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Title:
A DEVICE FOR TREATING A BOTTOM-HOLE FORMATION WELLBORE
Document Type and Number:
WIPO Patent Application WO/2019/153093
Kind Code:
A1
Abstract:
A device for treating a bottom-hole formation of a wellbore comprises a firing head and seal block assembly at a proximal end thereof and a bullnose assembly at a distal end thereof. A carrier tube extends between the firing head and the bullnose assembly. The carrier tube contains a combustible chemical composition which generates hydrochloric acid gas or hydrofluoric acid gas or a combination thereof when combusted. There is a charge wire electrically connecting the firing head and sealing block assembly to the combustible chemical composition.

Inventors:
BRENNAN, Jordan (2 Bearspaw Road NW, Calgary, Alberta T3L 2P5, T3L 2P5, CA)
BRENNAN, Edward (2 Bearspaw Road NW, Calgary, Alberta T3L 2P5, T3L 2P5, CA)
Application Number:
CA2019/050171
Publication Date:
August 15, 2019
Filing Date:
February 08, 2019
Export Citation:
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Assignee:
LAMROCK CANADA INCORPORATED (2 Bearspaw Road NW, Calgary, Alberta T3L 2P5, T3L 2P5, CA)
International Classes:
E21B43/25; E21B43/22; E21B43/26
Attorney, Agent or Firm:
CAMERON IP (1 Alberni Street, Vancouver, British Columbia V6E 3Z3, V6E 3Z3, CA)
Download PDF:
Claims:
What is claimed is:

1. A device for treating a bottom-hole formation of a wellbore, the device comprising: a firing head and seal block assembly at a proximal end thereof; a bullnose assembly at a distal end thereof; a carrier tube extending between the firing head and seal block assembly and the bullnose assembly, the carrier tube containing a combustible chemical composition which generates hydrochloric acid gas or hydrofluoric acid gas or a combination thereof when combusted; and a charge wire electrically connecting the firing head and sealing block assembly to the combustible chemical composition.

2. The device as claimed in claim 1 wherein the carrier tube has a plurality of lateral openings.

3. The device as claimed in claim 1 further including a spacer tube extending between the firing head and seal block assembly and the carrier tube.

4. The device as claimed in claim 3 further including a mandrel coupling the spacer tube to the carrier tube.

5. A device for treating a bottom -hole formation of a wellbore, the device comprising: a firing head and seal block assembly at a proximal end thereof; a bullnose assembly at a distal end thereof; a first assembly coupled to the firing head and seal block assembly, the first assembly including a spacer tube coupled to a carrier tube, the carrier tube containing a combustible chemical composition which generates hydrochloric acid gas or hydrofluoric acid gas or a combination thereof when combusted; a second assembly coupled to the bullnose assembly, the second assembly including a spacer tube coupled to a carrier tube, the carrier tube containing a combustible chemical composition which generates hydrochloric acid gas or hydrofluoric acid gas or a combination thereof when combusted, and the second assembly being coupled to the first assembly; and charge wires electrically connecting the firing head and sealing block assembly to the combustible chemical composition in the first assembly and the combustible chemical composition in the second assembly.

6. The device as claimed in claim 5 wherein the carrier tube of the first assembly and the carrier tube of the second assembly each has a plurality of lateral openings.

7. The device as claimed in claim 5 further including a mandrel coupling the spacer tube of the first assembly to the carrier tube of the first assembly.

8. The device as claimed in claim 5 further including a mandrel coupling the spacer tube of the second assembly to the carrier tube of the second assembly.

9. The device as claimed in claim 5 further including a hang off sub coupling the first assembly to the second assembly.

10. A device for treating a bottom -hole formation of a wellbore, the device comprising: a firing head; a combustible carrier tube containing a combustible chemical composition which generates hydrochloric acid gas or hydrofluoric acid gas or a combination thereof when combusted; and a charge wire electrically connecting the firing head to the combustible carrier tube.

11. The device as claimed in any one of claims 1, 5 or 10 wherein the combustible chemical composition comprises between 30% and 60% by weight hexachloroethane and between 40% and 70% by weight ammonium nitrate.

12. The device as claimed in any one of claims 1, 5 or 10 wherein the combustible chemical composition comprises between 30% and 60% by weight polyvinyl chloride and between 40% and 70% by weight ammonium nitrate.

13. The device as claimed in any one of claims 1, 5 or 10 wherein the combustible chemical composition comprises between 0% and 5% by weight polyvinyl chloride, between 25% and 55% by weight hexachloroethane, and between 40% and 70% by weight ammonium nitrate.

14. The device as claimed in any one of claims 1, 5 or 10 wherein the combustible chemical composition comprises between 5% and 25% by weight polytetrafluoroethylene, between 25% and 55% by weight hexachloroethane, and between 40% and 70% by weight ammonium nitrate.

15. The device as claimed in any one of claimed 11 to 14 wherein the combustible chemical composition further comprises between 2% and 12% by weight potassium dichromate.

16. The device as claimed in any one of claims 1 to 15 wherein the combustible chemical composition is disposed in a sleeve.

17. The device as claimed in any one of claims 1 to 15 wherein the combustible chemical composition is disposed within a polyvinyl chloride sleeve.

18. The device as claimed in claim 17 or 18 wherein the combustible chemical composition includes a plurality of puck shaped members.

19. The device as claims in claim 18 wherein the combustible chemical composition further includes an adhesive binding adjacent ones of the solid puck shaped members.

20. The device as claimed in claim 18 or 19 wherein the combustible chemical composition further includes a combustion catalyst.

Description:
A DEVICE FOR TREATING A BOTTOM-HOLE FORMATION WELLBORE

BACKGROUND OF THE INVENTION

Field of the Invention

[0001] The present invention relates to a device for treating a wellbore and, in particular, to a device which generates hydrochloric acid gas, hydrofluoric acid gas or a combination thereof to treat a bottom-hole of a wellbore.

Description of the Related Art

[0002] It is known that a decrease in the permeability of a bottom-hole formation of a wellbore may result in a decrease in hydrocarbon recovery. The decrease in the permeability of the bottom-hole formation may be the result of dilatation due to asphaltic deposits or volumetric readjustments of bore space structure. Alternatively, the decrease in the permeability of the bottom-hole formation may be the result of clogging from clay swelling or deposits of foreign matter such as mechanical impurities, filtrates, well knitting, drill-in fluids, well development fluids, and cement. Sand and paraffin-hydrate plugs are also known to cause a decrease in the permeability of the bottom-hole formation as are calcium carbonate scale, calcium sulfate scale, and other scale. It is therefore desirable to treat the bottom-hole formation of a wellbore to increase the permeability of a bottom-hole formation and increase hydrocarbon recovery.

SUMMARY OF THE INVENTION

[0003] It is an obj ect of the present invention to provide an improved device for treating a bottom-hole formation of a wellbore. [0004] There is accordingly provided a device for treating a wellbore. The device comprises a firing head and seal block assembly at a proximal end thereof and a bullnose assembly at a distal end thereof. A carrier tube extends between the firing head and seal block assembly and the bullnose assembly. The carrier tube contains a combustible chemical composition which generates hydrochloric acid gas or hydrofluoric acid gas or a combination thereof when combusted. There is a charge wire electrically connecting the firing head and sealing block assembly to the combustible chemical composition. The carrier tube may have a plurality of lateral openings. There may be a spacer tube extending between the firing head and seal block assembly and the carrier tube. A mandrel may couple the spacer tube to the carrier tube. There may be a perforating gun coupled to the carrier tube.

[0005] There is also provided a device for treating a bottom-hole formation of a wellbore. The device comprises a firing head and seal block assembly at a proximal end thereof and a bullnose assembly at a distal end thereof. A first assembly is coupled to the firing head and seal block assembly. The first assembly includes a spacer tube coupled to a carrier tube. The carrier tube contains a combustible chemical composition which generates hydrochloric acid gas or hydrofluoric acid gas or a combination thereof when combusted. A second assembly is coupled to the bullnose assembly. The second assembly includes a spacer tube coupled to a carrier tube, the carrier tube containing a combustible chemical composition which generates hydrochloric acid gas or hydrofluoric acid gas or a combination thereof when combusted. The first assembly is coupled to the second assembly. Charge wires electrically couple the firing head and sealing block assembly to the combustible chemical composition in the first assembly and to the combustible chemical composition in the second assembly. The carrier tube of the first assembly and the carrier tube of the second assembly may each have a plurality of lateral openings. A mandrel may couple the spacer tube of the first assembly to the carrier tube of the first assembly. A mandrel may couple the spacer tube of the second assembly to the carrier tube of the second assembly. A hang off sub may couple the first assembly to the second assembly. [0006] There is further provided a device for treating a bottom-hole formation of a wellbore. The device comprises a firing head and a combustible carrier tube containing a combustible chemical composition which generates hydrochloric acid gas or hydrofluoric acid gas or a combination thereof when combusted. A charge wire electrically couples the firing head to the combustible carrier tube.

[0007] The combustible chemical composition may comprise between 30% and 60% by weight hexachloroethane and between 40% and 70% by weight ammonium nitrate. The combustible chemical composition may alternatively comprise between 30% and 60% by weight polyvinyl chloride and between 40% and 70% by weight ammonium nitrate. The combustible chemical composition may still alternatively comprise between 0% and 5% by weight polyvinyl chloride, between 25% and 55% by weight hexachloroethane, and between 40% and 70% by weight ammonium nitrate. The combustible chemical composition may still yet alternatively comprise between 5% and 25% by weight polytetrafluoroethylene, between 25% and 55% by weight hexachloroethane, and between 40% and 70% by weight ammonium nitrate.

[0008] The combustible chemical composition may be disposed in a sleeve. The sleeve may be a polyvinyl chloride sleeve. The combustible chemical composition may include a plurality of solid puck shaped members. The combustible chemical composition may further include an adhesive binding adjacent ones of the solid puck shaped members. The combustible chemical composition may further include a combustion catalyst.

BRIEF DESCRIPTIONS OF DRAWINGS

[0009] The invention will be more readily understood from the following description of the embodiments thereof given, by way of example only, with reference to the accompanying drawings, in which:

[0010] Figure 1 is an elevation, partially sectional, view showing a device for treating a bottom-hole formation of a vertical wellbore; [0011] Figure 2 is an exploded, perspective view of the device for treating a bottom- hole formation of a wellbore shown in Figure 1;

[0012] Figure 3 is an elevation, fragmentary and partially sectional, view of the device for treating a bottom -hole formation of a wellbore shown in Figure 1; [0013] Figure 4 is a perspective view of a first carrier tube of the device for treating a bottom-hole formation of a wellbore shown in Figure 1;

[0014] Figure 5 is a perspective view of a second carrier tube of the device for treating a bottom-hole formation of a wellbore shown in Figure 1;

[0015] Figure 6 is a schematic, exploded view showing a connection between a sleeve of a combustible chemical composition of the first carrier tube and a sleeve of a combustible chemical composition of the second carrier tube of the device for treating a bottom-hole formation of a wellbore of Figure 1;

[0016] Figure 7 is an elevation view of the sleeve of the combustible chemical composition of the first carrier tube of the device for treating a bottom-hole formation of a wellbore shown in Figure 1; and

[0017] Figure 8 is an elevation view of the sleeve of the combustible chemical composition of the second carrier tube of the device for treating a bottom-hole formation of a wellbore shown in Figure 1.

DESCRIPTIONS OF THE PREFERRED EMBODIMENTS [0018] Referring to the drawings and first to Figure 1, there is shown a device 10 for treating a bottom-hole formation 12 of a wellbore 14. The device 10 is lowered into the wellbore 14 by a wireline 16 in this example. However, in other examples, coiled tubing or other suitable means may be employed to lower the device 10 into the wellbore 14. The wellbore 14 is cased with a perforated casing 18. Gas generated by the device 10 to treat the bottom -hole formation 12 of the wellbore 14 flows through perforations in the perforated casing 18, for example perforations 20a and 20b of the perforated casing 18, into corresponding perforations in the bottom -hole formation 12, for example perforations 22a and 22b of the bottom-hole formation 12, as indicated generally by arrows 24a and 24b. It will be understood by a person skilled in the art that the device 10 may also be employed to treat a wellbore provided with a slotted liner or an open hole wellbore. It will also be understood by a person skilled in the art that the device 10 may be deployed in a vertical wellbore or horizontal wellbore. It will also be understood by a person skilled in the art that the device may be deployed in a producing wellbore or an injection wellbore.

[0019] The device 10 is shown in greater detail in Figure 2. The device 10 comprises a firing head and sealing block assembly 30 at a proximal end thereof and a bullnose assembly 32 at a distal end thereof. A proximal end of a first spacer tube 34 is coupled to the firing head and sealing block assembly 30. A first carrier tube 36 is coupled to a distal end of the first spacer tube 34. A second spacer tube 38 is coupled to a distal end of the first carrier tube 36. A second carrier tube 40 is coupled to a distal end of the second spacer tube 38. A distal end of the second carrier tube 40 is coupled to the bullnose assembly 32. The first spacer tube 34 and the first carrier tube 36 are coupled by a mandrel 42 and together form a first assembly 44 of the device 10 for treating the bottom-hole formation of the wellbore. The second spacer tube 38 and the second carrier tube 40 are also coupled by a mandrel 46 and together form a second assembly 48 of the device 10 for treating the bottom-hole formation of the wellbore. A hang off sub 50 couples the first assembly 44 of the device 10 for treating the bottom -hole formation of the wellbore to the second assembly 48 of the device 10 for treating the bottom -hole formation of the wellbore.

[0020] The first carrier tube 36 and the second carrier tube 40 each contain a combustible chemical composition which generates hydrochloric acid gas or hydrofluoric acid gas or a combination thereof when combusted. Figure 3 shows a combustible chemical composition 52 contained in the first carrier tube 36 and a combustible chemical composition 54 contained in the second carrier tube 40. In this example, the combustible chemical composition 52 is contained in the first carrier tube 36 and comprises a plurality of puck shaped members, for example puck shaped member 52a and 52b, which are fitted into a sleeve 53. The sleeve 53 may be formed of polyvinyl chloride and there may be epoxy lining an inner surface of the sleeve 53. In this example, the combustible chemical composition 54 is contained in the second carrier tube 40 and comprises a plurality of puck shaped members, for example puck shaped member 54a and 54b, which are fitted into a sleeve 55. The sleeve 55 may be formed of polyvinyl chloride and there may be epoxy lining an inner surface of the sleeve 55. The combustible chemical compositions 52 and 54 will combust through the respective sleeves 53 and 55.

[0021] A charge wire 56 provides a charge to combust the combustible chemical composition 52 contained in the first carrier tube 36. A flow through charge wire 58 provides a charge to combust the combustible chemical composition 54 contained in the second carrier tube 40. In this example, at least one of the puck shaped members is a combustion catalyst comprising epoxy resin, potassium dichromate, and ammonium nitrate. However, it will be understood by a person skilled in the art that a combustion catalyst is not required but any suitable combustion catalyst may be employed. The first carrier tube 36 and the second carrier tube 40 are each respectively shown in Figures 4 and 5. The first carrier tube 36 has a plurality of lateral openings, for example, slots 62a and 62b. The second carrier tube 40 has a plurality of lateral openings, for example, slots 64a and 64b. The hydrochloric acid gas or hydrofluoric acid gas or a combination thereof, generated when the combustible chemical composition 52 contained in the first carrier tube 36 and the combustible chemical composition 54 contained in the second carrier tube 40 are combusted, flows through the slots 62a and 62b in the first carrier tube 36 and the slots 64a and 64b in the second carrier tube 40.

[0022] The combustible chemical compositions contained in the first carrier tube 36 and the second carrier tube 40 may be the same or may be different. Examples of the combustible chemical compositions are set out below. Examples 1-3 and 5-7 generate hydrochloric acid gas and examples 4 and 8 generate hydrochloric acid gas and hydrofluoric acid gas.

Example 1

Component _ Percent by Weight

Hexachloroethane 30% to 60%

Ammonium nitrate 40% to 70%

Example 2

Component _ Percent by Weight

Chlorinated polyvinyl 30% to 60%

chloride

Ammonium nitrate 40% to 70%

Example 3

Component _ Percent by Weight

Chlorinated polyvinyl 0% to 5%

chloride

Hexachloroethane 25% to 55%

Ammonium nitrate 40% to 70%

Example 4

Component _ Percent by Weight

Polytetrafluoroethylene 5% to 25%

Hexachloroethane 25% to 55%

Ammonium nitrate 40% to 70% Example 5

Component Percent by Weight

Hexachloroethane 30% to 60% Ammonium nitrate 40% to 70% Potassium Dichromate 2% and 12%.

Example 6

Component Percent by Weight

Chlorinated polyvinyl 30% to 60% chloride

Ammonium nitrate 40% to 70%

Potassium Dichromate 2% and 12%.

Example 7

Component Percent by Weight

Chlorinated polyvinyl 0% to 5% chloride

Hexachloroethane 25% to 55% Ammonium nitrate 40% to 70% Potassium Dichromate 2% and 12%.

Example 8

Component _ Percent by Weight

Polytetrafluoroethylene 5% to 25%

Hexachloroethane 25% to 55%

Ammonium nitrate 40% to 70%

Potassium Dichromate 2% and 12%.

[0023] In the above examples, a chlorinated polyvinyl chloride is employed. However, in other examples, any suitable polyvinyl chloride may be employed. [0024] A self-levelling, chemical resistant, high performance sealant may be employed to seal each end of the device 10. In this example, the sealant is a two-part polysulfide sealant offered under the trademark Thiokol®. However, it will be understood by a person skilled in the art that silicone based sealants or other suitable sealants may be employed as an alternative to the Thiokol® sealant. It will also be understood by a person skilled in the art that the device may be sealed mechanically or by other suitable means.

[0025] An adhesive may be employed to bind the puck shaped members. The adhesive may be a cured epoxy resin system which is a mixture of an epoxy resin, a hardener and a plasticizer. The epoxy resin employed may include a typical bispenol A type resin. An example of an adhesive is set out below. However, it will be understood by a person skilled in the art that other suitable adhesives or binding agents may be employed.

Component _ Percent by Weight

Epoxy resin (DER-331®) about 80%

Plasticizer about 10%

Hardener (Aradur 42BD ®) about 10% [0026] Referring now to Figure 6, there is shown a connection between the sleeve 53 of the combustible chemical composition of the first carrier tube 36 (not shown in Figure 6) and the sleeve 55 of the combustible chemical composition the second carrier tube 40 (not shown in Figure 6). A firing head 66 is tethered to the wireline 16. The firing head 66 is electrically connected to the sleeve 53 of the combustible chemical composition of the first carrier tube 36 by the charge wire 56. The firing head 66 is also electrically connected to the sleeve 55 of the combustible chemical composition of the second carrier tube 40 by the flow through charge wire 58. There is a first switch 72 connected in series between the firing head 66 and the sleeve 53 of the combustible chemical composition of the first carrier tube 36. There is a second switch 74 connected in series between the firing head 66 and the sleeve 55 of the combustible chemical composition of the second carrier tube 40. The first switch 72 and the second switch 74 allow for selective combustion of the combustible chemical composition of the first carrier tube 36 and the combustible chemical composition of the second carrier tube 40. [0027] The sleeve 53 of the combustible chemical composition of the first carrier tube

36 and the sleeve 55 of the combustible chemical composition of the second carrier tube 40 are each respectively shown in greater detail in Figures 7 and 8. The sleeve 53 of the combustible chemical composition of the first carrier tube 36 (not shown in Figure 7) generally comprises a tube portion 76 which contains the combustible material and a sealing cap 78. The tube portion 76 is combustible and may combust, or partially combust, with the combustible chemical composition to generate hydrochloric acid gas or hydrofluoric acid gas or a combination thereof. The sleeve 55 of the combustible chemical composition of the second carrier tube 40 (not shown in Figure 6) generally comprises a tube portion 80 which contains the combustible material and a sealing cap 82. The tube portion 80 is combustible and may combust, or partially combust, with the combustible chemical composition to generate hydrochloric acid gas or hydrofluoric acid gas or a combination thereof.

[0028] It will be understood by a person skilled in the art that although the device 10 disclosed herein comprises a first carrier tube 36 and a second carrier tube 40, in other examples, the device may comprise a single carrier tube or any number of suitable carrier tubes.

[0029] It will also be understood by a person skilled in the art that many of the details provided above are by way of example only, and are not intended to limit the scope of the invention which is to be determined with reference to the following claims.