Ammunition and explosives – Igniting devices and systems – Fuse cord
Reexamination Certificate
2000-04-11
2003-09-23
Carone, Michael J. (Department: 3641)
Ammunition and explosives
Igniting devices and systems
Fuse cord
C102S275600, C102S275700, C102S275800, C102S275500
Reexamination Certificate
active
06622630
ABSTRACT:
BACKGROUND
The invention relates to a booster, such as a booster that is used to transfer a detonation train between two detonating cords, for example.
A perforating gun typically is used to form tunnels in a formation to enhance the production of oil and/or gas from the formation. The tunnels are formed by detonating shaped charges of the perforating gun. In this manner, the shaped charges typically detonate in response to a shockwave, or detonation train, that propagates along a detonating cord (often called a primer cord) that contacts the shaped charges. Quite often, several perforating guns may be used to perforate the formation(s) of a wellbore in one firing sequence. As a result, the detonation train may be relayed from one perforating gun to the next, a condition that implies the detonation train is relayed between the detonating cords of the different perforating guns. One way to accomplish this is to tie the ends of the detonating cords together. However, such an arrangement may be too susceptible to failure.
Secondary explosives may be used to more effectively transfer a detonation train between two detonating cords, as the secondary explosives amplify, or boost, the detonation train due to the nature of the transfer. For example, referring to
FIG. 1
, a pair of detonating boosters
10
(a donor booster
10
a
and a receptor booster
10
b
) use secondary explosives to transfer a detonation train from one detonating cord
12
to another detonating cord
14
. To accomplish this, the detonating booster
10
may include an explosive
20
that is located near a closed flat end
24
of a tubular shell
22
. An open end
21
of the shell
22
receives an end of the detonating cord
12
,
14
that ideally contacts the explosive
20
. The explosive
20
in the donor booster
10
a
detonates in response to a detonation train from the detonating cord
12
, an event that causes the end
24
of the shell
22
to break into several projectiles. If the receptor booster
10
b
is close enough to the donor booster
10
a
, the projectiles strike the end of the receptor booster
10
b
and detonate its explosive
20
. The detonation of the explosive
20
of the receptor booster
10
b
, in turn, introduces a detonation train to the detonating cord
14
to complete the transfer of the detonation train. As depicted in
FIG. 1
, the donor
10
a
and receptor
10
b
boosters may be identical. Due to this feature, either booster
10
may be used as the donor booster, thereby making it difficult to make errors when assembling the donor and the receptor boosters
10
. Not shown in
FIG. 1
is a housing that typically is used to hold and position the donor
10
a
and receptor
10
b
boosters.
Due to the tolerances of other parts of the perforating gun (e.g., tolerances introduced by loading tube for shaped charges, connections, booster housing, etc.), it is difficult to have a fixed booster-to-booster air gap
40
between the ends
24
of the donor
10
a
and receptor
10
b
boosters. Because the projectiles from the donor booster
10
a
tend to spread apart during flight, the success of the detonation train transfer may be sensitive to the span of the air gap
40
. Therefore, if the air gap
40
is too large, the projectiles may spread too far apart and not sufficiently contact the receptor booster
10
b
to cause detonation of its explosive
20
.
Referring to
2
, the success of the detonation train transfer may also be sensitive to a cord-to-booster air gap
43
that may exist between the end of the detonating cord
12
,
14
and the explosive
20
. This gap
43
may be attributable to, as examples, an uneven cut in the detonating cord
12
,
14
or assembly error. Unfortunately, if the span of the air gap
43
is too large, the detonation train transfer may fail. For example, for the donor booster
10
a
, if the span is too large, a detonation train from the detonating cord
12
may not detonate the explosive
20
, and for the receptor booster
10
b
, if the span is too large, the detonation of the explosive
20
may not initiate a detonation train on the detonating cord
14
.
Thus, there is a continuing need for an arrangement that addresses one or more of the above-stated problems.
SUMMARY
In one embodiment of the invention, a booster to relay a detonation train from a detonating cord to another booster includes an explosive and a shell. The shell has an open end to receive an end of the detonating cord and an indented closed end that is adapted to form a projectile to strike said another booster when the explosive detonates.
In another embodiment of the invention, a booster to relay a detonation train from a detonating cord to another booster includes a shell and an explosive. The shell is adapted to receive an end of the detonating cord, and the explosive is adapted to detonate in response to the detonation train. The explosive includes at least approximately fifty percent of NONA by weight, and the explosive forms at least one projectile out of the shell to strike the other booster when the explosive detonates.
Other features will become apparent from the following description, from the drawings and from the claims.
REFERENCES:
patent: 2535518 (1950-12-01), Rich
patent: 2618221 (1952-11-01), Lowe
patent: 2923239 (1960-02-01), Andrew et al.
patent: 4735145 (1988-04-01), Johnson et al.
patent: 4998477 (1991-03-01), Barker
patent: 5503077 (1996-04-01), motley
patent: 5631440 (1997-05-01), Thureson et al.
patent: 6047643 (2000-04-01), Benner et al.
patent: 6397752 (2002-06-01), Yang et al.
patent: 257 649 (1925-05-01), None
patent: 579 281 (1946-07-01), None
patent: 708 422 (1954-05-01), None
patent: 2 246 620 (1992-02-01), None
patent: WO 90/07689 (1990-07-01), None
Behrmann Lawrence A.
Mai Jason H.
Yang Wenbo
Griffin Jeffery E.
Jeffery Brigitte L.
Schlumberger Technology Corporation
Semunegus Lulit
Trop Pruner & Hu P.C.
LandOfFree
Booster does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Booster, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Booster will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3020393