Note: Descriptions are shown in the official language in which they were submitted.
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PERFORATING GUN INDEXED WIRING HARNESS
Back~round of the Invention
The present invention relates to perforating guns
for wells, and more particularly to a wiring harness for
selective iring systems for oil and gas well
S perforating guns.
Prior art selective firing systems comnonly
connect the perforating guns to the firing control
system (at the surface of the earth) on a single
conductor, using, typically, an addressing device
downhole which responds to coded signals on the
conductor for selecting the particular gun which is to
be actuated. In the simplest case, the guns are simply
fired in sequence. In more complex systems, provision
is made (such as in a downhole control cartridge) for
controllably addressing specific guns from the
surface. However, the latter usually requires a
plurality of conductors ~"multi-wire" harness system3
for connecting the guns to the control cartridge, with
each gun typically connected to its own unique
controlling wire. (An economical alternative is to use
each wire for controlling two guns by means of "diode
steeringl', in which a firing signal of one palarity
fires one of the guns and the opposite polarity the
other.~
A prîncip~l disadvantage of such a mult;-wire
harness selective firin~ system ls the necessity to
connect each gun to a speciflc ~ire. That is, as the
perforatin~ guns are being assembled on the tool
carrier, they are positioned according to the particular
perforation pattern which is to be effected. The
indîvldual guns are usually identical and dra~Yn from a
co~on inventory, but the electrical conllections are ~7
not O For convenience and efficiency9 the guns are
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elec$rically connected by a series of pre-assembled
wiring harnesses. The harnesses have standardized
mateable connectors on each end for rapid assembly, so
the gun string is assembled by literally plugging the
guns and wiring harnesses into one another. For the
first gun in the string, a wiring harness is selected
having a coupling wire spliced to the electrical harness
conductor representing the first gun; for the second gun
the second harness conductor is spliced; and so forth.
Thus, although the guns themselves may be identical and
interchangeable, the wiring harnesses are not, and
considerable care must be used to be sure that the
correct wirin~ harnesses are used in the proper
sequence. It also means that a large inventory of
wiring harnesses, each unique to a specific position on
the gun string, must be inventoried.
A need thus remains for a multi conductor well
perforating gun selective firing system in which not
only standardi~ed and identical perforating guns, but
~o also standardized and identical wiring harnesses may be
used, to minimize inventory requirements, simplify
assembly of the gun string, and minimize the chances of
miswiring through the inadvertent use of an incorrect
harness at a particular location.
2~ Summary of the Invention
Briefly~ the present invention meets the above
needs and purposes with a multi-conductor well
perforating gun selective iring system in which
identical harnesses are used throughout, each harness
incrementing or indexing the relative positions of the
conductors therein. In a variation in which
diode-steering is used, two harnesses are used, one
which increments and one which does not, since one
conductor will serve for two guns. (Alternatively, a
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single harness fol adjacent pairs of guns could be
proYided.)
Thus, in the preferred embodiment, a vertically
spaced array of selectively actuatable per~orating guns
is assembled on a carrier for subsequent lowering and
positioning within a well bore~ Individual electrical
firing means, typically electrical detonators, are
associated with (attached to) each perforating gun for
individually firing that particular gun. A cable and
downhole control cartridge are connected between the
array o~ guns and a firing control means at the surface
of the earth. The firing control means and downhole
control_cartridge selectively address each of the
individual detonators by providing the proper electrical
signal on the particular conductor of a multi-conductor
wiring harness which connects to the selected
perforating gun. W~ere diode-steering is employed, the
guns may be arranged in subsets, each subset being
connected to a single conductor in the wiring harness.
Where each gun has its own individual conductor, the
subsets may be thought of as consisting of a single gun
eachc
Contrary to the above prior art devices, however 7
the subsets of gun(s) in the array according to this
invention are electrically connected to one another by
identical stepped wiring harness assemblies, one for
each of the subsets. The assemblies are connectable in
series9 ~nd the first or topmost harness is connected to
the downhole control cartridge. In the preferred
embodiment, the assemblies have suitable matching
connectors7 one for receiving the electrical signals and
one for passing or transmitting them on to the next
harness assemblyO The harness assemblies also each have
internal connecting wires arranged to increment the
connectiorls, preferably by one position each, bet~een
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the respective connectors thereon.
In addition, each harness assembly has a coupling
means responsive to an electrieal addressing signal on a
particular connecting wire therein for connecting to and
controllably energizing the electrical detonator
associated with the perforating gun for that particular
harness assembly. As indicated, the harness assemblies
are identical, and thus the coupling means in each
harness assembly is the same? and is connected to the
same particular connecting wire. However, although
connected to the same particular connecting wire in each
harness assembly, the various coupling means in the
series connected harnesses are not connected
electrically to the same terminals in the control
cartridge due to the incrementing of the conductors by
each wiring harness.
Therefore, since each wiring harness electrically
increments all succeeding conductors in the series, the
firing control means at the surface can address the guns
uniquely associated with any one of the identical wiring
harness assemblies by causing the control cartridge to
address the particular electrical conductor in the irst
wiring harness wh;ch, through the series of wiring
harness assemblies, is cumulatively indexed thereto.
It is therefore an object of the present
invention to provide a well perforatlng gun
selective firing syste~ ln ~hich multiple
conductors are individually eonnected to individual
subsets of perforating guns through identical wiring
harness assemblies, one for each subset; in which the
wiring harness assemblies are connectable in series; and in
which each wiring harness assembly increments the
electrical position of the conductors connect d there-
through.
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Thus, in accoxdance with.one broad aspect of the in~ention, there
is provided a wiring harness of the type usea~le in a well per-
forating gun havin~ a spaced array of selectively actuatable
perforating charges which are to be connected to Eiring control
means, said harness comprising two or more identical ~iring
harness assemblies, each including: a) means for connecting
one such assembly to another such wiring harness assembly in a
series configuration, and b) coupling means in each of said har
ness assemblies for connecting a subset of the perforating charges
to the firing control meansO
In accordance with another broad aspect of the inven-
tion there is provided, for use with a well perforating gun
selective firing system including a vertically spaced array of
select;vely actuatable perforating charges, the improvement com-
prising:
a) a wiring harness assembly for each pair of the per-
forating charges, each of said assemblies having a multi-terminal
receiving connector and a corresponding multi-terminal transmitting
connector for connecting said harnesses assemblies to one another
in series configurat~on,
b3 at least one of said harness assemblies having inter-
nal connecting wires arranged to interconnect the terminals of
said transmitting and said receiving connectors and to increment
the connections between the respective terminals of said connectors
thereby translating all succeeding connecting wires coupled to the
terminals of said transmitting connector with respect to the
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terminals of s~aid receiving connector,
c) diode-steering means connected to said harness assem-
blies and responsive to an electrical addressing signal on a pre-
determined connecting wire for controllably energizing, as a
function of the polarity of the addressing signal, a predetermined
one of the perforating charges associated with any one of such
harness assemblies so that the individual charges uniquely assoc-
iated with any one such assem~ly in a series of identical wiring
harness assembl;es can ~e independently addressed by addressing
the particul~r connecting wire which is attached thereto by such
harness assemblies with a signal of predetermined polarity.
In accordance with another broad aspect of the invention
there is provided a well perforating gun selective firing system
comprising:
a3 a vertically spaced array of selectively actuatable
perforating charges,
b) indi~idual firing means associated with each of said
perforating charges, for actuating the particular charge associa-
ted therewith~
c) firing control means for selectively addressing each
said individual firing means,
d) a downhole control cartridge connecting said firing
control means with each of said individual firing means, and
configured for connecting said firing control means to a plurality
of conductors, each conductor representing a predetermined subset
of said perforating charges and associated electrical firing means,
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e) a cable for connecting said downhole control car-
tridge and said ~iring control mea~s r
f) a plurality of identical wiring harness assemblies,
one for each of said subsets of perforating charges~ said assem-
blies being connectable in a series configuration, to furnish
said electrical conductors,
g) each of said harness assemblies having a multi-ter-
minal receiving connector and a corresponding multi-terminal tr~ns-
mitting connector for connecting said assemblies to one another
in said series configuration,
h) coupling means in each of said harness assemblies
having internal connecting wires arranged to interconnect the
terminals of s:aid transmitting and said recei~ingconnectors and
to increment the connections between the respective terminals of
said connectors thexeby translating all succeeding conductors
connected to the terminals of said transmitting connector with
respect to the terminals of said receiving connec-tor such that
said firing control means can address the charges uniquely associa-
ted with any one of said identical wiring harness assemblies by
addressing the particular electrical conductor which is c~ula-
tively indexed by said harness assemblies thereto.
In accordance with another hroad aspect of the inven-
tion thexe is provided a selective firing system for a well
perforat~ng gun having a plurality of spaced explosive charges
which are to be actuated by fixing control means, said system
compris.ing.
two or more identical harness assemblies for electrically
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connecting the charges to the firing control means, wherein each
of said harness assemblies includes (a) a plurali~y of internal
connecting wires one cf which is connectable to a subset of one
or more explosive charges which are to be uniquely associated with
a predetermined harness assembly, and (b) means fo.r translating
the remainincJ connecting wires such that all harness assemblies
ha~e a corresponding connecting ~ire therein ~hich is connectable
to the subset of explosive charges to be associated therewith,
and means for interconnecting said harness assemblies in a series
configuration.
In accorclance with another broad aspect of the invention
there is provided a method for perforating a well comprising:
positioning a spaced array of selectively actuatable explosive
charges at a predetermined location within the well, connecting
the array of charges to firing control means for controlling the
actuation at the charges, wherein this step further comprises:
(a) interconnecting two or more identical wiring harness assemblies
in a series configuration and connecting said assemblies to the
firing control means, (b) provid;ng in each of the assemblies a
unique internal connecting wire for connecting that assembly
to a subset of one or more explosive charges to be associated
therewith and connectincJ that wire to that subset of charges,
(c) providing in each of the assemblies other internal connecting
wires which are translated within the assembly such that each of
the assemblI~s can ha~e a corresponding unique connecting wire
which is connectable to a subset of explosive charges, and
selecti~ely actuatincJ the unique connecting wire associated with
a predetermined subset of charges wi-th the firing control means.
-6b
Brief De~cription of the Drawings
Figure 1 is a somewhat figur~tive illustration of a
well perforatiny gun system;
Figure 2 is a schematic illustration of a first wiring
harness assembly embodiment according to the present invention;
and
Figure 3 illustrates an alternative embodiment similar
to Figure 2~
Description of the Preferred Embodiments
With reference to the drawings, Figure 1 shows a
vertically spaced array 10 of selectively actuatable perforating
guns 12 connected by a downhole control cartridge 14 and cable
15 to a firing control means, such as a control panel 20, located
at the surface o~ the earth. In use~ the array 10 is lowered
on cable 15 into a well boxe~ and when properly positioned by the
cable 15, the var;ous guns 12 are individually actuated to perfor-
ate the well.
In the em~odiment shown in Figure 2, the individual
guns are each fired by individual electrical firing means such
as detonators 250 Thedetonators individually fire the particular
gun associated therewith upon receiving the proper electrical
signal on a coupling wire 30 (Figure 2) connected to the associated
wiring ~arness assembly 35.
The indiv.idual electrical wiring harness
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assemblies 35 are identical~ one for each gun 12. In
order to connect them in series 9 each has a receiving
connector 36 and a complimentary transmitting connector
37. Each harness assembly also has internal connecting
S wires 39 which~ as shown in Fig. 2, increment or advance
the connections between the respective connectors 36 and
37. That is, the wire connected to terminal one on the
receiving connec~or will be connected, for example, to
terminal two on the transmitting connector, and so
forth.
Each wiring harness assembly also has a coupling
means~ such as a wire 40, which is connected to a
particular one of the connecting wires 39, for
responding to an electrical addressing signal on that
particular wire, under the control of the firing control
panel 20 and downhole control cartridge 14, to energize
the detonator 25 associated therewith. Therefore~ due
to the incrementing of the connecting wires 39 by the
harnesses 35, control panel 20 can directly address the
guns 12 individually, even though the coupling means or
wires 40 are identically connected within each of the
identical wiring harness assemblies 35.
The selective ~iring system illustrated in Fig. 3
differs from that of Fig. 2 in that the perforating guns
are generally arranged in subset pairs rather thQn
individuallyO Likewise, the wiring harness assemblies
are arranged in pairs, one an indexed wiring harness 35
as in Fig. 2, and the other a strai~ht-through (non-
incrementing) wiring harness 55. In the preferred
em~odiment, harness 55 includes a pair of diodes 57 for
selectably actuating one of the detonators 25 in the
pair of guns 58a~ 58b energized on the same conductor
line from cartridge 14. The selection depends upon
whether the energiæing signal is positive or negative.
A negative signal will fire gun 5ga by causing current
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to flow in the coupling wire 60 on the straight-through
harness 5S. A positiYe signal will fire gun 58b by
causing current to flow on the coupling means 40
associated with the incrementing wiring harness ~5.
Thus the diode pair 57 in each harness 55 functions as a
steering means between the particular connecting wire 61
to which they are attached in each of the harnesses 55
and the pair of guns connected to be fired thereby.
This provides for selectively energizing the detonators
25 on the gun pairs as a function of the signal which is
ultimately placed on that particular connecting wire 61
under the control of panel 20.
As may be seen, therefore, the present invention
has numerous advantages. Principally7 it is no longer
necessary to stock a large number of harness assemblies,
each unique to a specific gun location. Instead,
identical harness assemblies can be used throughout.
This makes assembly of the perforating gun array much
easier and quicker, and substantially reduces the
likelihood of miswiring. When the harness assembly is
made up of two harnesses, such as harnesses 35 and 55 in
the diode-steering embodiment shown in Fig. 3, the
harness connectors can be polarized, so that the
straight-through wiring harnesses 55 cannot be plugged
directly into one another, but mus~ be connected through
the stepped wiring harnesses 35.
While the forms of apparatus herein described
constitute preferred embodiments of this invention, it
is to be understood that the invention is not limited to
3~ these precise forms of apparatus, and that changes may
be made therein without departing from the scope of the
nventlon.
