be sealed for extended periods of time. The seal often needs to be maintained for an extended period of time to prevent injury to workers or an environmental release. In such a situation, packers can be deployed to seal the wellbore. A packer can seal the wellbore with an elastomer seal that extends radially outward from a cylindrical core to seal against the wall of a wellbore.
This specification describes technologies relating to sealing a wellbore. This specification also describes technologies for monitoring sealing efficiencies of wellbore packers.
Certain aspects of the subject matter described here can be implemented as a wellbore monitoring system. The system includes a packing element configured to at least partially seal an uphole portion of a wellbore from a downhole portion of the wellbore. A first annular pressure sensor is positioned uphole of the packing element. The first annular pressure sensor is configured to measure a first pressure within the wellbore uphole of the packing element. A second annular pressure sensor is positioned downhole of the packing element. The second annular pressure sensor is configured to measure a second pressure within the wellbore downhole of the packing element. A control sub-assembly is configured to be positioned within the wellbore. The control sub-assembly is configured to monitor a sealing efficiency of the system by comparing the first pressure and the second pressure.
With or without any of the other aspects, the system can include a cylindrical body that supports the packing element, the first annular pressure sensor, the second annular pressure sensor and the control sub-assembly. A first packer slip can be positioned nearer an uphole end of the cylindrical body than a downhole end of the cylindrical body. The first packer slip can at least partially support the system. A second packer slip can be positioned nearer the downhole end of the cylindrical body than the uphole end of the cylindrical body. The second packer slip can at least partially support the system.
With or without any of the other aspects, the packing element can be positioned between the first packer slip and the second packer slip. With or without any of the other aspects, the control-subassembly can include one or more processors and a computer-readable medium storing instructions executable by the one or more processors to perform operations. The operations can include receiving, from a surface of the wellbore, instructions to perform sealing operations within the wellbore, and transmitting to the control sub-assembly at least a portion of the sealing instructions. The packing element can at least partially seal the wellbore in response to the sealing instructions.
With or without any of the other aspects, the operations can include receiving, from at least one of annular pressure sensors, status signals representing a sealing status of the packing element, and transmitting, to the surface of the wellbore, the status signals.
With or without any of the other aspects, the status signals can include a state of the system, which can include either an engaged or a disengaged state. An engaged state can include the first slip being in an extended position, the second slip being in an extended position, or the packing element being in an extended position extending from the cylindrical body to a wall of the wellbore. A disengaged state can include the first packing slip, the second packing slip, the packing element to not extend from the cylindrical body to the wall of the wellbore.
With or without any of the other aspects, the system can include one or more transmitters at the surface of the wellbore that can transmit the sealing instructions to the one or more processors. The system can include one or more receivers at the surface of the wellbore that can receive the status signals from the one or more processors.
With or without any of the other aspects, the one or more transmitters and the one or more receivers can be configured to communicate wireless with the one or more processors.
With or without any of the other aspects, the system can include one or more repeaters that can be positioned between the surface and the control sub-assembly within the wellbore, and that can boost a strength of a wireless signal between the one or more transmitters or the one or more receivers and the one or more processors.
With or without any of the other aspects, the control-subassembly can include a power source that can be positioned within the wellbore, that can be operatively coupled to the one or more processors and that can provide operating power to the one or more processors.
With or without any of the other aspects, the system can include a hydraulic power unit that can be operatively coupled to the one or more processors, and that can receive at least the portion of the instructions from the one or more processors.
With or without any of the other aspects, the hydraulic power unit can include a hydraulic pump fluidically connected to the system, and that can supply hydraulic fluid at a pressure sufficient to activate the system.
Certain aspects of the subject matter described here can be implemented as a method of sealing a wellbore. A control sub-assembly deployed within a wellbore receives sealing instructions to perform sealing operations within the wellbore from a surface of the wellbore. The control assembly transmits at least a portion of the sealing instructions to a packer sub-assembly that includes a cylindrical body, a first packer slip positioned nearer an uphole end of the cylindrical body than a downhole end of the cylindrical body, a second packer slip positioned nearer the downhole end of the cylindrical body than the uphole end of the cylindrical body, a packing element positioned between the first packer slip and the second packer slip, a first annular pressure sensor positioned uphole of the packing element, and a second annular pressure sensor positioned downhole of the packing element. Each of the first uphole packer slip and the second packer slip can at least partially support the packer sub-assembly. The packing elements can at least partially seal the wellbore. The first annular pressure sensor and the second annular pressure sensor can measure a first pressure and a second pressure, respectively, within the wellbore uphole of and downhole of, respectively, of the packing element. The packer sub-assembly is activated to at least partially seal the wellbore. An effectiveness of the seal is determined by comparing the first pressure and the second pressure.
With or without any of the other aspects, the packer sub-assembly can transmit status signals representing a status of the packer sub-assembly to the control assembly. The control assembly can receive status signals from the packer sub-assembly.
With or without any of the other aspects, the control assembly can transmit the status signals from the packer sub-assembly to the surface of the wellbore.
With or without any of the other aspects, the packer sub-assembly can include a hydraulic unit that includes a hydraulic pump. To activate the first packer slip, the second packer slip, and the packing element to at least partially seal the wellbore, the hydraulic pump can pump hydraulic fluid to mechanically activate the first packer slip, the second packer slip or the packing element.
Certain aspects of the subject matter described here can be implemented as a method. To form a bottom hole assembly that can be deployed in a wellbore to seal the wellbore, a control assembly and a packer sub-assembly can be assembled. The control assembly includes one or more processors and a computer-readable medium storing instructions executable by the one or more processors to seal the wellbore. The packer sub-assembly can seal the wellbore. The bottom hole assembly is deployed in the wellbore. From a surface of the wellbore, the control subassembly controls the packer sub-assembly using wireless signals to seal the wellbore.
With or without any of the other aspects, the control assembly can receive status signals representing a status of sealing operations from the packer sub-assembly. The control assembly can wirelessly transmit the status signals to the surface of the wellbore.
With or without any of the other aspects, the status signals can include a state of the packer sub-assembly. The state can include either an on state or an off state, and a hydraulic pressure of the packer sub-assembly.
With or without any of the other aspects, the status signals can include a pressure differential across the packer sub-assembly.
The details of one or more implementations of the subject matter described in this specification are set forth in the accompanying drawings and the description below. Other features, aspects, and advantages of the subject matter will become apparent from the description, the drawings, and the claims.
Like reference numbers and designations in the various drawings indicate like elements.
Production and injection wellbores often need to be sealed for maintenance or repair operations. Such repairs and maintenance can include replacing damaged casing, replacing damaged tubing, inspecting well components, or any other necessary operation. During such operations, the wellbore can be sealed to allow safe access to the section of the wellbore requiring attention. The seal can help prevent environmental releases, fires, explosions, asphyxiation, and any other potential hazard resulting from a hydrocarbon release.
Certain operations can require a seal to be in place and secured for an extended period of time. During that time, the seal integrity should be monitored to ensure that there is no hydrocarbon release. Monitoring the seal integrity can be difficult, and the likelihood of a seal failure increases with the amount of time the seal is in place.
A packer can be used to provide the necessary seal during repair and maintenance operations, but a standard packer can be difficult to set and can often take multiple attempts to provide a proper seal. Testing the seal between each attempt can be cumbersome and time consuming. Often times a packer is “dumb”. That is, the packer is incapable of monitoring its own sealing integrity. As such, auxiliary equipment is often needed to monitor the sealing integrity of a packer.
This specification discusses a smart packer that can be included in a completion or testing string that is meant to alleviate such issues. The smart packer includes a battery pack to power the unit, a control unit to control the packer, a rubber packing element to seal a drilling annulus, upper and lower pressure sensors to ensure the integrity/seal of the rubber element, and upper and lower set of slips to anchor the packer to the walls of a wellbore. The smart packer communicates wirelessly with the surface and is able to transmit data in real time. The smart packer is capable of actuating (for example, engaging and disengaging) it slips and rubber elements multiple times before needing to be retrieved. The smart packer eliminates risks such as, prematurely setting or releasing due to differential pressures while circulating, losses or uncontrolled manipulation of the pipe. The setting mechanism ensures the proper setting force is delivered to the packing element (also known as packing rubber element or packer rubber element) to guarantee the zonal isolation, and eliminate the slick line operations. The smart packer can be used in a vertical, horizontal, or deviated wellbore.
At the surface 116, a transmitter 113 and a receiver 112 can be positioned to communicate with the control sub-assembly 101. The packer installation system 100 can also include one or more repeaters 114 that can be positioned between the surface 116 and the bottom hole assembly 102 within the wellbore 106. The one or more repeaters 114 can boost a strength of a wireless signal between the control sub-assembly 101 and the surface 116.
A first annular pressure sensor 206 is positioned uphole of the packing element 214 and measures a pressure within the wellbore 106 uphole of the packing element 214. A second annular pressure sensor 218 is positioned downhole of the packing element 214 and measures a pressure in the wellbore downhole of the packing element 214. Each pressure sensor can be fixedly attached to the cylindrical body 220 of the packer sub-assembly 103. While the illustrated implementation shows a single packing element and two pressure sensors, additional packing elements and sensors may be used. For example, if monitor seal is required, an additional packing element and sensor could be added. The additional sensor can monitor a pressure between the two packing elements while the packer sub assembly is in place.
The control sub-assembly 101 is positioned at one end of the packer sub-assembly 103 and can include a power source 210 and one or more processors 204.
The control sub-assembly also includes a power source 210 that can be positioned within the wellbore. The power source 210 can be operatively coupled to the one or more processors 204 and can provide operating power to the one or more processors 204. In some implementations, the power source can be a stand-alone power source positioned within the wellbore 106, such as a lithium ion battery (or other rechargeable power source). The packer installation system 100 can include one or more hydraulic power units, such as a first hydraulic power unit 310, a second hydraulic power unit 312, or a third hydraulic power unit 314, operatively coupled to the one or more processors 204. Any of the hydraulic power units can receive at least a portion of a set of sealing instructions from the one or more processors 204. The hydraulic power units may receive instructions to change states (“on” command or “off” command) of the hydraulic pump, set a target pressure for the hydraulic pump, or any other command that can be executed by the hydraulic power unit. In some implementations, the different hydraulic power units may be interconnected to allow fluidic communication between each hydraulic power unit. The interconnection can allow a hydraulic power unit to control multiple sealing sub-assemblies in the event of a hydraulic power unit failure. In some implementations, each hydraulic power unit can include its own one or more sensors, for example, a pressure sensor or other sensor. Each hydraulic power unit can receive measurements (or other information) sensed by its one or more sensors, and transmit the same to the control sub-assembly 101.
Once the hydraulic power unit 401 has received a signal to activate the packer sub-assembly 103, the hydraulic pump 404 moves hydraulic fluid from a full hydraulic reservoir 402a to an unexpanded expansion member 406a. The unexpanded expansion member 406a begins to expand and become expanded expansion member 406b. Similarly, the full hydraulic reservoir 402a becomes the depleted hydraulic reservoir 402b during the activation of the packer sub-assembly 103. That is, activating at least one of the packing slips, such as the first packer slip 212, includes pumping hydraulic fluid to mechanically activate the respective packing slip with the hydraulic pump 404. The expanded expansion member 406b moves a wedged-shaped mandrel 408 towards the packer first packer slip 212. The wedge-shaped mandrel 408 causes the packer first packer slip 212 to extend radially outward from the packer sub-assembly 103 and towards the wall of the wellbore 106. Once sealing operations are completed, the control sub-assembly 101 can send a signal to the hydraulic pump 404 to pump hydraulic fluid from the expanded expansion member 406b back into the depleted hydraulic reservoir 402b. The packer sub-assembly 103 can include a retraction device, such as a spring, to return the wedge-shaped mandrel 408 and packer first packer slip 212 back into the retracted position once the hydraulic fluid has been removed from the expanded expansion member 406b. In some implementations, the hydraulic power unit 401 may be fluidically connected to a separate hydraulic power unit in another part of the packer sub-assembly 103. Such a connection allows for a single hydraulic power unit to control multiple components within the packer sub-assembly 103 in the event of a failure of one of the hydraulic power units, such as hydraulic power unit 401.
Once the hydraulic power unit 501 has received a signal to activate the packing element 214, the hydraulic pump 504 moves hydraulic fluid from a full hydraulic reservoir 502a to an unexpanded expansion member 506a. The unexpanded expansion member 506a begins to expand and become expanded expansion member 506b. Similarly, the full hydraulic reservoir 502a becomes the depleted hydraulic reservoir 502b during the activation of the packing element 214. The expanded expansion member 506b moves a wedged-shaped mandrel 508 towards packing element 214. The wedge shaped mandrel 408 causes the packing element 214 to extend radially outward from the packer sub-assembly 103 and towards the wall of the wellbore 106. In some implementations, the mandrel need not be wedge-shaped; instead, the mandrel can be flat and can radially expand the packing elements by compressing them laterally. Once sealing operations are completed, the control sub-assembly 101 can send a signal to the hydraulic pump to pump hydraulic fluid from the expanded expansion member 506b back into the depleted hydraulic fluid reservoir 502b. The packing element 214 can include a retraction device, such as a spring, to return the wedge-shaped mandrel 508 and packing element 214 back into the retracted position once the hydraulic fluid has been removed from the expanded expandable member 506b. In some implementations, the packing element 214 itself may act as the retraction device. In some implementations, the hydraulic power unit 501 may be fluidically connected to a separate hydraulic power unit in another part of the packer sub-assembly 103. Such a connection allows for a single hydraulic power unit to control multiple components within the packer sub-assembly 103 in the event of a failure of one of the hydraulic power units, such as hydraulic power unit 501.
Particular implementations of the subject matter have been described. Other implementations are within the scope of the following claims.
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