Directly initiated addressable power charge

Abstract

A method and apparatus for detonating a power charge in downhole wellbore using a heating element embedded within the energetic material of the power charge.

Claims

1. A tool for use downhole comprising: a firing head; a setting tool; a power charge cartridge assembly disposed within the setting tool, further comprising: a first end, second end, and a longitudinal axis, an energetic material disposed within the power charge cartridge assembly, an igniter disposed in the power charge cartridge assembly adjacent to the energetic material, wherein the igniter comprises an initiation charge and a heating element.

2. The apparatus of claim 1 wherein the igniter is located proximate to the first end of the power charge cartridge assembly.

3. The apparatus of claim 1 wherein the igniter is located proximate to the second end of the power charge cartridge assembly.

4. The apparatus of claim 1 wherein the majority of the volume of the power charge cartridge assembly contains energetic material.

5. The apparatus of claim 1 wherein the setting tool comprises a power charge chamber with a first end and a second end, and a ported sub, wherein the ported sub is coupled to the second end of the power charge cartridge assembly and slideably engaged to the second end of the power charge cartridge assembly.

6. The apparatus of claim 1 wherein the heating element is a resistor.

7. The apparatus of claim 1 further comprising an addressable switch integral with the power charge, where the addressable switch controls the application of electrical energy to the heating element.

8. The apparatus of claim 2 further comprising an electrical hot wire protruding from the first end of the power charge cartridge assembly and electrically coupled to the heating element.

9. The apparatus of claim 2 further comprising an electrical ground wire connecting the heating element to the power charge cartridge assembly.

10. The apparatus of claim 2 further comprising an electrical ground wire protruding from the power charge cartridge assembly and electrically coupled to the heating element.

11. The apparatus of claim 2 further comprising an electrical hot wire connecting the heating element to the power charge cartridge assembly.

12. The apparatus of claim 3 further comprising an electrical hot wire protruding from the first end of the power charge cartridge assembly and electrically coupled to the heating element.

13. The apparatus of claim 3 further comprising an electrical ground wire connecting the heating element to the power charge cartridge assembly.

14. The apparatus of claim 3 further comprising an electrical ground wire protruding from the power charge cartridge assembly and electrically coupled to the heating element.

15. The apparatus of claim 3 further comprising an electrical hot wire connecting the heating element to the power charge cartridge assembly.

16. A power charge cartridge assembly comprising: a first end and a second end; an energetic material disposed within the power charge cartridge assembly; and an igniter disposed in the power charge cartridge assembly adjacent to the energetic material wherein the igniter comprises an initiation charge and a heating element.

17. The apparatus of claim 16 wherein the heating element is a resistor.

18. The apparatus of claim 16 wherein the igniter is proximate to the first end of the power charge cartridge assembly.

19. The apparatus of claim 16 wherein the igniter is proximate to the second end of the power charge cartridge assembly.

20. The apparatus of claim 16 further comprising an addressable switch integral with the power charge, wherein the addressable switch controls the application of electrical energy to the heating element.

21. The apparatus of claim 18 further comprising a hot electrical wire protruding from the first end of the power charge cartridge assembly and electrically coupled to the heating element.

22. The apparatus of claim 18 further comprising an electrical ground wire connecting the heating element to the power charge cartridge assembly.

23. The apparatus of claim 18 further comprising an electrical ground wire protruding from the power charge cartridge assembly and electrically coupled to the heating element.

24. The apparatus of claim 18 further comprising an electrical hot wire connecting the heating element to the power charge cartridge assembly.

25. The apparatus of claim 19 further comprising a hot electrical wire protruding from the first end of the power charge cartridge assembly and electrically coupled to the heating element.

26. The apparatus of claim 19 further comprising an electrical ground wire connecting the heating element to the power charge cartridge assembly.

27. The apparatus of claim 19 further comprising an electrical ground wire protruding from the power charge cartridge assembly and electrically coupled to the heating element.

28. The apparatus of claim 19 further comprising an electrical hot wire connecting the heating element to the power charge cartridge assembly.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) For a thorough understanding of the present invention, reference is made to the following detailed description of the preferred embodiments, taken in conjunction with the accompanying drawings in which reference numbers designate like or similar elements throughout the several figures of the drawing. Briefly:

(2) FIG. 1 shows a side view cutaway of a power charge cartridge assembly.

(3) FIG. 2 shows a side view cutaway of a power charge cartridge assembly

DETAILED DESCRIPTION OF EXAMPLES OF THE INVENTION

(4) In the following description, certain terms have been used for brevity, clarity, and examples. No unnecessary limitations are to be implied therefrom and such terms are used for descriptive purposes only and are intended to be broadly construed. The different apparatus, systems and method steps described herein may be used alone or in combination with other apparatus, systems and method steps. It is to be expected that various equivalents, alternatives, and modifications are possible within the scope of the appended claims.

(5) An example embodiment is shown in FIG. 1 depicting a portion of a tool string 10 that has a firing head 11 and a setting tool 32 connected by threaded connection 20. The firing head 11 receives an electrical signal via contact pin 23 through contact rod 24 and into electrical pin 25. Contact pin 23, contact rod 24, and electrical pin 25 are all electrically insulated from the firing head housing. Electrical pin 25 travels through the adaptor 22 and makes electrical contact with contact pin 18. Contact pin 18 resides in cavity 28 within contact sub 12. Contact pin 18 in this example uses a spring loaded electrical contact to put it in electrical contact with heating element 16. Contact sub 12 is in the first bore 26 of the power charge chamber 14.

(6) The power charge cartridge assembly 31 is located within the power charge chamber 14. The power charge cartridge assembly 31 includes a cylindrical housing 30 that contains the energetic material 13, the initiator charge 17, and a heating element 16 embedded in the initiator charge 17. The combination of the heating element 16 and the initiator charge 17 forms an igniter 33. The heating element 16 may be an electrical resistor. An addressable switch connected to the heating element 16 may be embedded in the power charge cartridge assembly.

(7) The heating element 16 may receive current from the contact pin 18 via the spring loaded electrical contact and then ground out to the outer casing of the power charge chamber 14. The outer housing of the tool string 10 serves as an electrical ground. The hot wire may be directly through the power charge cartridge assembly 31 and into the heating element 16. Then the heating element 16 may ground out to the power charge chamber 14. The current may be supplied via the cylindrical housing 30 to the heating element 16 and then ground out to power charge chamber 14 via a wire. Alternatively, both the hot and the ground wires may be fed through the housing 30 and connect directly to the heating element 16. Alternatively, the hot wire may feed into the cylindrical housing 30, connect to the heating element 16, and then the heating element 16 may ground to the cylindrical housing 30. The distal end 21 of the power charge chamber 14 is coupled to a ported sub 15. When the heating element 16 is energized, it ignites the initiator charge 17 by heating due to electrical resistance, which in turn ignites the power charge 13, and gases expand through the vent bore 19 on the ported sub 15. Ported sub 15 then transfers the gases into the piston of the setting tool 32.

(8) An example embodiment is shown in FIG. 2 depicting a portion of a tool string 100. In this example, there is a firing head 111 coupled to a setting tool 132 via threaded connection 120. The power charge chamber 114 has a power charge 113. The power charge 113 includes an initiator charge 117 with an embedded heating element 116. An electrical signal can be sent to the heating element 116 via the contact pin 123, through the contact rod 124, then electrical pin 125, and through contact pin 118. The contact pin 118 is in the bore 128 of the contact sub 112. The adaptor 122 is used to locate the contact sub 112 axially between the firing head 111 and the power charge chamber 114.

(9) The power charge cartridge assembly 131 is located within the power charge chamber 114. The power charge cartridge assembly 131 includes a cylindrical housing 130 that contains the energetic material 113, the initiator charge 117, and a heating element 116 embedded in the initiator charge 117. The combination of the heating element 116 and the initiator charge 117 is referred to as the igniter 133. The heating element 116 may be an electrical resistor. An addressable switch connected to the heating element 116 may be embedded in the power charge cartridge assembly.

(10) The heating element 116 may receive current from the contact pin 118 via the spring loaded electrical contact and then ground out to the outer casing of the power charge chamber 114. The outer housing of the tool string 110 serves as an electrical ground. The hot wire may be directly through the power charge cartridge assembly 131 and into the heating element 116. Then the heating element 116 may ground out to the power charge chamber 114. The current may be supplied via the cylindrical housing 130 to the heating element 116 and then ground out to power charge chamber 114. Alternatively, both the hot and the ground wires may be fed through the housing 130 and connect directly to the heating element 116. The distal end 121 of the power charge chamber 114 is coupled to a ported sub 115. When the heating element 116 is energized, it ignites the initiator charge 117 due to heating from electrical resistance, which in turn ignites the power charge 113, and gases expand through the vent bore 119 on the ported sub 115. Ported sub 115 then transfers the gases into the piston of the setting tool 132.

(11) In the configuration shown in the example embodiment of FIG. 2 the heating element 116 can ignite the initiator charge 117, which then ignites the power charge 113 from the setting tool side of the power charge cartridge assembly 131 rather than the firing head side as shown in the previous embodiment. As gases are generated by the ignited power charge 113, the gases more efficiently vent into the ported sub 115 via vent bore 119 because they do not have to travel as far through the housing 132. By igniting the power charge 113 from the bottom instead of the top, the gases can immediately start expanding and performing work instead of first building up pressure within the power charge chamber 114. This puts less stress on the tools and allows for greater reusability.

(12) One advantage of the disclosed embodiments is that there is no longer a separate igniter to initiate the power charge. In another example the heating element may directly initiate the power charge without an igniter charge. This further reduces tool complexity since an igniter holder sub is no longer necessary.

(13) Another advantage to the disclosed examples is that an addressable control fire switch can be connected directly to the power charge. Upon combustion, the addressable control fire switch will then be destroyed. The destroyed switch will be unable to send a signal to the surface, which would indicate that the switch was in fact destroyed and thus confirm that the power charge ignited.

(14) The heating element in the igniter may be an electrical resistor that converts electrical energy into heat.

(15) Although the invention has been described in terms of embodiments which are set forth in detail, it should be understood that this is by illustration only and that the invention is not necessarily limited thereto. For example, terms such as upper and lower or top and bottom can be substituted with uphole and downhole, respectfully. Top and bottom could be left and right. Generally downhole tools initially enter the borehole in a vertical orientation, but since some boreholes end up horizontal, the orientation of the tool may change. In that case downhole, lower, or bottom is generally a component in the tool string that enters the borehole before a component referred to as uphole, upper, or top, relatively speaking. The first housing and second housing may be top housing and bottom housing, respectfully. Terms like wellbore, borehole, well, bore, oil well, and other alternatives may be used synonymously. The alternative embodiments and operating techniques will become apparent to those of ordinary skill in the art in view of the present disclosure. Accordingly, modifications of the invention are contemplated which may be made without departing from the spirit of the claimed invention.