U.S. patent application number 09/736521 was filed with the patent office on 2002-09-19 for high temperature explosives for downhole well applications.
Invention is credited to Behrmann, Lawrence A., Kneisl, Philip, Parrott, Robert A., Voreck, Wallace E., Yang, Wenbo.
Application Number | 20020129940 09/736521 |
Document ID | / |
Family ID | 24960196 |
Filed Date | 2002-09-19 |
United States Patent
Application |
20020129940 |
Kind Code |
A1 |
Yang, Wenbo ; et
al. |
September 19, 2002 |
High temperature explosives for downhole well applications
Abstract
The present invention provides explosive compositions adapted
for use in downhole well applications requiring high temperature
explosives that may be exposed to elevated temperatures for
extended periods of time.
Inventors: |
Yang, Wenbo; (Sugar Land,
TX) ; Parrott, Robert A.; (Houston, TX) ;
Behrmann, Lawrence A.; (Houston, TX) ; Voreck,
Wallace E.; (Sparta, NJ) ; Kneisl, Philip;
(Pearland, TX) |
Correspondence
Address: |
Schlumberger Technology Corporation
Schlumberger Reservoir Completions
14910 Airline Road
P.O. Box 1590
Rosharon
TX
77583-1590
US
|
Family ID: |
24960196 |
Appl. No.: |
09/736521 |
Filed: |
December 13, 2000 |
Current U.S.
Class: |
166/299 |
Current CPC
Class: |
E21B 34/06 20130101;
C06B 25/04 20130101; C06B 25/00 20130101; E21B 23/04 20130101; E21B
43/263 20130101; E21B 29/02 20130101; E21B 43/116 20130101 |
Class at
Publication: |
166/299 |
International
Class: |
E21B 029/02; E21B
043/263; C06B 025/00 |
Claims
We claim:
1. Explosives for use in downhole well devices, comprising one or
more identified high temperature downhole explosives.
2. The explosives of claim 1, wherein the one or more identified
high temperature downhole explosives comprise NONA.
3. The explosives of claim 1, wherein the one or more identified
high temperature downhole explosives are selected from NONA, PENCO,
TNN, T-Tacot, ONT, and TPT.
4. The explosives of claim 1, wherein the one or more identified
high temperature downhole explosives are selected from PATO, BTX,
TPM, ABH, DODECA, Z-Tacot, KHND, and TPB.
5. The explosives of claim 1, wherein the one or more identified
high temperature downhole explosives are selected from DIPAM, HNAB,
bis-HNAB, HNBP, DPBT, DPPM, HNDS, and PADP-I.
6. The explosives of claim 1, wherein the one or more identified
high temperature downhole explosives are selected from NaTNC,
HNBIB, TNC, DAT, DADNPO, ONM, ADNBF, DPO, and PIPA.
7. The explosives of claim 1, further comprising one or more other
explosive compounds.
8. The explosives of claim 7, wherein the one or more other
explosive compounds are selected from HNS, PYX, and HMX.
9. The explosives of claim 1, further comprising one or more of an
energetic material and a fuel.
10. The explosives of claim 1, further comprising one or more of an
energetic material and an oxidizer.
11. The explosives of claim 1, wherein the downhole well devices
are selected from perforating guns, perforating devices, tubing or
casing cutters, tubing release mechanisms, fracing mechanisms,
setting apparatus, explosively opening production valves, and
downhole tool actuators.
12. The explosives of claim 1, wherein the downhole well devices
are part of a tool string.
13. The explosives of claim 1, wherein the downhole well devices
are shaped charges.
14. The explosives of claim 1, wherein the one or more high
temperature downhole explosives are used in the downhole well
devices for explosive components selected from shaped charges,
detonators, detonating cords, boosters, and primers.
15. A downhole device having an explosive component, comprising:
one or more identified high temperature downhole explosives.
16. The downhole device of claim 15, wherein the one or more
identified high temperature downhole explosives comprise NONA.
17. The downhole device of claim 15, wherein the one or more
identified high temperature downhole explosives are selected from
NONA, PENCO, TNN, T-Tacot, ONT, and TPT.
18. The downhole device of claim 15, wherein the one or more
identified high temperature downhole explosives are selected from
PATO, BTX, TPM, ABH, DODECA, Z-Tacot, KHND, and TPB.
19. The downhole device of claim 15, wherein the one or more
identified high temperature downhole explosives are selected from
DIPAM, HNAB, bis-HNAB, HNBP, DPBT, DPPM, HNDS, and PADP-I.
20. The downhole device of claim 15, wherein the one or more
identified high temperature downhole explosives are selected from
NaTNC, HNBIB, TNC, DAT, DADNPO, ONM, ADNBF, DPO, and PIPA.
21. The downhole device of claim 15, wherein the explosive
component further comprises one or more other explosive
compounds.
22. The downhole device of claim 21, wherein the one or more other
explosive compounds are selected from HNS, PYX, and HMx.
23. The downhole device of claim 15, wherein the explosive
component further comprises one or more of an energetic material
and a fuel.
24. The downhole device of claim 15, wherein the explosive
component further comprises one or more of an energetic material
and an oxidizer.
25. The downhole device of claim 15, wherein the device is selected
from perforating guns, perforating devices, tubing or casing
cutters, tubing release mechanisms, fracing mechanisms, setting
apparatus, explosively opening production valves, and downhole tool
actuators.
26. The downhole device of claim 15, wherein the device is part of
a tool string.
27. The downhole device of claim 15, wherein the explosive
component is selected from shaped charges, detonators, detonating
cords, boosters, and primers.
28. A shaped charge made by a process, comprising: (a) inserting a
main body of explosive into a case, the main body of explosive
comprising one or more identified high temperature downhole
explosives; and (b) inserting a liner over the main body of
explosive.
29. The shaped charge made by the process of claim 28, wherein the
one or more defined high temperature downhole explosives comprise
NONA.
30. The shaped charge made by the process of claim 28, wherein the
one or more identified high temperature downhole explosives are
selected from NONA, PENCO, TNN, T-Tacot, ONT, and TPT.
31. The shaped charge made by the process of claim 28, wherein the
one or more identified high temperature downhole explosives are
selected from PATO, BTX, TPM, ABH, DODECA, Z-Tacot, KHND, and
TPB.
32. The shaped charge made by the process of claim 28, wherein the
one or more identified high temperature downhole explosives are
selected from DIPAM, HNAB, bis-HNAB, HNBP, DPBT, DPPM, HNDS, and
PADP-I.
33. The shaped charge made by the process of claim 28, wherein the
one or more identified high temperature downhole explosives are
selected from NaTNC, HNBIB, TNC, DAT, DADNPO, ONM, ADNBF, DPO, and
PIPA.
34. The shaped charge made by the process of claim 28, wherein the
main body of explosives further comprises one or more other
explosive compounds.
35. The shaped charge of claim 34, wherein the one or more other
explosive compounds are selected from HNS, PYX, and HMX.
36. The shaped charge made by the process of claim 28, wherein the
main body of explosives further comprises one or more of an
energetic material and a fuel.
37. The shaped charge made by the process of claim 28, further
comprising a primer inserted into the case adapted for detonating
the main body of explosive.
38. The shaped charge of claim 37, wherein the primer comprises
NONA.
39. The shaped charge of claim 37, wherein the primer comprises one
or more identified high temperature downhole explosives.
40. The shaped charge of claim 37, wherein the primer is an
explosive compound more sensitive than the one or more identified
high temperature downhole explosives.
41. A method of using one or more high temperature downhole
explosives in a well, the method comprising: (a) providing a
downhole device having one or more identified high temperature
downhole explosives. (b) conveying the downhole device into the
well.
42. The method of claim 41, wherein the identified high temperature
downhole explosives comprise NONA.
43. The method of claim 41, wherein the one or more identified high
temperature downhole explosives are selected from NONA, PENCO, TNN,
T-Tacot, ONT, and TPT.
44. The method of claim 41, wherein the one or more identified high
temperature downhole explosives are selected from PATO, BTX, TPM,
ABH, DODECA, Z-Tacot, KHND, and TPB.
45. The method of claim 41, wherein the one or more identified high
temperature downhole explosives are selected from DIPAM, HNAB,
bis-HNAB, HNBP, DPBT, DPPM, HNDS, and PADP-I.
46. The method of claim 41, wherein the one or more identified high
temperature downhole explosives are selected from NaTNC, HNBIB,
TNC, DAT, DADNPO, ONM, ADNBF, DPO, and PIPA.
47. The method of claim 41, further comprising the step of
combining the one or more identified high temperature downhole
explosives with matter selected from one or more other explosives
and one or more of an energetic material and a fuel.
Description
FIELD OF THE INVENTION
[0001] The subject matter of the present invention relates to
downhole explosives. More specifically, the subject matter of the
present invention relates to explosives for use in downhole wells
for applications requiring performance capability at high
temperature and/or exposures at elevated temperatures for extended
periods of time.
BACKGROUND OF THE INVENTION
[0002] Explosives are used in numerous downhole well applications.
An essential consideration in selecting explosives for use in
downhole applications, such as perforating operations, is that the
explosives have a certain range of time and temperature in which
the explosives are thermally stable. If the explosives are
stretched beyond this range, the explosives start to decompose,
burn, or auto-detonate. Decomposition of explosives generally
reduces their effectiveness and can cause a failure such as a
misfire (a failure to detonate).
[0003] Failures of explosives are costly and often dangerous. For
example, with regard to perforating applications, when a
perforating gun string is lowered to a desired depth but for some
reason cannot be activated, a mis-run has occurred. The mis-run
requires that the perforating gun string be pulled out of the
wellbore and replaced with a new gun string. Such replacement is
both time consuming and expensive. Also, retrieving a mis-fired gun
from a wellbore can be a hazardous operation.
[0004] Because of the time-temperature range considerations
regarding explosives, in the past, use of explosive devices in
downhole applications has, in some instances, been precluded. In
many operations where explosive actuation was desired (i.e., a
device using a frangible member), alternative actuating means were
selected because of the risky nature of the explosives within the
high temperature environment. In order to use explosive devices in
most downhole operations, it is imperative that the operating time
for the explosives be increased for a given temperature.
[0005] There is, therefore, a need for explosive compositions
adapted for use in downhole well applications requiring explosives
that may be exposed to elevated temperatures for extended periods
of time. There is a need for such explosives having improved
thermal stability for use in perforating applications for shape
charges, boosters, detonating cords, and detonators. Additionally,
there is a need for such explosives with improved thermal stability
for use in tubing and casing cutters, explosive-actuated sleeves,
sonic or seismic fracing devices, setting devices, explosive
actuated sliding sleeves, valves or shuttles, breakable or
frangible elements, tubing release devices, and actuating devices,
for example.
SUMMARY OF THE INVENTION
[0006] One embodiment of the present invention provides identified
high temperature downhole explosives for use in downhole well
devices. Such explosives, exhibit thermal stability characteristics
suitable for downhole applications.
[0007] Further scope of applicability of the present invention will
become apparent from the detailed description presented
hereinafter. It should be understood, however, that the detailed
description and the specific examples, while representing a
preferred embodiment of the present invention, are given by way of
illustration only, since various changes and modifications within
the spirit and scope of the invention will become obvious to one
skilled in the art from a reading of the following detailed
description.
BRIEF DESCRIPTION OF THE INVENTION
[0008] A full understanding of the present invention will be
obtained from the detailed description of the preferred embodiment
presented herein below, and the accompanying drawings, which are
given by way of illustration only and are not intended to be
limitative of the present invention, and wherein:
[0009] FIG. 1 is a diagrammatic sketch of a downhole device that is
part of a tool string within a well.
[0010] FIG. 2 is a cross-sectional view of an embodiment of the
present invention for use in a typical shaped charge adapted for
use in a perforating gun.
[0011] FIG. 3 is a cross-sectional view of another embodiment of
the present invention for use in a typical tubing or casing
cutter.
[0012] FIGS. 4a and 4b are cross-sectional views of yet another
embodiment of the present invention for use in a typical tubing
release mechanism.
[0013] FIG. 5 is a diagrammatic sketch of still another embodiment
of the present invention for use in a sonic fracing device.
[0014] FIGS. 6a and 6b are cross-sectional views of another
embodiment of the present invention for use in an explosively set
downhole apparatus. FIG. 6a displays the apparatus prior to
explosive bonding, and FIG. 6b displays the apparatus after
explosive bonding.
[0015] FIGS. 7a-7c are cross-sectional views of another embodiment
of the present invention for use in an apparatus for explosively
opening a production valve.
[0016] FIG. 8 is a cross-sectional view of another embodiment of
the present invention for use in an apparatus for actuating
downhole tools.
DETAILED DESCRIPTION OF THE INVENTION
[0017] In the following detailed description of the subject matter
of the present invention, identified high temperature downhole
explosives are principally described as being used in oil well
applications. Such applications are intended for illustration
purposes only and are not intended to limit the scope of the
present invention. The identified high temperature downhole
explosives can also be used to advantage in operations within gas
wells, water wells, injection wells, and control wells. All such
applications are intended to fall within the purview of the present
invention. However, for purposes of illustration, the identified
high temperature downhole explosives will be described as being
used for oil well applications.
[0018] As shown in FIG. 1, the identified high temperature downhole
explosives are principally described as being used in downhole well
devices that are part of a tool string. The identified high
temperature downhole explosives of the present invention can be
used for any conceivable downhole device/application for which
explosives are suitable. More specifically, the identified high
temperature downhole explosives are particularly suited for
applications requiring high performance capability (i.e., jet
production) combined with thermal stability at high temperature
and/or exposures at elevated temperatures for extended periods of
time. To achieve such performance, the high temperature downhole
explosives are characterized by minimal gas loss caused by exposure
to elevated temperatures for extended periods of time. The
temperature/time suitability or performance ratings of the
identified high temperature downhole explosives provide a
substantial benefit in the ability of tools and equipment to
perform well at elevated temperatures for extended periods of
time.
[0019] One such identified high temperature downhole explosive is
nonanitroterphenyl (NONA). The temperature/time suitability or
performance ratings of explosive components utilizing NONA, for
example, exceed 500.degree. F./1 hour, 460.degree. F./100 hours,
and 420.degree. F./400 hours. Temperature Vacuum Stability Tests
performed on NONA reveal that NONA sustains minimal gas loss at
392.degree. F. even after exposure of approximately 90 days. Thus,
NONA exhibits exceptional thermal stability suitable for downhole
applications.
[0020] Other identified high temperature downhole explosives
exhibiting similar thermal stability qualities include, but are not
limited to, octanitroterphenyl (ONT), pentanitrobenzophenone
(PENCO), tetranitronaphthalene (TNN), tripicryltriazine (TPT), and
tetranitrobenzotriazolo [1,2-a] benzotriazole (T-Tacot).
[0021] Table I to follow provides the results of a Temperature
Vacuum Stability Test for the above mentioned identified high
temperature downhole explosives. The table demonstrates the
temperature/time suitability at a temperature of 200.degree.
Celsius (392.degree. Fahrenheit). Each of the above-mentioned
identified high temperature downhole explosives exhibit exceptional
thermal stability at 200.degree. Celsius. They sustain minimal gas
loss while being exposed to the elevated temperature for extended
period of time.
1TABLE I 200.degree. Temperature Vacuum Stability Tests Time or
exposure (days) 2 7 14 21 28 35 42 49 56 63 70 77 84 91 Total gas
evolved (cm.sup.3/g at STP) NONA .4 .8 1.1 1.6 2.0 2.3 2.8 3.2 3.6
3.9 4.3 4.7 5.1 5.4 ONT .9 1.3 1.4 1.5 1.6 1.7 1.9 1.9 2.0 2.1 2.3
2.4 2.5 2.6 PENCO .1 .2 .3 .4 .6 .6 .6 .7 .7 .9 1.0 1.1 1.2 1.4 TNN
.3 .5 .6 .8 .9 1.0 1.2 1.3 1.4 1.6 1.7 1.8 2.0 2.2 TPT .2 .2 .4 .4
.4 .4 .5 .5 .6 .7 .9 1.0 1.0 1.1 T-tacot .1 .5 .9 1.3 1.6 1.9 2.1
2.5 3.0 3.5 3.9 4.3 4.8 5.3
[0022] The following identified high temperature downhole
explosives exhibit exceptional thermal stability at the elevated
temperature of 175.degree. Celsius (347.degree. F.). Such
identified high temperature downhole explosives include, but are
not limited to, picrylaminotriazole (PATO),
dinitropicrylbenzotriazole (BTX), dodecanitroquaterphenyl (DODECA),
tripicrylmelamine (TPM), axobishexanitrobiphenyl (ABH),
tetranitrobenzotriazolo [2,1-a] benzotriazole (Z-Tacot), potassium
salt of hexanitrodiphenylamine (KHND), and tripicrylbenzene
(TPB).
[0023] Table II to follow provides the results of a Temperature
Vacuum Stability Test for the above mentioned identified high
temperature downhole explosives. The table demonstrates the
temperature/time suitability at a temperature of 175.degree.
Celsius (347.degree. Fahrenheit). Each of the above-mentioned
identified high temperature downhole explosives exhibit exceptional
thermal stability at 175.degree. Celsius. They sustain minimal gas
loss while being exposed to the elevated temperature for extended
period of time.
2TABLE II 175.degree. Temperature Vacuum Stability Tests Time or
exposure (days) 2 7 14 21 28 35 42 49 56 63 70 77 84 91 Total gas
evolved (cm.sup.3/g at STP) PATO .1 .4 .6 .7 .8 .9 1.1 1.2 1.3 1.4
1.4 1.4 1.4 1.5 BTX .2 .3 .4 .4 .5 .6 .7 .8 1.0 1.1 1.1 1.2 1.2 1.3
DODECA .5 .7 .8 .9 .9 .9 1.0 1.0 1.0 1.1 1.2 1.3 1.4 1.4 TPM 1.5
2.0 2.3 2.6 2.9 3.3 3.7 4.1 4.5 4.9 5.2 5.5 5.9 6.7 ABH .4 .7 1.0
1.3 1.6 2.0 2.4 2.7 3.0 3.4 3.7 4.0 4.3 4.7 Z-Tacot .4 .5 .6 .7 .7
.7 .7 .7 .8 .9 1.0 1.1 1.4 1.7 KHND .1 .4 .5 .7 .8 1.0 1.1 1.3 1.4
1.6 1.8 2.0 2.2 2.4 TPB .1 .1 .1 .1 .1 .1 .2 .2 .2 .2 .2 .2 .3
.3
[0024] The following identified high temperature downhole
explosives exhibit exceptional thermal stability at the elevated
temperature of 150.degree. Celsius (302.degree. F.). Such
identified high temperature downhole explosives include, but are
not limited to, dipicramide (DIPAM), hexanitroazobenzene (HNAB),
bis-hexanitroazobenzene (bis-HNAB), hexanitrobiphenyl (HNBP),
dipicrylbenzobiatriazoledione (DPBT), dipicrylpyromellitude (DPPM),
hexanitrodiphenylsulfone (HNDS), and bis [picrylazo]
dinitropyridine (PADP-I).
[0025] Table III to follow provides the results of a Temperature
Vacuum Stability Test for the above mentioned identified high
temperature downhole explosives. The table demonstrates the
temperature/time suitability at a temperature of 150.degree.
Celsius (302.degree. Fahrenheit). Each of the above-mentioned
identified high temperature downhole explosives exhibit exceptional
thermal stability at 150.degree. Celsius. They sustain minimal gas
loss while being exposed to the elevated temperature for extended
period of time.
3TABLE III 150.degree. Temperature Vacuum Stability Tests Time or
exposure (days) 2 7 14 21 28 35 42 49 56 63 70 77 84 91 Total gas
evolved (cm.sup.3/g at STP) DIPAM .2 .4 .5 .5 .6 .7 .7 .8 .8 .9 .9
1.0 1.0 1.0 HNAB .1 .2 .2 .3 .3 .4 .4 .5 .5 .6 .6 .7 .7 .7 bis-HNAB
.5 1.2 1.8 2.5 2.9 3.6 4.2 4.8 5.3 6.0 6.7 7.4 8.1 8.8 HNBP .2 .3
.3 .4 .4 .5 .5 .5 .6 .6 .7 .7 .8 .8 DPBT .4 .7 .9 1.0 1.3 1.5 1.7
1.9 2.1 2.2 2.3 2.4 2.5 2.7 DPPM .3 .7 1.0 1.2 1.4 1.5 1.5 1.6 1.7
1.8 1.9 2.0 2.1 2.2 HNDS .1 .2 .2 .3 .3 .3 .4 .5 .5 .6 .7 .9 1.1
1.3 PADP-I 5.3 4.9 4.3 4.1 3.9 4.1 4.2 4.2 4.3 4.4 4.5 4.7 4.9
5.0
[0026] Other identified high temperature downhole explosives
suitable for downhole use include, but are not limited to, sodium
tetranitrocarbozole (NaTNC), hexanitrobibenzyl (HNBIB), tetranitro
carbazole (TNC), 3,6 diamino 1,2,4,5 tetrazene (DAT),
2,6-diamino-3,5-dinitropyridino-1-oxide (DADNPO), octanitromacro
cycle (ONM), 4,6 dinitrobenzofuroxan (ADNBF),
2,5-dipcryl-1,3,4-oxadiazole (DPO) and m-picrylpicramide
(PIPA).
[0027] It is important to note that although several of the above
identified high temperature downhole explosives have been grouped
according to their thermal stability at particular temperatures,
such grouping is only for the purpose of discussion and not
intended to define the grouped explosives as equivalent to each
other. Although the explosives within the groupings share similar
thermal characteristics, that does not translate into equivalent
suitability for various applications. Other material properties
used in determining suitability for particular applications include
impact sensitivity, density, cost, etc. Such other properties are
not dependent upon the thermal characteristics of a particular
explosive.
[0028] The following examples are illustrative of the numerous
downhole applications for which the identified high temperature
downhole explosives of the present invention are suitable. Such
examples are intended for illustration purposes only and are not
intended to limit the scope of the present invention. The
identified high temperature downhole explosives can be used to
advantage in any downhole application utilizing explosives. All
such applications are intended to fall within the purview of the
present invention.
[0029] Referring to FIG. 2, a typical shaped charge adapted for use
in a perforating gun is illustrated. The perforating gun is adapted
to be disposed in a wellbore. Some shaped charges are discussed in
U.S. Pat. No. 4,724,767 to Aseltine issued Feb. 16, 1988; U.S. Pat.
No. 5,413,048 to Werner et al. issued May 9, 1995; and again in
U.S. Pat. No. 5,597,974 to Voreck, Jr. et al. issued Jan. 28, 1997.
Each of the above mentioned disclosures are incorporated by
reference into this specification.
[0030] In FIG. 2, the shaped charge includes a case 10, a main body
of explosive material 12, which in the past has been, for example,
RDX, HMX, PYX, or HNS packed against the inner wall of the case 10,
a primer 13 disposed adjacent the main body of explosive 12 that is
adapted to detonate the main body of explosive 12 when the primer
13 is detonated, and a liner 14 lining the primer 13 and the main
body of explosive material 12. The shaped charge also includes an
apex 18 and a skirt 16. A detonating cord 20 contacts the case 10
of the shaped charge at a point near the apex 18 of the liner 14 of
the charge. When a detonation wave propagates within the detonating
cord 20, the detonation wave will detonate the primer 13. When the
primer 13 is detonated, the detonation of the primer 13 will
further detonate the main body of explosive 12 of the charge. In
response to the detonation of the main body of explosive 12, the
liner 14 will form a jet 22 that will propagate along a
longitudinal axis of the shaped charge. The jet 22 will perforate a
formation penetrated by the wellbore.
[0031] In accordance with the present invention, it has been
discovered that, when the main body of explosive 12 is comprised of
one or more identified high temperature downhole explosives (NONA,
PATO, BTX, DIPAM, PENCO, TNN, HNAB, TPM, ABH, bis-HNAB, DODECA,
HNBP, Z-Tacot, T-Tacot, DPBT, DPPM, HNDS, KHND, ONT, TPB, TPT,
PADP-I, NaTNC, HNBIB, TNC, DAT, DADNPO, ONM, ADNBF, DPO, or PIPA),
is comprised of a mixture of one or more identified high
temperature downhole explosives and one or more other explosive
compounds, such as HNS, PYX, HMX, or is comprised of one or more
identified high temperature downhole explosives combined/mixed with
one or more of an energetic material and a fuel, and when the
primer 13 is carefully selected to be comprised of a sensitive
explosive material, the shaped charge exhibits exceptional thermal
stability characteristics.
[0032] In the past, the primer 13 had to be comprised of a special
explosive material, other than the explosive material comprising
the main body of explosive 12, because the explosive material
comprising the main body of explosive 12, by itself, was generally
not sensitive enough to be included as part of the primer 13.
Therefore, the primer 13 was comprised of a special (highly
sensitive) explosive material other than the explosive material
comprising the main body of explosive 12 in order for the primer 13
to be detonated. However, in the present invention, identified high
temperature downhole explosives such as DPO have been found to
exhibit sensitivity characteristics suitable for use as the primer
13. Table IV displays the results of an exploding foil initiation
(EFI) test in which DPO was compared with compounds having similar
explosive properties.
4TABLE IV Impact Thermal Stability at 260.degree. C. Sensitivity
Explosive Cc/g/hr. (2 hr.) (cm) DPO 0.6 20 NONA 0.5 39 HNS 0.5 45
2,5-dipicryl-3,4-dinitrofuran 0.8 at 230.degree. C. 23
[0033] As is shown by the data of Table IV, the explosives having
similar thermal stability characteristics as DPO (HNS and NONA),
are not as impact sensitive. Likewise, although
2,5-dipicryl-3,4-dinitrofuran has a similar sensitivity as DPO, it
is not as thermally stable. Thus, DPO has a suitable combination of
thermal stability and sensitivity to be useful not only as a main
body of explosive 12, but also as a primer 13 or booster. One
skilled in the art will recognize that those explosives suitable as
both the main body of explosive 12 and as the primer 13 enable
shape charges to be comprised of a single type of explosive.
[0034] It should be noted, the impact sensitivity of high
temperature downhole explosives is often a function of their
particle size. As an example, by reducing the particle size of a
NONA sample, the impact sensitivity of NONA has been found to be as
low as 18 cm. As a consequence, one skilled in the art will
recognize that NONA of appropriate particle size exhibits thermal
sensitivity characteristics suitable for use as a primer 13 or a
booster.
[0035] FIG. 3 illustrates a typical shaped charge adapted for use
in a tubing or casing cutter. The tubing or casing cutter is
adapted to be disposed in a wellbore for cutting or severing oil
well tubing, drill strings, casings, and the like. Typical tubing
or casing cutters are discussed in U.S. Pat. No. 3,057,295 to
Christopher issued Oct. 9, 1962, U.S. Pat. No. 4,184,430 to Mock
issued Jan. 22, 1980, and U.S. Pat. No. 6,053,247 to Wesson et al.
issued Apr. 25, 2000. Each of the above mentioned disclosures are
incorporated by reference into this specification.
[0036] The shaped explosive charge 30 is mounted within the chamber
32 of the cutter head of the tubing or casing cutter. The shaped
charge includes a booster charge element 34 ignited by a detonating
fuse 36. The ignited booster charge element 34, in turn, detonates
the main explosive charge elements 38 and 40, which produce a
radial jet. The radial jet propagates outwardly to cut the
surrounding tubing or casing.
[0037] In accordance with the present invention, it has been
discovered that, when the main explosive charge elements 38 and 40
are comprised of one or more identified high temperature downhole
explosives, are comprised of a mixture of one or more identified
high temperature downhole explosives and one or more other
explosive compounds, such as HNS, PYX, HMX, or are comprised of one
or more identified high temperature downhole explosives and one or
more of an energetic material and a fuel or an oxidizer, and when
the booster charge element 34 is carefully selected to be comprised
of a sensitive explosive material, the shaped charge exhibits
exceptional thermal stability characteristics.
[0038] As discussed above with regard to the shaped charges used in
perforating guns described with reference to FIG. 2, generally the
booster charge element 34 is comprised of a special (highly
sensitive) explosive material other than the identified high
temperature downhole explosives used for the main explosive charge
elements 38 and 40. However, identified high temperature downhole
explosives such as DPO can be used to advantage as the booster
charge element 34.
[0039] Similar to the tubing or casing cutters, FIGS. 4a and 4b
illustrate a typical tubing release mechanism. The tubing release
mechanism is adapted to be disposed in a wellbore, and more
particularly, connected between a perforating apparatus and a
tubing for shattering a frangible breakup tube thereby
automatically releasing the perforating apparatus from the tubing
in response to a detonation wave passing. A typical tubing release
mechanism is discussed in U.S. Pat. No. 5,293,940 to Hromas et al.
issued Mar. 15, 1994, the details of which are incorporated by
reference into this specification.
[0040] As shown in FIGS. 4a and 4b, when the firing heads 50a and
50b are initiated, a detonation wave is initiated within the
detonating cord 52. The detonation wave 52 propagates through the
firing head adapter 54, transfer housing 56, release piston 58,
frangible breakup tube 60, release mandrel 62, and bottom sub 64,
shooting the perforating gun. When the detonation wave propagating
in the detonation cord 52 passes through the frangible breakup tube
60, the resultant shock wave and pressure from the detonation wave
shatters the frangible breakup tube 60. The breakup tube 60
shatters into small pieces. As a result, the release piston 58 is
no longer supported and held in position by the breakup tube 60.
The pressure force pushing down on the release piston 58 forces the
release piston 58 down into the air chamber 46, which subsequently
causes the release of the perforating gun.
[0041] In accordance with the present invention, it has been
discovered that, when the detonation cord is comprised of one or
more identified high temperature downhole explosives, is comprised
of a mixture of one or more identified high temperature downhole
explosives and one or more other explosive compounds, such as UNS,
PYX, HMX, or is comprised of one or more identified high
temperature downhole explosives and one or more of an energetic
material and a fuel or an oxidizer, the detonating cord 52 exhibits
exceptional thermal stability characteristics.
[0042] FIG. 5 illustrates a sonic fracing mechanism. The tubing
release mechanism is adapted to be disposed in a wellbore, and more
particularly, to increase formation permeability by creating sonic
waves that crack loosen the formation interstices. A typical sonic
fracing mechanism is discussed in U.S. Pat. No. 5,293,940 to Beard
issued Aug. 27, 1985, the details of which are incorporated by
reference into this specification.
[0043] As shown in FIG. 5, the sonic fracing mechanism has a series
of cylinders 70 mounted in a tubular housing 72. An explosive is
contained in a combustion chamber 74 within each cylinder. The
first cylinder is fired, causing an explosion, the shock of which
is transmitted through the ambient fluid into the formation. After
a preselected interval, another cylinder is fired, with slightly
greater shock, and the third firing to follow being greater than
the second. The force of the respective explosions creates a wave
in the formation, which moves outwardly away from the casing until
the force of the explosion is exhausted; then the wave returns
through the formation to the casing, where it will be met by the
next, and greater explosion, creating a greater wave, thus
effecting the washing action clearing passageways for the flow of
production fluid.
[0044] In accordance with the present invention, it has been
discovered that, when the explosive contained within the combustion
chamber is comprised of one or more identified high temperature
downhole explosives, is comprised of a mixture of one or more
identified high temperature downhole explosives and one or more
other explosive compounds, such as HNS, PYX, HMX, or is comprised
of one or more identified high temperature downhole explosives
combined/mixed with one or more of an energetic material and a fuel
or an oxidizer, the combustion chamber exhibits exceptional thermal
stability characteristics.
[0045] FIGS. 6a and 6b illustrate an explosively set downhole
apparatus. Setting apparatus are used for the placement or setting
of borehole apparatus such as packers, casing bore receptacles,
bridge plugs, casing patches, and liner hangers within the casing
of a well bore through the explosive bonding of such apparatus to
the interior of the casing. Typical explosively set downhole
apparatus are discussed in U.S. Pat. No. 4,662,450 to Haugen issued
May 5, 1987, and U.S. Pat. No. 5,447,202 to Littleford, the details
of which are incorporated by reference into this specification.
[0046] Referring to FIG. 6a, detonation of the explosive charge 80
creates a radial shock wave that drives fixation element 82
radially outward into the casing 84, as shown in FIG. 6b . The
fixation element 82 is explosively welded thereto or bonded
therewith the casing 84.
[0047] In accordance with the present invention, it has been
discovered that, when the explosive charge 80 is comprised of one
or more identified high temperature downhole explosives, is
comprised of a mixture of one or more identified high temperature
downhole explosives and one or more other explosive compounds, such
as HNS, PYX, HMX, or is comprised of one or more identified high
temperature downhole explosives combined/mixed with one or more of
an energetic material and a fuel or an oxidizer, the explosive
charge 80 exhibits exceptional thermal stability
characteristics.
[0048] FIGS. 7a-7c illustrate an apparatus for explosively opening
a production valve. More particularly, the figures illustrate an
apparatus adapted to be disposed in a wellbore having a frangible
breakup element that is adapted to shatter into a multitude of
pieces when a detonation wave passes therethrough. A piston is
supported by the frangible breakup element such that when the
frangible breakup element shatters, the piston moves a
predetermined distance, thus opening the production valve. An
example of an apparatus for explosively opening a production valve
is discussed in U.S. Pat. No. 5,318,126 to Edwards et al. issued
Jun. 7, 1994, the details of which are incorporated by reference
into this specification.
[0049] Referring to FIGS. 7a-7c, a detonation cord 90 is disposed
within a series of frangible breakup elements 92 such that a
detonation wave propagated by the detonation cord 90 acts to
shatter the breakup elements 92. Shattering of the elements 92
removes the support for the piston 94 which is then free to move
downwardly in response to either tubing pressure or rathole
pressure or both. Once the piston 94 moves downward a predetermined
distance, the piston acts to open the production valve.
[0050] In accordance with the present invention, it has been
discovered that, when the detonating cord 90 is comprised of one or
more identified high temperature downhole explosives, a mixture of
one or more identified high temperature downhole explosives with
one or more other explosive compounds, such as HNS, PYX, HMX, or
one or more identified high temperature downhole explosives
combined/mixed with one or more of an energetic material and a fuel
or an oxidizer, the detonating cord 90 exhibits exceptional thermal
stability characteristics.
[0051] FIG. 8 illustrates an apparatus for actuating downhole tools
by firing an explosive charge to generate an operating pressure. An
example of an apparatus for explosively actuating downhole tools is
discussed in U.S. Pat. No. 5,316,087 to Manke et al. issued May 31,
1994, the details of which are incorporated by reference into this
specification.
[0052] As further described below, the power piston 106
reciprocates up and down imparting linear movement of the power
mandrel 108 to operate the operating element 110. The operating
element 110 may be of many different varieties corresponding to the
various tools within the testing string. For example, the operating
element 110 may be a rotating ball valve type element of a
formation tester valve having an operating mechanism substantially
like that shown in U.S. Pat. No. 3,856,085 to Holden et al., the
details of which are incorporated herein by reference.
[0053] As another example, the operating element 110 could be a
sliding sleeve valve of a reclosable reverse circulation valve
having an associated operating mechanism substantially like that
shown in U.S. Pat. No. 4,113,012 to Evens et al., the details of
which are incorporated herein by reference.
[0054] The operating element 110 may also be a closing element of
any one of several types of known sampling apparatus. Also, a
multi-mode operating element could be used substantially like that
shown in U.S. Pat. No. 4,711,305 to Ringgenberg, the details of
which are incorporated herein by reference.
[0055] Referring to FIG. 8, a plurality of explosive charges are
contained within the housing 102 and communicated with the upper
and lower power chamber portions 114 and 116. The explosive charges
(118A, 118B, 118C, and 118D) are electrically fired explosive
charges. When any one of the explosive charges 118 is fired, it
generates high temperature, high pressure gases within its
associated power chamber portion 114, 116 which acts to move the
power piston 106 within the power chamber 112.
[0056] In accordance with the present invention, it has been
discovered that, when the explosive charges 118 are comprised of
one or more identified high temperature downhole explosives, are
comprised of a mixture of one or more identified high temperature
downhole explosives and one or more other explosive compounds, such
as HNS, PYX, HMX, or are comprised of one or more identified high
temperature downhole explosives combined/mixed with one or more of
an energetic material and a fuel or an oxidizer, the explosive
charges 118 exhibit exceptional thermal stability
characteristics.
[0057] As discussed above, and as one skilled in the art will
recognize, the identified high temperature downhole explosives that
comprise the subject matter of the present invention can be used in
a great number of downhole applications. In perforating operations,
the identified high temperature downhole explosives can be used not
only as the main body of explosive of the shape charge, but can
also be used for boosters, detonating cords, and detonators, for
example. Additionally, the identified high temperature downhole
explosives of the present invention can also be used to advantage
in applications involving tubing and casing cutters,
explosive-actuated sleeves, valves or shuttles, breakable or
frangible elements, or sonic or seismic source devices, for
example.
[0058] It should be noted that the above discussed application of
use for the identified high temperature downhole explosives of the
present invention are intended for illustration purposes only, and
are not intended as limitations to the scope of the present
invention. One skilled in the art will recognize that the
identified high temperature downhole explosives are not limited in
application. The identified high temperature downhole explosives
are useful in any number of downhole wells and any number of
applications requiring performance capability at high temperatures
and/or exposures at elevated temperatures for extended periods of
time.
[0059] The invention being thus described, it will be obvious that
the same may be varied in many ways. Such variations are not to be
regarded as a departure from the spirit and scope of the invention,
and all such modifications as would be obvious to one skilled in
the art are intended to be included within the scope of the
following non-limiting claims.
* * * * *