High-temperature-resistant soluble alloy material and preparation method thereof

Abstract

The invention discloses a high-temperature-resistant soluble alloy material, which belongs to the technical field of underground key tools for petroleum and natural gas drilling and fracturing and comprises the following components in percentage by mass: 10 to 14 weight percent of Gd, 4 to 6 weight percent of Y, 0.5 to 1 weight percent of Zn, 0.6 to 1 weight percent of Ca, 2 to 4 weight percent of Ga and the balance of Mg. The invention further discloses a preparation method of the high-temperature-resistant soluble alloy material. The prepared high-temperature-resistant soluble alloy material is reasonable in component proportion, simple in production process, high in safety and reliability and low in cost, the performance of the high-temperature-resistant soluble alloy material meets the performance requirement of a fracturing tool material in a staged fracturing technology, and application of magnesium alloy in the field of petroleum and natural gas exploitation with extremely harsh conditions is expanded.

Description

Technical Field

[0001] The invention relates to the technical field of downhole key tools for oil and natural gas drilling and fracturing, and in particular to a high-temperature resistant soluble alloy material and a preparation method thereof. Background Art

[0002] With the in-depth development of domestic oil fields, the number of deep wells and ultra-deep wells in low-permeability reservoirs is increasing. The development of deep oil and gas resources faces the characteristics of deep wells, high temperature, high pressure, high stress, high carbon dioxide, etc. The oil production conditions are getting worse day by day. The research and development of deep well downhole tools is becoming more and more the key to oil production projects. As the difficulty of oil and gas extraction continues to increase, the development of unconventional oil and gas reservoirs has become the main battlefield.

[0003] The multi-layer, multi-stage, staged fracturing technology in hydraulic fracturing is currently the most efficient technology for exploiting low-permeability unconventional oil and gas resources. At present, most of the downhole tools used in this technology are made of materials such as carbon steel, stainless steel and ductile iron. There are problems such as long drilling and grinding time, difficulty in drilling and milling, and difficulty in discharging drilling and grinding products during the recovery or removal process. If soluble materials are introduced to replace some downhole tools, the soluble materials can be dissolved in situ in the downhole environment after fracturing is completed, thereby eliminating the processes such as drilling and grinding and flowback, which will greatly reduce production costs and improve oil and gas extraction efficiency. The research on the application of existing soluble metals in fracturing downhole tools needs to be strengthened, and the research and development of soluble materials still needs to be further strengthened, especially soluble materials that are resistant to high temperatures, have good mechanical properties, and have controllable solubility properties are urgently needed to be developed. Summary of the invention

[0004] The purpose of the present invention is to provide a high-temperature resistant soluble alloy material and a preparation method thereof, so as to solve the technical problems in the prior art that soluble metals have poor high-temperature resistance and mechanical properties.

[0005] To achieve the above object, an embodiment of the present invention provides a high temperature resistant soluble alloy material, comprising the following components in proportion by mass percentage:

[0006] Gd: 10wt%-14wt%, Y: 4wt%-6wt%, Zn: 0.5wt%-1wt%;

[0007] Ca: 0.6wt%-1wt%, Ga: 2wt%-4wt, and the balance is Mg.

[0008] Furthermore, the high temperature resistant soluble alloy material includes the following components in proportion by mass percentage:

[0009] Gd: 12wt%-14wt%, Y: 4wt%-5wt%, Zn: 0.5wt%-0.75wt%;

[0010] Ca: 0.8wt%-1wt%, Ga: 3wt%-4wt, and the balance is Mg.

[0011] Based on a high temperature resistant soluble alloy material disclosed in the present invention, the present invention also discloses a method for preparing the high temperature resistant soluble alloy material, comprising the following steps:

[0012] Mg is preheated and then melted;

[0013] The preheated Gd, Y, Ca, Zn and Ga are sequentially added to the molten Mg to continue smelting;

[0014] Adding a refining agent to the smelted raw material for refining;

[0015] The refined material is scraped, left to stand, and poured into a mold after removing the scum to obtain a high-temperature resistant soluble alloy ingot;

[0016] The high temperature resistant soluble alloy ingot is subjected to hot extrusion and aging treatment to obtain the high temperature resistant soluble alloy material.

[0017] Furthermore, the preheating temperature is 150° C.-200° C., and the preheating time is 1.5 h-2.5 h.

[0018] Furthermore, the Mg is melted, including: passing a protective gas through the Mg and then heating it to increase the temperature.

[0019] Furthermore, Gd, Y and Ca are added in the form of a master alloy, Ga and Zn are added in the form of pure metal elements, and Mg is added in the form of a master alloy and a pure metal element.

[0020] Furthermore, Gd is added in the form of Mg-Gd alloy, Y is added in the form of Mg-Y alloy, and Ca is added in the form of Mg-Ca alloy.

[0021] Further, the preheated Gd, Y, Ca, Zn and Ga are sequentially added to the molten Mg for further smelting, including: Gd, Y, Ca, Zn and Ga are sequentially added to the molten Mg, and the smelting temperature is increased, the smelting temperature is kept once, the smelting temperature is stirred, and the smelting temperature is kept twice.

[0022] Furthermore, the refined material is scraped, allowed to stand, and the scum is skimmed before being poured into a mold to obtain a high-temperature resistant soluble alloy ingot, including a scum skimming temperature of 700°C-730°C.

[0023] Furthermore, the temperature of hot extrusion is 450°C-480°C, and the extrusion ratio is 4-16; the temperature of aging treatment is 200°C-250°C, and the time is 9h-11h.

[0024] In summary, the beneficial effects of the present invention are:

[0025] 1. The high-temperature resistant soluble alloy material of the present invention has a high-strength soluble alloy that meets the requirements of fracturing tools through the synergistic effect of appropriate amounts of various components and preparation methods. The high-temperature resistant performance is far superior to similar products. It is based on Mg alloy, and by adding a certain proportion of Gd, Y, Zn, Ca, and Ga elements, adjusting the mass fraction ratio of each element in the alloy, and preparing a product with a yield strength of more than 350MPa at 175°C through a melting-hot extrusion process, which is more than 120MPa higher than the existing soluble temperature-resistant magnesium alloy, and the dissolution rate in 98°C, 1% KCl solution is equivalent to or exceeds the rate of the existing soluble magnesium alloy, but the production process is simple, the safety and reliability are high, and the existing alloy equipment can be used for industrial production. It is a relatively low-cost high-temperature resistant and soluble alloy product that meets the requirements of fracturing tools.

[0026] 2. The Gd and Y elements in the high-temperature resistant soluble alloy material of the present invention are rare earth elements, which can improve the mechanical properties of the alloy. The three elements Ca, Zn and Ga form an LPSO phase (long period ordered stacking structure), and the Zn element and the Mg element form a Mg2Zn phase to improve the hardness of the material. The Ga element is a low melting point element and can make the alloy dissolve in a Cl- solution environment.

[0027] 3. The high-temperature resistant soluble alloy material prepared by the present invention has a reasonable composition ratio, a simple production process, high safety and reliability, and low cost. Its performance meets the performance requirements of fracturing tool materials in staged fracturing technology, expanding the application of magnesium alloys in the field of oil and natural gas extraction under extremely harsh conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a schematic flow chart of the method for preparing the high temperature resistant soluble alloy material of the present invention;

[0029] Figure 2 This is a metallographic morphology diagram of the extruded alloy in Example 2 of the present invention;

[0030] Figure 3 This is a metallographic morphology diagram of the aged alloy in Example 2 of the present invention;

[0031] Figure 4 This is a SEM image of the aged alloy in Example 2 of the present invention;

[0032] Figure 5 This is an appearance diagram of the high temperature resistant soluble alloy material in Example 1 of the present invention dissolved in a 98° C., 1% KCl solution for 3 hours. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical solution and advantages of the embodiments of the present disclosure clearer, the technical solution in the embodiments of the present disclosure will be clearly and completely described below in conjunction with the drawings in the embodiments of the present disclosure. Obviously, the described embodiments are part of the embodiments of the present disclosure, not all of the embodiments. Based on the embodiments in the present disclosure, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present disclosure.

[0034] The present invention provides a high temperature resistant soluble alloy material, comprising the following components in mass percentage: Gd: 10wt%-14wt%, Y: 4wt%-6wt%, Zn: 0.5wt%-1wt%, Ca: 0.6wt%-1wt%, Ga: 2wt%-4wt%, and the balance is Mg;

[0035] Furthermore, the high temperature resistant soluble alloy material includes the following components in proportion by mass percentage: Gd: 12wt%-14wt%, Y: 4wt%-5wt%, Zn: 0.5wt%-0.75wt%, Ca: 0.8wt%-1wt%, Ga: 3wt%-4wt%, and the balance is Mg.

[0036] A method for preparing a high temperature soluble alloy material, such as Figure 1 As shown, the following steps are included:

[0037] Step (1): Mg is preheated and then melted; specifically, before smelting, the prepared raw materials (all metal raw materials involved), molds and experimental tools are placed in a baking oven for preheating at a temperature of 150°C-200°C for 1.5h-2.5h. After the preheating is completed, the temperature of the resistance furnace is set to 500°C, and the crucible is placed in the resistance furnace. When the crucible is heated to 500°C, the preheated pure magnesium is added, and a protective gas is passed, and then the temperature is raised to 700°C.

[0038] Step (2): adding the preheated Gd, Y, Ca, Zn and Ga to the melted Mg in sequence and continuing smelting; after the Mg in step (1) is completely melted, adding the preheated Mg-Gd, Mg-Y, Mg-Ca master alloy, pure Zn and pure Ga into the melt in sequence, and raising the smelting temperature to 740°C-760°C, keeping the temperature for 20min-30min, stirring for 2min, and then keeping the temperature for 30min;

[0039] Step (3): adding a refining agent to the smelted raw material for refining; specifically: after the heat preservation in step (3) is completed, the refining agent is added and allowed to stand for 5 minutes for refining, the refining agent is used for fine purification and degassing, and the main components include elements such as calcium, strontium, aluminum, and manganese;

[0040] Step (4): the refined material is scraped, allowed to stand, and the scum is removed before pouring into a mold to obtain a high-temperature resistant soluble alloy ingot; specifically, the refined material in step (4) is scraped, allowed to stand for 10 minutes, and after the standing is completed, the temperature is set to 700°C-730°C, and when the melt temperature reaches 700°C-730°C, the scum is removed, and the melt is poured into a preheated mold to obtain a high-temperature resistant soluble alloy ingot;

[0041] Step (5): hot extruding and aging the high-temperature resistant soluble alloy ingot to obtain a high-temperature resistant soluble alloy material; specifically: hot extruding the ingot, the extrusion temperature is 450°C-480°C, the extrusion ratio is 4-16, and after extrusion, aging treatment is performed to obtain the desired soluble alloy material, wherein the aging treatment temperature is 200°C-250°C, and the time is 9h-11h.

[0042] Example 1

[0043] A high temperature resistant soluble alloy material comprises the following components in proportion by mass percentage: 10wt% Gd, 4wt% Y, 0.5wt% Zn, 0.6wt% Ca, 2wt% Ga, and the balance being Mg, the sum of the mass percentages of the components being 100%.

[0044] A method for preparing a high temperature resistant soluble alloy material comprises the following steps:

[0045] Step (1): Before smelting, the prepared raw materials, molds and experimental tools are placed in a baking oven for preheating at 180°C for 2 hours;

[0046] Step (2): setting the temperature of the resistance furnace to 500° C. and placing the crucible in the resistance furnace. When the crucible is heated to 500° C., pure magnesium is added, and protective gas is passed through, and then the temperature is raised to 700° C.;

[0047] Step (3): After magnesium is completely melted, Mg-Gd, Mg-Y, Mg-Ca master alloy, pure Zn, and pure Ga are sequentially placed into the melt, and the melting temperature is raised to 740°C-760°C. After keeping the temperature for 25 minutes, stir for 2 minutes, and then keep the temperature for 30 minutes.

[0048] Step (4): after heat preservation, add refining agent and let it stand for 5 minutes for refining, then scrape the residue and let it stand for another 10 minutes;

[0049] Step (5): After standing, the temperature is set to 710°C, and when the melt temperature reaches 710°C, the scum is skimmed off;

[0050] Step (6): pouring the melt into a preheated mold to obtain a high temperature resistant soluble alloy ingot;

[0051] Step (7): hot-extrude the ingot at an extrusion temperature of 450°C and an extrusion ratio of 16, and perform aging treatment (220°C / 10h) after extrusion to obtain the desired high-temperature resistant soluble alloy material.

[0052] Example 2

[0053] A high-temperature resistant soluble alloy material comprises the following components in proportion by mass percentage: 12wt% Gd, 5wt% Y, 0.75wt% Zn, 0.8wt% Ca, 3wt% Ga, and the remainder Mg, the sum of the mass percentages of the components being 100%.

[0054] A method for preparing a high temperature resistant soluble alloy material comprises the following steps:

[0055] Step (1): Before smelting, the prepared raw materials, molds and experimental tools are placed in a baking oven for preheating at 180°C for 2 hours;

[0056] Step (2): setting the temperature of the resistance furnace to 500° C. and placing the crucible in the resistance furnace. When the crucible is heated to 500° C., pure magnesium is added, and protective gas is passed through, and then the temperature is raised to 700° C.;

[0057] Step (3): After magnesium is completely melted, Mg-Gd, Mg-Y, Mg-Ca master alloy, pure Zn, and pure Ga are sequentially placed into the melt, and the melting temperature is raised to 740°C-760°C. After keeping the temperature for 25 minutes, stir for 2 minutes, and then keep the temperature for 30 minutes.

[0058] Step (4): after heat preservation, add refining agent and let it stand for 5 minutes for refining, then scrape the residue and let it stand for another 10 minutes;

[0059] Step (5): After standing, the temperature is set to 710°C, and when the melt temperature reaches 710°C, the scum is skimmed off;

[0060] Step (6): pouring the melt into a preheated mold to obtain a high temperature resistant soluble alloy ingot;

[0061] Step (7): hot-extrude the ingot at an extrusion temperature of 460°C and an extrusion ratio of 12, and perform aging treatment (220°C / 10h) after extrusion to obtain the desired high-temperature resistant soluble alloy material.

[0062] Example 3

[0063] A high temperature resistant soluble alloy material comprises the following components in proportion by mass percentage: Gd: 14wt%, Y: 6wt%, Zn: 1wt%, Ca: 1wt%, Ga: 4wt%, and the balance is Mg, and the sum of the mass percentages of the components is 100%.

[0064] A method for preparing a high temperature resistant soluble alloy material comprises the following steps:

[0065] Step (1): Before smelting, the prepared raw materials, molds and experimental tools are placed in a baking oven for preheating at 180°C for 2 hours;

[0066] Step (2): setting the temperature of the resistance furnace to 500° C. and placing the crucible in the resistance furnace. When the crucible is heated to 500° C., pure magnesium is added, and protective gas is passed through, and then the temperature is raised to 700° C.;

[0067] Step (3): After magnesium is completely melted, Mg-Gd, Mg-Y, Mg-Ca master alloy, pure Zn, and pure Ga are sequentially placed into the melt, and the melting temperature is raised to 740°C-760°C. After keeping the temperature for 25 minutes, stir for 2 minutes, and then keep the temperature for 30 minutes.

[0068] Step (4): after heat preservation, add refining agent and let it stand for 5 minutes for refining, then scrape the residue and let it stand for another 10 minutes;

[0069] Step (5): After standing, the temperature is set to 710°C, and when the melt temperature reaches 710°C, the scum is skimmed off;

[0070] Step (6): pouring the melt into a preheated mold to obtain a high temperature resistant soluble alloy ingot;

[0071] Step (7): hot-extrude the ingot at an extrusion temperature of 480°C and an extrusion ratio of 8, and perform aging treatment (220°C / 10h) after extrusion to obtain the desired high-temperature resistant soluble alloy material.

[0072] Comparative Example 1

[0073] A high temperature resistant soluble alloy material comprises the following components in proportion by mass percentage: Gd: 14wt%, Y: 6wt%, Zn: 1wt%, Ca: 1wt%, and the balance is Mg, and the sum of the mass percentages of the components is 100%.

[0074] A method for preparing a high temperature resistant soluble alloy material comprises the following steps:

[0075] Step (1): Before smelting, the prepared raw materials, molds and experimental tools are placed in a baking oven for preheating at 180°C for 2 hours;

[0076] Step (2): setting the temperature of the resistance furnace to 500° C. and placing the crucible in the resistance furnace. When the crucible is heated to 500° C., pure magnesium is added, and protective gas is passed through, and then the temperature is raised to 700° C.;

[0077] Step (3): After magnesium is completely melted, Mg-Gd, Mg-Y, Mg-Ca master alloy and pure Zn are sequentially placed into the melt, and the melting temperature is raised to 740°C-760°C. After keeping the temperature for 25 minutes, the mixture is stirred for 2 minutes and then kept at the temperature for 30 minutes.

[0078] Step (4): after heat preservation, add refining agent and let it stand for 5 minutes for refining, then scrape the residue and let it stand for another 10 minutes;

[0079] Step (5): After standing, the temperature is set to 710°C, and when the melt temperature reaches 710°C, the scum is skimmed off;

[0080] Step (6): pouring the melt into a preheated mold to obtain a high temperature resistant soluble alloy ingot;

[0081] Step (7): hot-extrude the ingot at an extrusion temperature of 480°C and an extrusion ratio of 8, and perform aging treatment (220°C / 10h) after extrusion to obtain the desired high-temperature resistant soluble alloy material.

[0082] Comparative Example 2

[0083] A high-temperature resistant soluble alloy material comprises the following components in proportion by mass percentage: Gd: 14wt%, Y: 6wt%, Zn: 1wt%, Ca: 1wt%, Ga: 5wt%, and the balance is Mg, and the sum of the mass percentages of the components is 100%.

[0084] A method for preparing a high temperature resistant soluble alloy material comprises the following steps:

[0085] Step (1): Before smelting, the prepared raw materials, molds and experimental tools are placed in a baking oven for preheating at 180°C for 2 hours;

[0086] Step (2): setting the temperature of the resistance furnace to 500° C. and placing the crucible in the resistance furnace. When the crucible is heated to 500° C., pure magnesium is added, and protective gas is passed through, and then the temperature is raised to 700° C.;

[0087] Step (3): After magnesium is completely melted, Mg-Gd, Mg-Y, Mg-Ca master alloy, pure Zn, and pure Ga are sequentially placed into the melt, and the melting temperature is raised to 740°C-760°C. After keeping the temperature for 25 minutes, stir for 2 minutes, and then keep the temperature for 30 minutes.

[0088] Step (4): after heat preservation, add refining agent and let it stand for 5 minutes for refining, then scrape the residue and let it stand for another 10 minutes;

[0089] Step (5): After standing, the temperature is set to 710°C, and when the melt temperature reaches 710°C, the scum is skimmed off;

[0090] Step (6): pouring the melt into a preheated mold to obtain a high temperature resistant soluble alloy ingot;

[0091] Step (7): hot-extrude the ingot at an extrusion temperature of 480°C and an extrusion ratio of 8, and perform aging treatment (220°C / 10h) after extrusion to obtain the desired high-temperature resistant soluble alloy material.

[0092] The high temperature resistant soluble alloy materials prepared in Examples 1-3 and the alloy materials prepared in Comparative Examples 1-2 were tested for mechanical properties and solubility properties at 175°C. The test results are shown in Table 1.

[0093] Table 1: Mechanical properties and dissolution properties at 175℃

[0094]

[0095]

[0096] It can be seen from Table 1 that: compared with Example 2, the absence of Ga element in Comparative Example 1 causes the prepared alloy material to be insoluble; compared with Example 2, the Ga element content in Comparative Example 2 is too high, resulting in lower mechanical properties of the prepared alloy material.

[0097] In summary, the high temperature resistant soluble alloy materials prepared in Examples 1-3 of the present invention have excellent tensile strength, elongation after fracture and yield strength, and the dissolution rate in 1% KCl solution at 98° C. is also good.

[0098] The embodiments described above are merely descriptions of preferred implementations of the present invention and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary engineering and technical personnel in the field should all fall within the protection scope of the claims of the present invention.

Claims

1. A high temperature resistant soluble alloy material, characterized in that: It includes the following components in proportion by mass: Gd: 10wt%-14wt%, Y: 4wt%-6wt%, Zn: 0.5wt%-1wt%; Ca: 0.6wt%-1wt%, Ga: 2wt%-4wt, and the balance is Mg.

2. A high temperature resistant soluble alloy material as claimed in claim 1, characterized in that: The high temperature resistant soluble alloy material comprises the following components in proportion by mass percentage: Gd: 12wt%-14wt%, Y: 4wt%-5wt%, Zn: 0.5wt%-0.75wt%; Ca: 0.8wt%-1wt%, Ga: 3wt%-4wt, and the balance is Mg.

3. A method for preparing a high temperature resistant soluble alloy material according to any one of claims 1-2, characterized in that: The following steps are involved: Mg is preheated and then melted; The preheated Gd, Y, Ca, Zn and Ga are sequentially added to the molten Mg to continue smelting; Adding a refining agent to the smelted raw material for refining; The refined material is scraped, left to stand, and poured into a mold after removing the scum to obtain a high-temperature resistant soluble alloy ingot; The high temperature resistant soluble alloy ingot is subjected to hot extrusion and aging treatment to obtain a high temperature resistant soluble alloy material.

4. The method for preparing a high temperature resistant soluble alloy material according to claim 3, characterized in that: The preheating temperature is 150° C.-200° C., and the preheating time is 1.5 h-2.5 h.

5. The method for preparing a high temperature resistant soluble alloy material according to claim 3, characterized in that: The melting treatment of Mg comprises: passing a protective gas through Mg and then heating it to increase the temperature.

6. The method for preparing a high temperature resistant soluble alloy material according to claim 3, characterized in that: Gd, Y and Ca are added in the form of a master alloy, Ga and Zn are added in the form of pure metal elements, and Mg is added in the form of a master alloy and a pure metal element.

7. The method for preparing a high temperature resistant soluble alloy material according to claim 3, characterized in that: The Gd is added in the form of a Mg-Gd alloy, the Y is added in the form of a Mg-Y alloy, and the Ca is added in the form of a Mg-Ca alloy.

8. The method for preparing a high temperature resistant soluble alloy material according to claim 3, characterized in that: The method of sequentially adding the preheated Gd, Y, Ca, Zn and Ga into the molten Mg for further smelting comprises: sequentially adding Gd, Y, Ca, Zn and Ga into the molten Mg, sequentially increasing the smelting temperature, performing primary heat preservation, stirring and secondary heat preservation.

9. The method for preparing a high temperature resistant soluble alloy material according to claim 3, characterized in that: The refined material is scraped, left to stand, and the scum is skimmed before being poured into a mold to obtain a high-temperature resistant soluble alloy ingot, wherein the temperature for skimming the scum is 700°C-730°C.

10. The method for preparing a high temperature resistant soluble alloy material according to claim 3, characterized in that: The temperature of the hot extrusion is 450° C.-480° C., and the extrusion ratio is 4-16; the temperature of the aging treatment is 200° C.-250° C., and the time is 9h-11h.

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