WO2013170372A1

WO2013170372A1 - Apparatus and method for downhole activation

Info

Publication number: WO2013170372A1
Application number: PCT/CA2013/050075
Authority: WO
Inventors: Robert Joe Coon; Steve Cratus Owens
Original assignee: Packers Plus Energy Services Inc.
Priority date: 2012-05-18
Filing date: 2013-01-31
Publication date: 2013-11-21

Abstract

An apparatus and method for activating a device or equipment located inside a wellbore or a tube string inside a wellbore. According to an embodiment, the apparatus comprises a free running or untethered dart and downhole equipment coupled to the tube string. The dart is configured to transmit an electromagnetic signal comprising a magnetic field signal, and the downhole equipment is configured to detect to the electromagnetic signal when the dart is in proximity. The downhole equipment generates a trigger signal or a trigger output for setting the device in response to reception of the electromagnetic signal.

Description

TITLE: APPARATUS AND METHOD FOR DOWNHOLE ACTIVATION

FIELD OF THE INVENTION

[0001] The present invention relates to wellbore equipment, and more particularly, to an apparatus and method for activating a device or equipment inside a wellbore or a downtube in a wellbore.

BACKGROUND OF THE INVENTION

[0002] In wellbore operations, packers may be used to control migration of fluids outside a liner installed in the wellbore. For example, packers may be installed in the annulus between the liner and the wellbore wall to deter migration of the fluids axially along the annulus.

[0003] Packers may be set by hydraulics. Oftentimes, the hydraulic pressure is introduced through the tubular string on which the packer is installed and is communicated to the packer's hydraulically actuated system by a port through the tubular wall, also called a mandrel, on which the packing elements are installed, The port extends through the tubular wall and provides communication from the tubing string inner diameter and the hydraulic cylinder for the packer. There are seals within the cylinder that contain and direct the hydraulic pressure.

[0004] One of the disadvantages of hydraulically set mechanical packers is the port in the tubular wall. In pressuring applications, for example, when fracing a well and/or pressurizing the liner, the hydraulic cylinders are subjected to the pressures being utilized and in some cases, empty cyclic pressures, which results in cylinders moving and seals moving under pressure situations, which can be in the range of 10,000 psi and at fairly high elevated temperatures. Under such conditions, the ports in the casing string for setting chambers introduce a point of weakness and potential failure. Additionally, in high temperature applications, seals, and the like, can degrade, and a leak path can form through the port in the mandrel and into the annulus, past the problematic seals.

[0005] Accordingly, there remains a need for improvements in the art.

BRIEF SUMMARY OF THE INVENTION

[0006] The present invention is directed to a method and apparatus for activating a downhole device such as a packer in a wellbore.

[0007] According to one aspect, the present invention comprises an apparatus for activating a down-hole device such as a packer located in a wellbore.

[0008] According to another aspect, the present invention comprises a method for activating a down-hole device such as a packer located or positioned in a wellbore.

[0009] According to a first embodiment, the present invention comprises apparatus for activating a downhole device in a downhole tube inside a wellbore, said apparatus comprising: a dart module configured to run inside the downhole; a downhole equipment module coupled to the downhole tube inside said wellbore; said dart module comprising a transmitter module including a transmitter antenna and a transmit signal generator, said transmit signal generated being operatively coupled to said transmitter antenna and configured to generate a transmit output signal for transmission by said transmitter antenna; said downhole equipment module comprising a receiver module including a receiver antenna configured to receive said transmit output signal when said dart module is proximate to said downhole equipment, a decoder and an activation module, said receiver antenna being operatively coupled to said decoder, and said decoder being configured to decode transmit output signal and activate said activation module, said activation module comprising a mechanism configured to activate said downhole device. [00010] According to another embodiment, the present invention comprises a method for activating a downhole device coupled to a tube string positioned inside a wellbore, said method comprising the steps of: running a dart through said tube string in the wellbore, said dart being configured with a transmitter antenna and a transmit signal generator; providing said downhole device with a receiver antenna and a receiver module, said receiver antenna being configured to receive said transmit output signal and said receiver module being configured to decode said transmit output signal; receiving said transmit output signal at said downhole device when said dart comes within proximity; and decoding said transmit output signal and generating a trigger signal to activate said downhole device.

[00011] Other aspects and features of the present invention will become apparent to those ordinarily skilled in the art upon review of the following description of embodiments of the invention in conjunction with the accompanying figures.

BRIEF DESCRIPTION OF THE DRAWINGS

[00012] Reference will now be made to the accompanying drawings which show, by way of example, embodiments according to the present invention, and in which:

[00013] Fig. 1 shows in schematic form an apparatus for activating a down-hole device according to an embodiment of the present invention; and

[00014] Fig. 2 shows a cross-sectional view taken along line A-A of the apparatus for activating a down-hole device of Fig. 1.

[00015] Like reference numerals indicate like or corresponding elements or components in the drawings. DETAILED DESCRIPTION OF THE EMBODIMENTS OF THE INVENTION

[00016] Reference is made to Fig. 1 , which shows an apparatus for activating a down- hole device according to an embodiment of the present invention and indicated generally by reference 100. According to an exemplary implementation, the apparatus 100 comprises a first component, i.e. a free running or untethered dart, indicated generally by reference 1 10, and a second component, i.e. a downhole component or equipment, indicated generally by reference 140. It will be appreciated that while embodiments of the present invention are described in the context of an untethered dart arrangement, there may be applications or configurations, where tethering of the dart may be undertaken.

[00017] According to an exemplary implementation, the downhole component 140 is connected, coupled or affixed using suitable fastening techniques into a tubing string or downtube 101 at its respective ends 141 and 142. The tubing string 101 is positioned in a bore hole or well bore in known manner. In Figs. 1 and 2, the bore hole is indicated generally by reference 102, and according to an embodiment, the bore hole comprises an open hole with a wellbore wall 103 adjacent the tubing string 101 and the downhole equipment 140. According to an exemplary implementation, the downhole equipment 140 is configured as a trigger device or mechanism which is operatively coupled to, or integrated with, a downhole device, e.g. a packer (not shown), as will be described in more detail below. According to other embodiments or exemplary implementations, the downhole device comprises downhole tools, such as, sliding sleeves, frac sleeves, cementing stage tools, and the like. The downhole device, e.g. packer, is coupled to the tubing string 101 and the wellbore wall 103 adjacent the packer is open hole and uncased, i.e. with the formation exposed. According to another embodiment, the downhole equipment 140, i.e. receiver and activation device, is integrated with the downhole device, e.g. a packer, as described in more detail below.

[00018] As shown in Fig. 2, the free running dart 1 10 comprises a housing 1 12, a transmitter module or transmitter electronic circuit module 1 14 and an antenna module 1 16. According to an exemplary implementation, the free running dart 1 10 is untethered and dropped or pumped through the tubing string 101. The housing 1 12 comprises a generally cylindrical shape and is fabricated or formed, in known manner, from a composite, composite-metallic material or other high strength material capable of withstanding pressures and other stressors normally experienced in the wellbore 102. According to another aspect, the material for the housing 1 12 is selected so as not to substantially attenuate the emitted signal.

[00019] Referring to Fig. 2, the electronic circuit module 1 14 comprises a power source 120, a signal generator 122 and an amplifier circuit 124. The power source 120 comprises a low power DC source, for example, a 3V to 5V power source supplied by one or more batteries. The signal generator 122 includes a free running oscillator, which according to an embodiment, comprises a 400 Hz oscillator with a 50% duty cycle. The amplifier module 124 is configured to amplify the output of the signal generator (i.e. the free running oscillator) 122 and drive the antenna 1 16. According to an embodiment, the amplifier module 124 comprises an H-Bridge circuit which amplifies and switches the polarity of an output (e.g. current) signal applied to the antenna module 1 16. The antenna module 116 is operatively coupled to the amplifier 124 and configured to convert the output signal into an electromagnetic signal (i.e. a transmit output signal) that is coupled and decoded by the downhole equipment 140 as described in more detail below. According to an embodiment, the antenna 116 comprises an inner solid steel core 130 and a coil exterior 132, for example, a coil wound around the steel core 130 using known techniques. As shown, the antenna 1 16 is mounted axially in the housing 1 12. The electronic circuit module 1 14 comprises discrete and/or integrated electronic components mounted on a circuit board or other suitable carrier installed inside the dart 110. The specific implementation details will be readily apparent to one skilled in the art.

[00020] Reference is again made to Fig. 2, the downhole equipment 140 comprises a housing or casing 145, and a receiver module including a receiver electronic circuit module 144, and an antenna module 146.

[00021] According to another embodiment, the downhole equipment 140 is integrated or installed with the downhole device, for example, a packer device. For example, the packer device is configured with a compartment or housing component suitably sized or dimensioned to receive the electronic circuit module 144 and the antenna module 146.

[00022] As shown in Fig. 2, the antenna module 146 is configured to couple the electromagnetic signal(s) emitted (i.e. transmit output signal) by the antenna 1 16 on the free running (i.e. untethered) dart 1 10 as the dart 1 10 comes into proximity and generate an output signal which is fed to the receiver electronic circuit module 144. According to an embodiment, the receiver antenna module 146 comprises a coil 160 wound on a core 162. The core 162 comprises a hollow and non-metallic bobbin according to an exemplary implementation. As shown, the antenna 146 is positioned axially in the downhole equipment 140 and surrounds a portion of the tube string 101, or according to another embodiment, a section of the tubular portion of a packer, as described in more detail below. According to another aspect, the downhole equipment 140 (or packer) comprises a section of material indicated generally by reference 170, which does not attenuate the magnetic field and thereby facilitates coupling and reception between the transmitter antenna 116 in the free running dart 110 and the receiver antenna 146 in the downhole equipment 140. Suitable material for the section 170 includes inconel.

[00023] Referring to Fig. 2, the receiver electronic circuit module 144 comprises a decoder/discriminator circuit 150, an activation circuit 152, an activator or actuator 154 and a power source 156. The power source 156 is configured to supply the circuits and may be implemented as a low power DC power source comprising one or more batteries. The decoder/discriminator circuit 150 receives the output signal from the receiver antenna 146 and is configured to decode, and/or recognize, the output signal and generate an activation ovitput signal for the activation circuit 152 if the received signal is intended, i.e. addressed, to the downhole equipment 140. The received signal can have a signature based on frequency, polarity, pulse width, pulse number, number of pulses, etc., and the particular implementation details will be within the understanding of one skilled in art.

[00024] The activation circuit 152 is configured to be responsive to an output from the decoder circuit 150. The output is generated in response to decoding a signal intended for the downhole equipment 140. According to an embodiment, the activation circuit 152 comprises a current source which is responsive to the output signal from the decoder 150. The current source may be implemented using discrete components, e.g. transistors, or integrate components, as will be within the understanding of one skilled in the art. According to an exemplary implementation, the activator 154 comprises a nichrome wire or strip that is coupled to the output of the current source, and in response to activation of the current source, the nichrome wire is heated by the current to a temperature and/or duration sufficient to melt or burn a section of a Kevlar string or the like which retains a trigger mechanism coupled to or integrated with the downhole device, e.g. a packer.

[00025] In operation, according to an exemplary implementation, the downhole equipment 140 is installed on the tube string 101 and the tube string 101 is run in the wellbore 102. Adjacent or in the vicinity of the downhole equipment 140, the downhole device, e.g. packer, is installed and operatively coupled to the downhole equipment 140. The free running dart 1 10 is dropped or pumped through the tube string 101 in the wellbore 102. According to an exemplary implementation, the electronic circuit module 1 14 and the antenna module 1 16 for the dart 1 10 generate and emit a magnetic field with an alternating polarity (e.g. 180 degrees) and frequency of 400 Hz. When the dart 1 10 passes by the downhole equipment 140, the antenna 146 detects and receives the magnetic signal emitted by the dart 1 10 and generates an output signal. The output signal is processed, e.g. decoded, by the electronic circuit module 144 and trigger output is generated and operatively coupled to the packer. According to an embodiment, the trigger output comprises a heating element that is heated by electronic circuit module 144 to a temperature sufficient to melt a fusible element on the packer, to subsequently trigger or actuate the packer. For instance, the heating element comprises a nichrome wire and the fusible element comprises a fusible string that holds a trigger mechanism in place on the packer.

[00026] According to another mode of operation, the dart 1 10, i.e. the electronic circuit module 1 14 is configured to generate a magnetic output signal with a predetermined signature or identification characteristics. The electronic circuit module 144 in the downhole equipment 140 is configured to decode the magnetic output signal and discriminate or recognize magnetic output signals having a characteristic predetermined signature. Upon detection of the specified or programmed signal, the electronic circuit module 144 generates the trigger output, for example, as described above.

[00027] The present invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. Certain adaptations and modifications of the invention will be obvious to those skilled in the art. Therefore, the presently discussed embodiments are considered to be illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

Claims

WHAT IS CLAIMED IS:

1. An apparatus for activating a downhole device in a downhole tube inside a wellbore, said apparatus comprising: a dart module configured to run inside the downhole; a downhole equipment module coupled to the downhole tube inside said wellbore; said dart module comprising a transmitter module including a transmitter antenna and a transmit signal generator, said transmit signal generated being operatively coupled to said transmitter antenna and configured to generate a transmit output signal for transmission by said transmitter antenna, wherein said transmit output signal comprises a magnetic field signal; said downhole equipment module comprising a receiver module including a receiver antenna configured to receive said transmit output signal when said dart module is proximate to said downhole equipment, a decoder and an activation module, said receiver antenna being operatively coupled to said decoder, and said decoder being configured to decode transmit output signal and activate said activation module, said activation module comprising a mechanism configured to activate said downhole device.

2. The apparatus as claimed in claim 1 , wherein said transmit output signal comprises a signature associated with said downhole device, and said decoder is configured to recognize said signature and generate an activation output signal for said activation module.

3. The apparatus as claimed in claim 2, wherein said activation module comprises an activation circuit and said mechanism comprises a heatable element operatively coupled to said activation circuit and a heat sensitive retention member, and said heat sensitive retention member being operatively coupled to a trigger mechanism of said downhole device, said activation circuit includes a current source configured to drive said heatable element to a temperature sufficient to severe said heat sensitive retention member and thereby release said trigger mechanism so that said downhole device is actuated.

4. The apparatus as claimed in claim 3, wherein said heatable element comprises a nichrome strip, and said sensitive retention member comprises a Kevlar string having at least a section proximate said nichrome strip so that heating of said nichrome strip melts and severs said Kevlar string thereby releasing said trigger mechanism.

5. The apparatus as claimed in claim 1 , wherein said transmit antenna comprises a steel core antenna.

6. The apparatus as claimed in claim 5, wherein said transmit signal generator comprises a free running oscillator configured to generate said transmit signal comprising a magnetic field signal with a frequency of approximately 400 Hz and a 50% duty cycle.

7. The apparatus as claimed in claim 6, wherein said transmitter module comprises an amplifier module operatively coupled to said transmit signal generator and configured to amplify said transmit signal for said transmit antenna.

8. The apparatus as claimed in claim 7, wherein said amplifier module comprises an H-Bridge circuit configured to amplify said transmit signal comprising a magnetic field signal and further configured to switch polarity of said magnetic field signal.

9. The apparatus as claimed in claim 1, wherein said magnetic field signal comprises a signature associated with said downhole device, and said decoder being configured to recognize said signature and activate said activation module based on recognition of said signature.

10. The apparatus as claimed in claim 1 , wherein said dart module is configured to run untethered inside the downhole.

1 1. A method for activating a downhole device coupled to a tube string positioned inside a wellbore, said method comprising the steps of: running a dart through said tube string in the wellbore, said dart being configured with a transmitter antenna and a transmit signal generator configured to generate a transmit signal comprising a magnetic field signal; providing said downhole device with a receiver antenna and a receiver module, said receiver antenna being configured to receive said transmit output signal and said receiver module being configured to decode said transmit output signal; receiving said transmit output signal comprising said magnetic field signal at said downhole device when said dart comes within proximity; and decoding said transmit output signal and generating a trigger signal to activate said downhole device.

12. The method as claimed in claim 11, wherein said transmit output signal comprising said a magnetic field signal having an alternating polarity.

13. The method as claimed in claim 12, wherein said magnetic field signal comprises a signature associated with said downhole device, and further including the step of decoding said signature and generating said trigger signal if said signature is associated with said downhole device.

14. The method as claimed in claim 1 1, wherein said dart is run untethered through said tube string.