U.S. patent application number 15/615553 was filed with the patent office on 2018-12-06 for electromechanical assembly for routing electrical signals in guns for well perforation.
The applicant listed for this patent is Sergio F. Goyeneche. Invention is credited to Sergio F. Goyeneche.
Application Number | 20180347325 15/615553 |
Document ID | / |
Family ID | 64459337 |
Filed Date | 2018-12-06 |
United States Patent
Application |
20180347325 |
Kind Code |
A1 |
Goyeneche; Sergio F. |
December 6, 2018 |
Electromechanical Assembly for Routing Electrical Signals in Guns
for Well Perforation
Abstract
An electromechanical switch for use in well perforating gun
assemblies wells comprising an initial pass-through configuration
where the switch passes an electrical connection from a shooting
line through the switch's plunger to the neighboring gun until a
pressure event acts on the switch causing the shooting line to
disengage from the neighboring gun and connect to the internal
detonator for subsequent firing sequence to trigger detonation.
Inventors: |
Goyeneche; Sergio F.;
(Spring, TX) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Goyeneche; Sergio F. |
Spring |
TX |
US |
|
|
Family ID: |
64459337 |
Appl. No.: |
15/615553 |
Filed: |
June 6, 2017 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
E21B 43/11855 20130101;
E21B 43/119 20130101 |
International
Class: |
E21B 43/1185 20060101
E21B043/1185; E21B 43/119 20060101 E21B043/119 |
Claims
1. An electromechanical switching assembly comprising: a switch
body having a first contact for electrically connecting to a
shooting line; the first contact being slideably mounted within the
switch body and being electrically connected to a second contact,
the second contact being slideably mounted within the switch body
and protracted from one end of the switch body forming a plunger
sensitive to pressure of a predetermined threshold; pressure
causing the second contact to retract into the switch body,
transferring movement to the first contact which disengages from
the second contact and electrically connects to a third
contact.
2. The assembly of claim 1 wherein the first contact has a
compression spring extending to the second contact to maintain
electrical connection between the two contacts.
3. The assembly of claim 1 wherein the second contact is encircled
by a flexible/compressible O-ring fitting inside one end of the
switch body and preventing leakage therebetween.
4. The assembly of claim 3 wherein the second contact is encircled
by a second flexible/compressible O-ring fitting inside one end of
the switch body behind and spaced apart from the first O-ring and
preventing leakage therebetween.
5. The assembly of claim 1 wherein the second contact is urged by a
spring toward the third contact, the spring held in a compressed
state until the threshold pressure is applied.
6. The assembly of claim 5 wherein the spring is held in a
compressed state by a threaded portion of the contact screwed to
the housing of the switch, the threads breaking under the threshold
pressure and freeing the first contact to be moved by the
spring.
7. The assembly of claim 5 wherein the spring is held in a
compressed state by a beveled portion of the second contact being
greater than the inside of the switch body and mating with a
beveled opening at one end of the switch body.
8. A method of electrically connecting a plurality of perforating
gun assemblies wherein a shooting line is connected to a switch in
the first gun, the switch being configured to pass an electrical
signal from the shooting line to the second gun's shooting line
through a plunger; the plunger reacting to pressure from an
explosion in the second gun, disconnecting the shooting line from
the second gun and an internal spring urging the shooting line to
connect to the first gun's internal detonator.
9. The method as described in claim 8 wherein the plunger comprises
a compression spring between the shooting line and the back end of
the plunger to ensure electrical contact until the pressure
reaction.
10. The method as described in claim 8 wherein the plunger
comprises a threading joint holding a spring in compression until a
pressure threshold breaks away the thread allowing the spring to
reconnect the shooting line to the first gun's detonator.
Description
BACKGROUND OF THE INVENTION
Field of the Invention
[0001] This invention refers to an electro-mechanical switch
assembly for routing electrical signals in a plurality of well
perforating guns ("guns"). This switch assembly isolates a single
gun's explosive detonator from a common firing signal line shared
by the plurality of guns until mechanical action from a neighboring
gun causes a switching action removing the isolation thus preparing
the gun to trigger on a following fire signal.
[0002] This process of well perforation consists of the perforation
of the metallic casing of a well, of isolating cement surrounding
the casing, and of the layers of rock in the producing formation by
means of explosives housed within perforating guns; achieving,
through bore holes produced by a plurality of charges, a connection
between the depths of the producing zone and the interior of the
well. While this invention is generally found in the petroleum
production industry, it may be equally applied to other
environments where perforation of well casing into the surrounding
environment is necessary, such as water wells.
Background of the Invention
[0003] The perforation of producing wells is realized by lowering
into the well a perf assembly comprised of a plurality of guns each
containing a plurality of charges. The guns are connected end to
end and wired in sequence to a firing circuit on the surface of the
by intermediate subs containing pass through openings for wiring. A
firing wire, coupled with the casing as a ground, carries an
electrical signal through the well bore to connect with each gun
and allow firing of the detonators
[0004] One method of independently firing the guns is to use
individually addressable detonators such as those described in U.S.
Pat. No. 8,091,477 and U.S. Pat. No. 8,230,788. Another method of
independently firing the guns is to connect each gun through a
pressure sensitive switch which grounds the detonator of each gun
until the pressure of the previous gun's firing triggers the switch
to an active state.
[0005] Diodes are used to cause each gun to require a polarity
reversal from the signal which fired the previous gun. This
prevents the signal from propagating throughout the assembly as the
blasts set each pressure switch sequentially, and the pressure
switches prevent the later guns from firing before the previous
ones. This method requires a continuous electrical signal to run
the length of the perf assembly.
[0006] The preferred method is to fire the farthest/lowest gun
first. Then, sequentially fire each gun back toward the well
opening. This is because the explosion/pressure/debris from the
gun's firing can possibly damage adjacent guns. Wires can break or
connectors can loosen during shockwave vibrations, or by blast
force. With pressure switches, any damage retrieval of the perf
assembly for correction, as the rest of the assembly is now
non-fireable.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] FIGS. 1A and B are wiring diagram of a press before and
after experiencing a mechanical pressure action.
[0008] FIGS. 2A and B show a cross section of a common pressure
switch currently used in the industry.
[0009] FIGS. 3A and B show cross sections a push spring pressure
switch in accordance with an exemplary embodiment of the
innovation.
[0010] FIGS. 4A and B show cross sections a pull spring pressure
switch in accordance with an exemplary embodiment of the
innovation.
DETAILED DESCRIPTION OF THE INVENTION
[0011] the purpose of the pressure switch is to allow a single fire
signal wire to control a plurality of guns in a managed sequence.
This is accomplished by integrating a pressure switch into each
gun's detonation line. The switch passes the fire signal along to
the next gun in the sequence so that only the last/farthest/lowest
gun in the sequence response to the signal by detonating.
[0012] The detonation of the lowest gun in the sequence causes a
mechanical pressure on the neighboring gun which changes the
position of the pressure switch so that the switch no longer passes
the fire signal along, but instead routes it internally to the
detonator. A diode connected in series with the detonator prevents
the fire signal from propagating through all the guns by requiring
each gun to use a reverse polarity signal from the neighboring
guns.
[0013] The applicant has improved switch designs by introducing
extra protection for the interior of the switch so that debris from
the neighboring explosions do not foul electrical contacts. Locking
components ensure the switch stays in an initial pass-through
configuration until significant pressure is applied, and the
integration of springs bias the switch to an internal routing
configuration once triggered to ensure it remains in a desired
position. Additionally, compression springs between the toggle and
the piston ensure a reliable electrical contact for the switch's
pass-through configuration.
DETAILED DESCRIPTION OF THE DRAWINGS
[0014] FIGS. A and B are wiring diagram of a pressure switch before
and after experiencing a mechanical pressure action. FIG. 1A is a
wiring diagram of a switch (100) in an initial configuration. The
toggle (140) extends from the common point C to connect to point A.
This is the pass-through configuration so the fire signal from the
shooting line (110) leading to the surface passes through to the
next gun via the down-hole contact (120).
[0015] FIG. 1B is a wiring diagram of the same switch (100') after
a pressure event. Pressure from an explosion in the neighboring gun
(to the right) causes the piston (150) to move the toggle (140)
from point A to point B. The toggle (140) extends from the common
point C to connect to point B. This is the internal routing
configuration. So the fire signal from the shooting line (110) from
the surface is now routed to the local gun (130). A diode (133)
wired in series blocks the fire signal from reaching the detonator
line (135) until the proper polarity is supplied.
[0016] FIGS. 2A and B show a cross section of a common pressure
switch currently used in the industry. In a normal industry
pressure switch (200) the toggle (140) is actually a metallic slide
held by insulating material (230) against the piston (150) which is
also metallic and acts as the pass-through connection (120) to the
neighboring gun. The piston (150) is secured in an ended position
(210) with a plastic sleeve (155) and an O-ring (220).
[0017] FIG. 2B shows the desired position of the switch components
after pressure is applied to the piston (150). The piston is pushed
back (210') to a new position and causes the toggle (140) to
separate and contact point B, a metallic sleeve. This completes the
electrical circuit of the shooting line (110) to the local gun
(130) so the fire signal will be routed to the diode (133) and the
detonator (133).
[0018] However, problems can develop if the toggle (140) is not
sufficiently contacting the pass-through contact/piston (120/150)
because the fire signal will not be conducted to the downhole guns,
resulting in a misfire. If the pressure does not produce sufficient
force to move the toggle (140) back into the pressure switch body
to connect with the metallic sleeve (B), or mechanically bounces
off the bottom of the switch, the toggle can fail to maintain
contact with the local gun (Point B) resulting in a misfire.
[0019] FIG. 3A and B show cross sections of a push spring pressure
switch in accordance with an exemplary embodiment of the
innovation. In this configuration, the plastic sleeve (155)'s
O-ring (220) is supplemented with a second O-ring (320). The double
O-ring configuration causes a pressure reduction the secondary
O-ring by the shielding of the first O-ring reducing the chance of
contaminating water and debris from entering the switch's inner
compartment. A beveled edge (310) provides an additional level of
protection because light pressure forces the bevel closed until the
point of failure where the bevel ring snaps away from the plastic
sleeve causing an outward force away from the O-rings.
[0020] The toggle (140) has a spring (330) at the top end to
maintain contact with the piston (150) when the toggle is in the
initial position to prevent misfire. Internal threads (340) hold
the toggle in the initial position so that the pass-through
connection is assured. Pressure from an explosion in the
neighboring gun (to the right) causes the piston (150) to move with
the triggering force necessary to break the bevel ring (310) of the
plastic sleeve and the internal threads (340) of the toggle.
[0021] An internal spring (350) biases the toggle to move from
point A (not indicated) to point B. The toggle (140) in the
internal configuration holds the electrical contact (point B)
against the internal pressure ring (360). This internal routing
configuration is held by the internal spring (350) against later
shifting or bounce so the fire signal from the shooting line (110)
from the surface is now reliably routed to the local gun (130) and
misfire is prevented.
[0022] FIGS. 4A and B show cross sections of a pull spring pressure
switch in accordance with an exemplary embodiment of the
innovation. In the alternative configuration, the internal spring
(370) is secured in an extended configuration to one end of the
switch (380) so it creates a pulling force to urge the toggle (140)
away from the internal threads (340) and disengage the spring
connecting the toggle (140) to the piston (150). The internal
spring (370) provides sufficient tension to ensure the toggle (140)
remains in contact with the electrical contact (point B) by
pressing against the internal p g (360). This internal routing
configuration is held by the internal spring (370) against later
shifting or bouncing so the fire signal from the shooting line
(110) from the surface is not reliably routed to the local gun
(130) and misfire prevented.
[0023] As in the previous embodiment, the toggle (140) has a spring
(330) at the top end to maintain contact with the piston (150) when
the toggle is in the initial position to prevent misfire. Internal
threads (340) hold the toggle in the initial position so that the
pass-through connection is assured. Pressure from an explosion in
the neighboring gun (to the right) causes the piston (150) to move
with the triggering force necessary to break the bevel ring (310)
of the plastic sleeve and the internal threads (340) of the
toggle.
[0024] In the preferred embodiments the plastic utilized is a
thermoplastic polymer called Polyether ether ketone (commonly
referred to as PEEK) due to its resistance to harsh chemicals and
mechanical strength as well as a hydrolysis resistance to the
watery environment normally found in drilling. One skilled in the
arts would appreciate that other materials of plastic, glass, or
metal may be utilized as well as different mechanical configuration
such as sheer points or break-aways for the threads and bevel to
determine the breaking points necessary to trigger the switch at
the desired pressures.
[0025] The diagrams in accordance with exemplary embodiments of the
present invention are provided as examples and should not be
construed to limit other embodiments within the scope of the
invention. The above discussion is meant to be illustrative of the
principles and various embodiments of the present invention.
Numerous variations and modifications will become apparent to those
skilled in the art once the above disclosure is fully appreciated.
It is intended that the following claims be interpreted to embrace
all such variations and modifications.
* * * * *