CANON DE PERFORATION A TROUS DE TIR SE REFERMANT AUTOMATIQUEMENT

PERFORATION GUN HAVING SELF-CLOSING PENETRATION HOLES

Abrégé français

L'invention concerne un canon de perforation comportant un tube de canon extérieur à l'intérieur duquel est logé un tube intérieur de façon coaxiale, le tube intérieur portant des perforateurs pouvant être amorcés au moyen d'un cordeau détonant s'étendant à travers le tube de canon, les perforateurs perforant par ailleurs le tube de canon après amorçage afin de former des trous de tir. Des éléments sont prévus pour la fermeture automatique des trous de tir après le tir, ces éléments se présentant sous la forme d'un fluide gonflant. L'invention vise à obtenir un fluide gonflant nécessitant un espace réduit dans le canon de perforation et pouvant être intégré aisément dans le canon de perforation. A cet effet, le fluide gonflant est disposé sous forme plane à l'intérieur du canon de perforation.

Abrégé anglais

The invention relates to a perforating gun having an outer gun barrel, inside of which an inner barrel is coaxially arranged, carrying perforators that can be ignited by means of a detonating cord leading through the gun barrel and, after ignition, pierce the gun barrel in order to form penetration holes, wherein means are provided for automatically closing the penetration holes after the blast, said means being a swellable medium. In order to ensure that the swellable medium requires little space in the perforating gun and can be easily integrated into the perforating gun, according to the invention the swellable medium is disposed in a laminary manner inside the perforating gun.

Revendications

5
Claims
1. Perforation gun having an outer gun barrel inside of which an inner barrel
is coaxially situated, and which bears perforators that are ignitable via a
detonating fuse leading through the gun barrel and which after ignition
pierce the gun barrel to form penetration holes, wherein a means is
provided for automatically closing the penetration holes after the shot,
and this means is a swellable medium, characterized in that the swellable
medium is situated in a planar manner inside the perforation gun.
2. Perforation gun according to Claim 1, characterized in that the swellable
medium is provided as a coating in the perforation gun.
3. Perforation gun according to Claim 2, characterized in that the coating is
situated on the interior of the gun barrel.
4. Perforation gun according to Claim 2, characterized in that the coating is
situated on an additional thin-walled pipe which is located coaxially
between the outer gun barrel and the inner barrel.
5. Perforation gun according to Claim 1, characterized in that the swellable
medium is applied as a solid material, for example supplied from a roll by
wrapping, to the gun barrel or an additional thin-walled pipe which is
located coaxially between the gun barrel and the inner barrel.
6. Perforation gun according to one of the preceding claims, characterized
in that the swellable medium is applied only in the region of the
penetration holes as a solid material, for example as a circular blank, to

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the gun barrel and/or an additional thin-walled pipe which is located
coaxially between the gun barrel and the inner barrel
7. Perforation gun according to Claim 1, characterized in that the swellable
medium itself is a pipe or tube which is located coaxially between the
outer gun barrel and the inner barrel.
8 Perforation gun according to one of the preceding claims, characterized
in that the swellable medium is activated by the ignition of the perforators
via contact with the borehole medium such as oil, gas, water, drilling
fluids used in deep hole drilling, or by other borehole-related influences,
swells up, and thus closes the penetration holes.
9 Use of a swellable planar medium inside a perforation gun, having an
outer gun barrel inside of which an inner barrel is coaxially situated, and
which bears perforators that are ignitable via a detonating fuse leading
through the gun barrel, and which after ignition pierce the gun barrel to
form penetration holes, wherein the swellable medium is activated by the
ignition of the perforators via contact with the borehole medium such as
oil, gas, water, drilling fluids used in deep hole drilling, or by other
borehole-related influences, swells up, and thus closes the penetration
holes.
Use according to Claim 9, characterized in that the swellable medium is
provided as a coating in the perforation gun
11. Use according to Claim 9, characterized in that the swellable medium is
applied as a solid material by wrapping

7
12 Use according to Claim 9, characterized in that the swellable medium
itself is a pipe or tube which is located coaxially between the outer gun
barrel and the inner barrel.

Description

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Perforation gun having self-closing penetration holes
The invention relates to a perforation gun having an outer gun barrel inside
of
which an inner barrel is coaxially situated, and which bears perforators that
are ignitable via a detonating fuse leading through the gun barrel, and which
after ignition pierce the gun barrel to form penetration holes, wherein a
means
is provided for automatically dosing the penetration holes after the shot, and
this means is a swellable medium.
Such a perforation gun is described in EP 1 685 308 B1.
Perforation guns are.used in deep hole blasting in the crude oil and natural
gas industry as. well as in hydraulic engineering to tie the borehole to the
storage horizon. The borehole generally contains a drill hole fluid, which may
be an introduced fluid or the medium to be conveyed from the surrounding
rock.
A perforation gun is composed of an outer gun barrel, inside of which
perforators, usually hollow or projectile charges, are situated, and which
shoot radially outwardly through the gun barrel in the case of ignition. The
hollow charges are usually supported by a thin-walled support pipe which
extends coaxially inside the gun barrel. Penetration holes remain in the gun
barrel after the shot.
A problem with this method is that residual pieces and fragments of the
perforators and of the components inside the gun barrel may fall into the
borehole through the penetration holes after the shot. For this reason, as
described in EP 1 685 308, means are provided for automatically closing the
CONFIRMATION COPY

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penetration holes after the shot, these means being cartridges containing a
swellable two-component foam. These cartridges are situated in the gun
barrel, and break up by means of the ignited detonating fuse, as the result of
which foam emerges from the cartridges, swells up, and plugs the penetration
holes.
The object of the invention is to improve a perforation gun according to the
preamble of Claim 1 in such a way that the swellable medium requires little
space and is easily integratable into the perforation gun. In one embodiment,
it is the further aim that preferably no additional room is taken up in the
perforation gun.
This object is achieved according to the invention in that the swellable
medium is situated in a planar manner inside the perforation gun. Planar
structures require less space, and are easily integratable into the
perforation
gun.
In one preferred embodiment, the swellable medium is provided as a coating
in the perforation gun. A coating requires no additional room in the
perforation
gun, and therefore is easily integratable.
The coating is preferably situated on the interior of the gun barrel.
Alternatively, the coating may be applied to an additional thin-walled pipe
located coaxially between the outer gun barrel and the inner barrel. Both
barrels are particularly suitable for a coating.
In another embodiment, the swellable medium is applied as a solid material,
for example supplied from a roll by wrapping, to the gun barrel or an

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additional thin-walled pipe which is located coaxially between the gun barrel
and the inner barrel. Wrapping is a simple manual activity which is also cost-
effective.
The swellable medium may also be applied only in the region of the
penetration holes as a solid material, for example as a circular blank, to the
gun barrel and/or an additional thin-walled pipe which is located coaxially
between the gun barrel and the inner barrel. Circular blanks are easily
manufactured and applied.
In another preferred embodiment, the swellable medium itself is a pipe or
tube which is located coaxially between the outer gun barrel and the inner
barrel.
In all embodiments, the swellable medium may be activated by igniting the
perforators via contact with the borehole medium such as oil, gas, water,
drilling fluids used in deep hole drilling, or by other borehole-related
influences, whereby the swellable medium swells up and thus closes the
penetration holes.
In one preferred embodiment, the swellable medium is composed of an
elastomer compound which is activated on contact with, for example,
= oil
= gas
= other types of hydrocarbons
= water
= borehole drilling fluids used in deep hole drilling
= explosive gases from perforators,

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and swells up, thus plugging the penetration holes.
The swellable medium may also be activated by matching the gun internal
pressure to the pressure present in the borehole, which is generally much
higher. This is achieved by properly penetrating the gun outer wall by means
of the perforators which are ignited in the gun.
It is preferred to use a swellable planar medium inside a perforation gun
having an outer gun barrel inside of which an inner barrel is coaxially
situated,
and which bears perforators that are ignitable via a detonating fuse leading
through the gun barrel, and which after ignition pierce the gun barrel to form
penetration holes, wherein the swellable medium is activated by the ignition
of the perforators via contact with the borehole medium such as oil, gas,
water, drilling fluids used in deep hole drilling, or by other borehole-
related
influences, swells up, and thus closes the penetration holes.
The swellable medium may be provided as a coating in the perforation gun,
applied as a solid material by wrapping, or may be a pipe or tube itself
which'
is located coaxially between the outer gun barrel and the inner barrel.
The invention is characterized in that no "debris" (fragments from the
perforators) falls into the borehole. No external intervention is necessary to
close the penetration holes.