EP4190935A1 - Perforation gun tube and perforation gun - Google Patents

Abstract

The present invention relates to a perforating gun barrel, which is characterized in that the barrel consists of a steel alloy which, in addition to iron, includes the following alloying elements, specified in percent by mass: C 0.12 - 0.22% Si 0.3 - 1.0 %Mn 1.0 - 4%Cr 0.5 - 2%Mo 0.1 -1%, V 0.05 -0.2%Ti 0.02 - 0.1% and B 0.001 - 0.01% and smelting related impurities and that the tube has a yield strength, R_P0.2, in the range of 750 to 1100 MPa. In addition, a perforation gun with such a perforation gun barrel is described.

Description

The present invention relates to a perforating gun barrel and a perforating gun having a perforating gun barrel.

Perforating guns, also known as perforating guns or perfguns, are used to activate wells for oil and gas production. The surrounding rock in the borehole is destroyed by means of a targeted blast in order to become more permeable for the fluid, i.e. oil or natural gas. The outer tube of the perforation gun is also referred to as a hollow carrier. The outer tube has the task of holding the perforation gun during the blast and must not be destroyed or significantly deformed in order to prevent the borehole from becoming blocked. This requires the outer tube material to be highly resistant to the extreme loads.

The object of the present invention is therefore to create a perforation gun and in particular a perforation gun barrel that reliably withstands these loads.

According to a first aspect, this object is achieved by a perforation gun tube, which is characterized in that the tube consists of a steel alloy which, in addition to iron, includes the following alloying elements, specified in percent by mass: C 0.12-0.22% si 0.3-1.0% Mn 1.0-4% Cr 0.5 - 2% Mon 0.1 - 1%, V 0.05-0.2% Ti 0.02-0.1% and B 0.001 - 0.01% and melting impurities, and that the tube has a yield strength, R _P0.2 , in the range of 750 to 1100 MPa.

The perforating gun barrel is also known as the barrel. The steel alloy is also referred to below as a material or alloy. Contents of alloying elements are given in percent by mass, but are only referred to as percent if necessary. Impurities caused by smelting are unavoidable impurities that occur during the production of the alloy.

According to the invention, a tube of a perforation gun is referred to as a perforation gun tube. In particular, the perforation gun tube preferably represents the outer tube of a perforation gun and can also be referred to as a hollow carrier. In the following, the perforation gun is also referred to as a perfgun or perforating gun. The tube is preferably produced seamlessly from a solid billet or hollow billet, for example by a conventional push bench process or the known Mannesmann rolling process and, if necessary, stretch-reducing rolling.

The pipe according to the invention has a yield strength R _P0.2 of at least ₇₅₀ MPa, in particular in the range from 800 to 1100 MPa. Preferably _, the tube has a yield strength, R _P0.2 , in the range of 850 to 1050 MPa. These yield point values can be achieved with the material used according to the invention. Thus, the invention increases the resistance of the alloy and thus of the pipe to failure under highly dynamic loads, especially achieved during the explosion. In addition, the tube preferably has a high strength sufficient to withstand the ambient pressure of the PerfGun prior to detonation.

The pipe preferably has a tensile strength R _m of at least 1100 MPa, preferably up to a maximum of 1400 MPa.

Preferably, the tube has a yield strength ratio R _e /R _m of less than 0.9, preferably less than 0.87, more preferably 0.8 or 0.7.

The tube preferably has an elongation at break of more than 10%, preferably more than 16%.

The tube preferably has an air-hardened, bainitic structure. As a result, the perforation gun barrel has properties that take into account the stresses on the perforation gun. Advantages compared to conventionally tempered perforation gun barrels are the reduced energy consumption due to the saved heat treatment steps of hardening and tempering.

A structure which has at least 70 percent by area of bainite is preferably referred to as a bainitic structure. The structure can also have martensite, austenite and/or ferrite. The tube according to the invention is preferably hardened after a heat treatment in air. A cooling rate of 4 to 6 K/s, preferably 5 K/s, is preferably used here.

Preferably, after air quenching, the tube has been subjected to at least one cold forming step. As a result, the dislocation density can be increased. The cold forming preferably represents a straightening of the tube. In this way, in particular, the yield point of the perforation gun tube can be further increased.

The perforating gun tube can have several, in particular locally limited, sections of reduced wall thickness, which serve as predetermined breaking points. These locally limited sections are preferably punctiform or circular sections. The tube preferably has at least one predetermined breaking point in the form of a reduced wall thickness. In particular, the predetermined breaking point can be a round indentation on the outside or the inside of the tube. The locally limited sections, ie the predetermined breaking points, are provided in the perforation gun barrel to form wall openings on the perforation gun barrel when ignition charges introduced into the perforation gun barrel are ignited. Due to the high energy absorption capacity of the steel alloy according to the invention, from which the perforating gun barrel is made, it can be ensured when the ignition charges are ignited that the perforating gun barrel does not burst. Only the areas of reduced wall thickness are severed, allowing the surrounding rock to be perforated.

In the alloy according to the invention, carbon is present in a range between 0.12 and 0.22% by mass. Carbon ensures hardening of the material. If the carbon content is too low, ie if it is below 0.12% in particular, the strength of the alloy is too low, ie the strength required for the stresses of a perf gun cannot be achieved. On the other hand, if the carbon content is too high, i.e. if it is over 0.22% by mass, the weldability of the material and thus of the PerfGun made from the material is impaired. With the carbon contained according to the invention, a strength of the material can also be achieved in which the addition of expensive alloying elements, such as molybdenum, can be sufficient to increase strength, even in small amounts. In one embodiment, the carbon content of the alloy is between 0.15-0.22%, preferably 0.17 and 0.2% by mass. In this area, the above Effects of carbon are used particularly well, or its negative influences are limited.

According to the invention, silicon is present in an amount of 0.3-1.0% by mass, preferably 0.3-0.9% by mass. The addition of silicon in this area increases the strength of the alloy according to the invention by solid solution strengthening. In addition, an increase in the hardenability of the material and thus an increase in strength is also achieved with silicon. However, the effect of silicon is weaker than that of chromium or manganese. Therefore, according to the invention, at least 0.3% by mass of silicon is contained in the alloy. If the silicon content is too low, the required strength of the perforation gun barrel will not be achieved. If the silicon content is too high, there will be increased segregation and the associated risk of cracks during hardening or cold processing. The silicon content in the alloy according to the invention is therefore at most 1.0% by mass. In one embodiment, the silicon content of the alloy is between 0.4 and 0.85% by mass, preferably between 0.5 and 0.7% by mass. In these areas, the above-mentioned effects of silicon can be used particularly well, or its negative influences can be limited.

According to the invention, manganese is contained in the alloy in an amount of 1.0-4% by mass, preferably 1.2-3.5% by mass. The addition of manganese increases the hardenability of the material and increases the strength. The addition of manganese in the specified amount also achieves air-hardening properties of the material. Furthermore, manganese contributes to increasing the strength through mixed crystal strengthening, which is also referred to as solid solution strengthening. In one embodiment, the manganese content of the alloy is between 1.4 and 3.0% by mass, preferably between 1.6 and 2.5% by mass, in particular between 2.0 and 2.3% by mass. In these areas, the above-mentioned effects of manganese can be used particularly well.

According to the invention, chromium is present in an amount ranging from 0.5 to 2% by mass. On the one hand, this increases the through-hardenability of the material and increases the strength. On the other hand, air-hardening properties are achieved by adding the specified quantity of chromium. According to the invention, the amount of chromium is limited to a maximum of 2% by mass. A higher chromium content can lead to the precipitation of chromium carbides and thus to a deterioration in the weld union. In one embodiment, the chromium content of the alloy is between 0.5 and 1.5% by mass, for example between 1.0 and 1.8% by mass and in particular from 1.3 to 1.5% by mass. In this area, the above-mentioned effects of chromium can be used particularly well, or its negative influences can be limited.

According to the invention, molybdenum is contained in the alloy in an amount of 0.1 to 1% by mass. By adding molybdenum, the hardenability of the material can be further increased and the strength can be increased. In addition, molybdenum, like vanadium, can improve tempering resistance. Finally, molybdenum reduces the tendency to embrittlement under thermal stress, which is also referred to as tempering embrittlement. In particular, 500°C embrittlement can be avoided. In one embodiment, the molybdenum content of the alloy is between 0.1 and 0.7% by mass, for example between 0.14 and 0.7% by mass, in particular between 0.17 and 0.3% by mass. In this area, the above-mentioned effects of molybdenum can be used particularly well, or its negative influences can be limited.

According to the invention, vanadium is present in amounts of at least 0.05 to 0.2% by mass. Adding vanadium in these amounts can increase tempering resistance. In addition, a deterioration in the mechanical parameters, in particular the strength and deformation parameters, after thermal Stress reduced by formation of vanadium carbonitrides. In addition, the air-hardenability of the alloy is supported by the targeted addition of vanadium. In one embodiment, the vanadium content of the alloy is between 0.05 and 0.15% by mass, preferably between 0.06 and 0.15% by mass. In this area, the above-mentioned effects of vanadium can be used particularly well, or its negative influences can be limited.

Titanium is contained in an amount ranging from 0.02 - 0.1% by mass. By adding titanium, any nitrogen present in the alloy, which can be present in the alloy, for example, if vacuum degassing is omitted, can be bound. The formation of boron nitrides is thus prevented and the effect of boron, in particular the hardenability-increasing effect, can be utilized. If the alloy contains less than 0.02% by mass of titanium or no titanium is present, boron nitrides would form and the hardenability-increasing effect of boron could no longer be used. In one embodiment, the titanium content of the alloy is between 0.03 and 0.1% by mass, preferably between 0.04 and 0.08% by mass. In this area, the above-mentioned effects of titanium can be used particularly well, or its negative influences can be limited.

According to the invention, boron is contained in the alloy in a range of 0.001-0.01% by mass. This further increases the through-hardenability of the material. In one embodiment, the boron content of the alloy is between 0.001 and 0.006% by mass, preferably between 0.0015 and 0.0025% by mass. In this area, the above-mentioned effects of boron can be used particularly well,

A temper-resistant material is thus created with the alloy according to the invention, which also ensures that the material is hardened, has increased strength and can nevertheless be welded. In addition, the material has increased through-hardenability, which further increases its strength elevated. Furthermore, the alloy according to the invention also has air-hardening properties and the tendency to embrittlement is reduced. Finally, the alloy according to the invention has a high temperature resistance. In addition, due to the low contents of chromium, vanadium and molybdenum in the alloy according to the invention, the costs are reduced.

According to one embodiment, the steel alloy, expressed as a percentage by mass, consists of: C 0.17 - 0.20% si 0.5 - 0.7% Mn 1.7 - 2.2% Cr 0.6-1.4% Mon 0.1-0.2% V 0.05 - 0.10% Ti 0.03 - 0.08% B 0.0010 - 0.0030%

The remainder is iron and impurities caused by the smelting process. A tube according to the invention made from this steel alloy has a yield strength Re of at least 800 MPa--in the straightened state even more than 850 MPa--and a tensile strength Rm of at least 1150 MPa and a yield strength ratio R _e /R _m of less than 0.80.

According to one embodiment, the steel alloy consists of, expressed as a percentage by mass: C 0.18% si 0.6% Mn 2.1% Cr 0.6-1.4% Mon 0.1-0.2% V 0.07% Ti 0.05% B 0.0020% The remainder is iron and impurities caused by the smelting process.

The following steel alloys have proven to be particularly suitable:
Alloy 1: C 0.18% si 0.6% Mn 2.1% Cr 1.4% Mon 0.2% V 0.07% Ti 0.05% B 0.0020% The remainder is iron and impurities caused by the smelting process.
Alloy 2: C 0.18% si 0.6% Mn 2.1% Cr 0.6% Mon 0.2% V 0.07% Ti 0.05% B 0.0020% The remainder is iron and impurities caused by the smelting process.
Alloy 3: C 0.18% si 0.6% Mn 2.1% Cr 0.6% Mon 0.1% V 0.07% Ti 0.05% B 0.0020% The remainder is iron and impurities caused by the smelting process.

In addition to the specified alloying elements, the alloy used according to the invention can have at least one of the following alloying elements in the ranges specified in percent by mass: Al 0.03 - 0.05% no max 0.2% Cu max 0.22% sn 0.02% or less P max 0.015% S 0.003% or less N max 0.014%.

According to a further aspect, the invention relates to a perforation gun, which is characterized in that it comprises a perforation gun barrel according to the invention. Preferably, the perforating gun barrel is the outer tube of the perforating gun barrel.

Advantages and features that are explained with regard to the perforation gun barrel according to the invention also apply—insofar as applicable—to the perforation gun and vice versa and are only explained once if necessary.

• Figur 1: eine schematische Darstellung einer Perforationspistole mit einem Perforationspistolenrohr.

The present invention will now be explained again with reference to the accompanying drawings. Show it:

• figure 1 : a schematic representation of a perforating gun with a perforating gun barrel.

In figure 1 an embodiment of the perforation gun 1 is shown schematically. The perforation gun 1 includes a perforation gun tube 10, which can also be referred to as a hollow carrier. The perforation gun barrel 10 is preferably a seamless tubular element. Locally limited areas 100 with a reduced wall thickness are introduced into the perforation gun barrel 10 . The locally limited areas 100 each have a circular area. The areas 100 are distributed along the length of the perforating gun barrel 10 . An ignition unit 11 with ignition charges is introduced into the perforation gun barrel 10 . The explosive material of the ignition charge is ignited by the ignition unit 11 and as a result, on the one hand, the areas 100 of the perforation gun barrel 10 are opened and, on the other hand, the surrounding material, for example rock, is perforated.

reference list

1

perforating gun

10

perforating gun barrel

100

Area of lower wall thickness

11

ignition unit

Claims (19)

Perforating gun tube, characterized in that the tube consists of a steel alloy which, in addition to iron, includes the following alloying elements, specified in percent by mass: C 0.12 - 0.22% si 0.3 - 1.0% Mn 1.0 - 4% Cr 0.5 - 2% Mon 0.1 - 1%, V 0.05-0.2% Ti 0.02 - 0.1% and B 0.001 - 0.01% and smelting-related impurities, and
that the tube has _a yield strength, R _P0.2 , in the range of 750 to 1100 MPa. The perforating gun barrel of claim 1, wherein the barrel has an air-hardened bainitic structure. A perforating gun barrel according to claim 1 or 2, wherein the barrel has a yield strength, R _P0.2 , in the range of 850 to 1050 MPa _. Perforating gun tube according to one of claims 1 to 3, wherein the tube has a tensile strength R _m of at least 1100 MPa, preferably up to a maximum of 1400 MPa. Perforating gun barrel according to any one of claims 1 to 4, wherein the barrel has a yield strength ratio R _e /R _m of less than 0.9, preferably less than 0.87, more preferably 0.8 or 0.7. Perforating gun tube according to one of claims 1 to 5, wherein the tube has an elongation at break of more than 10%, preferably more than 13%, in particular more than 16%. A perforating gun barrel as claimed in any one of claims 1 to 6, wherein the barrel has been subjected to at least one straightening step after manufacture. A perforating gun barrel according to any one of claims 1 to 7, wherein the barrel has at least one predetermined breaking point in the form of a reduced wall thickness. Perforating gun barrel according to one of claims 1 to 8, wherein the carbon content is in the range of 0.15 - 0.22%, in particular 0.17 - 0.20%. Perforating gun barrel according to any one of claims 1 to 9, wherein the silicon content is in the range of 0.4 to 0.85%, preferably in the range of 0.5 to 0.7%. Perforating gun barrel according to any one of claims 1 to 10, wherein the manganese content is in the range of 1.4 to 3.0%, preferably in the range of 1.6 to 2.5%, in particular between 2.0 to 2.3%. Perforating gun barrel according to any one of claims 1 to 11, wherein the chromium content is in the range of 0.5 - 1.8%, preferably in the range of 1.0 to 1.8%, in particular 1.3 to 1.5%. Perforating gun barrel according to any one of claims 1 to 12, wherein the molybdenum content is in the range 0.14 - 0.7%, preferably in the range 0.17 - 0.3%. Perforating gun barrel according to any one of claims 1 to 13, wherein the vanadium content is in the range 0.05 - 0.15%, preferably in the range 0.06 - 0.15%. Perforating gun barrel according to any one of claims 1 to 14, wherein the titanium content is in the range of 0.03 - 0.1%, preferably in the range of 0.04 - 0.08%. A perforating gun barrel according to any one of claims 1 to 15, wherein the boron content is in the range 0.001-0.006%, preferably in the range 0.0015-0.0025%. Perforating pistol barrel according to one of Claims 1 to 16, characterized in that the steel alloy consists of, given in percentage by mass: C 0.17 - 0.20% Mn 1.7 - 2.2% si 0.5 - 0.7% Cr 0.6-1.4% V 0.05 - 0.10% B 0.0010 - 0.0030% Ti 0.03 - 0.08% Mon 0.1-0.2% The remainder is iron and impurities caused by the smelting process. A perforating gun, characterized in that it comprises a perforating gun barrel according to any one of claims 1 to 17. The perforating gun of claim 18 wherein the perforating gun barrel is the outer barrel of the perforating gun barrel.

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