Safety system for autonomous downhole tool

Patent metadata

Field	Value
Publication number	US-10352144-B2
Application number	US-201715848825-A
Country	US
Kind code	B2
Filing date	Dec 20, 2017
Priority date	May 23, 2011
Publication date	Jul 16, 2019
Grant date	Jul 16, 2019

Abstract

A tool assembly for performing a wellbore operation including an actuatable tool, a location device, and on-board controller are together dimensioned and arranged to be deployed in the wellbore as an autonomous unit. The actuatable tool, such as a perforating gun having associated charges, perforates a wellbore along a selected zone of interest. The location device, such as casing collar locator, senses the location of the actuatable tool based on a physical signature provided along the wellbore. The on-board controller or micro-processor is configured to send an activation signal to the actuatable tool when the location device has recognized a selected location of the tool based on the physical signature. The tool assembly further includes a multi-gate safety system. The safety system prevents premature activation of the actuatable tool.

First claim

What is claimed is:

1. An integrated tool for downhole fracture operations, comprising:
a plug body having an elastomeric sealing element;
an actuatable setting tool for setting the plug body within a string of casing in a wellbore, the actuatable setting tool having a detonator for setting the plug within the casing string at a selected depth in response to an electrical actuation signal conveyed to the detonator;
a perforating gun for perforating the string of casing at a selected zone of interest, the perforating gun having detonators with associated charges for perforating the string of casing at the selected zone of interest in response to an electrical signal conveyed to the perforating gun;
a position locator for sensing the location of the integrated tool based upon the detection of objects along the wellbore and generating depth signals in response;
an on-board controller for processing the depth signals and for sending electrical signals to activate the plug and the perforating gun at the selected zone of interest; and
a multi-gate safety system in electrical communication with the on-board controller for preventing premature detonation of the actuatable setting tool and the perforating gun, the multi-gate safety system comprising;
(i) control circuitry having one or more electrical switches that are independently operated by the controller in response to separate conditions before permitting the actuation signal to reach the actuatable tool, and
(ii) a first on-board power supply for the on-board controller,
(iii) a second on-board power supply for actuating at least one of the actuatable tool and the perforating gun; and
(iv) a firing capacitor in communication with the on-board controller, wherein at least one of the electrical switches of the multi-gate safety system controls charging of the firing capacitor by the second on-board power supply, wherein the firing capacitor is insufficiently charged to activate the at least one of the actuatable tool and the perforating gun prior to the multi-gate safety system permitting the controller to initiate charging of the firing capacitor;

wherein the integrated tool is dimensioned and arranged to be deployed within the wellbore as an autonomous unit.

2. The integrated tool of claim 1 , wherein the multi-gate safety system comprises at least one of:
(i) a selectively removable battery pack, wherein the battery pack provides power to the control circuitry when the battery pack is installed into the assembly;
(ii) a mechanical pull-tab, wherein the control circuitry is configured to operate an electrical switch upon removal of a mechanical pull-tab from the tool assembly;
(iii) a pressure-sensitive switch that operates only when a designated hydraulic pressure is exceeded;
(iv) an electrical timer switch that is configured to selectively operate one or more switches at one or more designated times after deployment of the tool assembly in the wellbore;
(v) a velocity sensor configured to operate an electrical switch only upon sensing that the tool assembly is traveling a designated velocity;
(vi) a sensor configured to actuate an electrical switch when the tool assembly is substantially vertical; and
(vii) a sensor configured to actuate an electrical switch when the tool assembly is substantially horizontal
wherein operating an electrical switch means either closing such a switch to permit a flow of electrical current through the switch, or opening such a switch to restrict a flow of electrical current through the switch.

3. The integrated tool of claim 2 , further comprising:
the multi-gate system comprises the electrical timer; and
the one or more switches operated by the electrical timer comprises a shunt switch.

4. The integrated tool of claim 3 , wherein:
during a the first designated period of time, the shunt switch is closed; and
at a second designated time, the shunt switch is open.

5. The integrated tool of claim 2 , wherein:
the multi-gate system comprises the electrical timer;
the one or more switches comprises a detonator switch that resides in an open state during a first designated time;
the electrical timer is configured to send a command signal to the detonator switch to close the detonator switch at a second designated time.

6. The integrated tool of claim 5 , wherein:
the first designated time is about 1 to 5 minutes; and
the second designated time is about 4 to 60 minutes.

7. The integrated tool of claim 5 , wherein during a third designated time, the shunt switch is again open.

8. The integrated tool of claim 2 , wherein:
the multi-gate safety system comprises both the mechanical pull-tab and the timer switch; and
deployment of the tool assembly means that the tool assembly is configured for removal of the mechanical pull-tab.

9. The integrated tool of claim 2 , wherein:
the mechanical pull-tab is releasably connected to a cable;
the cable is tethered to a wellhead component over the wellbore; and
the mechanical pull-tab is configured to release upon movement of the tool assembly into the wellbore.

10. The integrated tool of claim 2 , wherein:
the multi-gate safety system comprises both the mechanical pull-tab and the pressure sensitive switch; and
the mechanical pull-tab is configured to provide a mechanical barrier for the activation of the pressure-sensitive switch.

11. The integrated tool of claim 2 , further comprising:
a fishing neck.

12. The integrated tool of claim 2 , further comprising:
a shunt comprising two leads, wherein the shunt is configured to direct electrical current through the leads in a closed position, and to permit a flow of current toward the actuatable tool in an open position.

13. The integrated tool of claim 12 , wherein:
the multi-gate system comprises the electrical timer; and
the one or more switches operated by the electrical timer comprises (i) a switch for closing a connection between the removable battery pack and the control circuitry, (ii) a switch for operating a connection between a firing capacitor and the two leads, (iii) or a combination of the two.

14. The integrated tool of claim 2 , wherein:
the on-board controller is part of an electronic module comprising onboard memory and built-in logic; and
the electronic module is configured to send a signal that initiates detonation of the perforating gun after the tool assembly has traveled to a pre-programmed location in the wellbore.

15. The integrated tool of claim 14 , wherein the built-in logic provides a digital safety barrier based on a predetermined value for (i) tool depth, (ii) tool speed, (iii) travel time, (iv) downhole markers, or (v) combinations thereof.

16. The integrated tool of claim 2 , wherein the multi-gate safety system comprises:
the electrical timer switch; and
a mechanical relay having a timer, wherein the timer for the mechanical relay is configured to activate after the electrical timer switch is closed, and to switch the mechanical relay after a pre-set period of time has passed in order to re-open the electrical timer switch.

17. The integrated tool of claim 2 , wherein the multi-gate safety system comprises:
the selectively removable battery pack; and
a mechanical relay that connects the battery pack to a discharge bank to draw down electrical power from the battery pack.

18. The integrated tool of claim 2 , wherein:
the position locator is a casing collar locator; and
the objects along the wellbore are collars, with the collars being sensed by the collar locator.

19. T

Assignees

• Entchev Pavlin B
• Angeles Boza Renzo M
• King George R
• Stanton Robert C
• Winemiller Elton
• Tolman Randy C
• Sauermilch Peter W
• Gahr Jason Z
• Exxonmobil Upstream Res Co

Inventors

• Entchev Pavlin B
• Angeles Boza Renzo M
• King George R
• Stanton Robert C
• Winemiller Elton
• Tolman Randy C
• Sauermilch Peter W
• Gahr Jason Z

Classifications

• E21B44/005

  Below-ground automatic control systems · CPC title

• E21B43/263 Primary

  using explosives · CPC title

• E21B33/1204 Primary

  permanent; drillable · CPC title

• E21B43/119

  Details, e.g. for locating perforating place or direction · CPC title

• E21B43/26

  by forming crevices or fractures · CPC title