WO2014114200A1

WO2014114200A1 - High-steel-grade anti-sulfur drill pipe material and preparation method thereof

Info

Publication number: WO2014114200A1
Application number: PCT/CN2014/070669
Authority: WO
Inventors: 韩礼红; 李方坡; 路彩虹; 王航; 李金凤; 冯耀荣; 刘永刚
Original assignee: 中国石油天然气集团公司; 中国石油天然气集团公司管材研究所
Priority date: 2013-01-22
Filing date: 2014-01-15
Publication date: 2014-07-31
Also published as: CN103060713B; CN103060713A

Abstract

The present invention provides a high-steel-grade anti-sulfur drill pipe material and a preparation method thereof. The high-steel-grade anti-sulfur drill pipe material comprises the following components (wt%): 0.15-0.25% of C, 0.20-0.50% of Mn, 0.20-0.30% of Si, 0.50-1.20% of Cr, 0.80-1.5% of Ni, 0.50-1.20% of Mo, 0.01-0.03% of Nb, 0.01-0.03% of V, 0.01-0.03% of Ti, 1.0-3.0% of Al, 0.005-0.01% of La, S with the weight being less than or equal to 0.001%, P with the weight being less than or equal to 0.003%, and the rest being Fe. The preparation method of the high-steel-grade anti-sulfur drill pipe material comprises the following steps: selecting raw materials according to the components; smelting, refining and continuously casting the raw materials to obtain a cast ingot; rolling the cast ingot to obtain a tubular product; and performing heat treatment on the tubular product to obtain the high-steel-grade anti-sulfur drill pipe material. The strength of the high-steel-grade anti-sulfur drill pipe material in the present invention can reach the steel grade range of 105-135 ksi.

Description

High steel grade sulfur-resistant drill pipe material and preparation method thereof

The invention relates to a high steel grade sulfur-resistant drill pipe material and a preparation method thereof, and belongs to the technical field of low carbon alloy steel metal materials. Background technique

The highest grade of sulfur-resistant drill pipe at home and abroad is 105ksi, and the foreign Japan NKK, France Mannesmann, Grant Company, and domestic Baosteel, Bohai Nengke and other companies have 105ksi steel grade sulfur-resistant drill pipe. However, the major oil and gas fields in western China, such as Sichuan, Chongqing and Tarim, generally have a depth of more than 5,000 meters and contain different degrees of hydrogen sulfide medium. For these deep wells over 5,000 meters, the 105ksi steel grade cannot meet the drilling load requirements. Moreover, the high-grade steel drill pipe is very sensitive to the stress corrosion cracking of hydrogen sulfide. The existence of hydrogen sulfide easily causes the hydrogen sulfide stress corrosion cracking of the high steel grade drill pipe, causing the drilling tool to break and fall out of the well, causing the drilling project. Great harm. Whether the high-grade drill pipe will cause hydrogen sulfide stress corrosion cracking mainly depends on the microstructure characteristics of the drill pipe, and the composition design and manufacturing process of the steel drill pipe material have obvious influence on the microstructure characteristics of the drill pipe, and the latter also decides The macro performance characteristics of the drill pipe.

Therefore, it is still necessary to develop a high-grade sulfur-resistant drill pipe material, through reasonable composition and process design, to optimize the microstructure of the material to achieve hydrogen sulfide stress corrosion cracking. Summary of the invention

In order to solve the above technical problems, an object of the present invention is to provide a high steel grade sulfur-resistant drill pipe material and a method of preparing the same. The high-grade sulfur-resistant drill pipe material of the invention can reach the steel-grade range of 105-135 ksi, and can be applied to deep well drilling engineering of oil and gas fields containing hydrogen sulfide, and meets the needs of safe drilling of deep wells of 5000-8000 meters of hydrogen sulfide-containing oil and gas fields.

To achieve the above object, the present invention provides a high-grade sulfur-resistant drill pipe material comprising, by mass percentage, a composition comprising the following composition: C: 0.15%-0.25%, Mn _: 0.20%-0.50%, Si: 0.20% -0.30%, Cr: 0.50% - 1.20%, Ni: 0.80% - 1.5%, Mo: 0.50% - 1.20%, b: 0.01% - 0.03%, V: 0.01% - 0.03%, Ti: 0.01% - 0.03 %, Ah 1.0%-3.0%, La: 0.005%-0.01%, S: <0.001%, P: <0.003%, and the balance is Fe.

In the composition of the above-mentioned high-grade sulfur-resistant drill pipe material, the carbon (C) content has a direct influence on the type and amount of carbides formed after heat treatment. Manganese (Mn) and silicon (Si) have significant effects on the fluidity of molten steel in material smelting. Chromium (Cr) and molybdenum (Mo) are carbide-forming elements, which are directly related to the reasonable combination of carbon and the second-phase dispersion characteristics and hardenability of the material after heat treatment. Nickel (Ni) is dissolved in the matrix, It is of great significance to improve the toughness level of steel, but if it is too much, it will form a free element of nickel, which has a negative effect on the stress corrosion of hydrogen sulfide, and the above content is most suitable.铌(b), vanadium (V), and titanium (Ti) are trace elements. Appropriate addition can inhibit the abnormal growth of crystal grains during hot rolling during the preparation of the material, and can refine grains and increase grain boundary strength. And stability, but the excessive addition of any element will lead to the coarsening of the dispersion and increase the sensitivity of the material to the stress corrosion cracking of hydrogen sulfide. The addition of aluminum (A1) can improve the oxidation resistance. The surface of the material can spontaneously form a dense A1 ₂ 0 ₃ film, preventing the hydrogen sulfide molecules and active hydrogen atoms from penetrating into the matrix, thereby improving the corrosion resistance of the material. It causes auto-oxidation in molten steel smelting to form inclusions and increase the sensitivity of the material to hydrogen sulfide stress corrosion cracking. The rare earth element lanthanum (La) can purify the inclusions in the material, reduce the phase boundary and residual stress of the grain boundary, improve the nucleation uniformity of the second phase particles, and ensure that the phase boundary and the grain boundary do not stress under the hydrogen sulfide environment. Corrosion cracking. Sulfur (S) and phosphorus (P) are impurity elements in steel and need to be strictly controlled to achieve the purity of the material.

In the present invention, preferably, the high-grade sulfur-resistant drill pipe material has the following mechanical properties: room temperature yield strength is 724-932 MPa, room temperature tensile strength is 850-1050 MPa, elongation is 25-35%, The room temperature impact toughness is 145-180J, the grain size is 9.0-12.0, and the hardness is HRC18-HRC25.

According to a specific embodiment of the present invention, preferably, the high-grade sulfur-resistant drill pipe material satisfies the performance requirement of the A method test in the NACE 0177 standard, that is, in the A solution, the high-grade sulfur-resistant drill pipe The material exerts a nominal yield strength of 85%, which does not break for 720 hours. Among them, the A solution is a saturated H ₂ S aqueous solution containing 5 wt% NaCl and 0.5 wt% CH ₃ COOH.

According to a specific embodiment of the present invention, preferably, the high-grade sulfur-resistant drill pipe material comprises cementite and alloying element carbide particles in an area of 5 square micrometers on average, as observed under a transmission electron microscope. -15, the aspect ratio of the particles is 1-1.5, and the ratio of the particle spacing on the grain boundary to the particle spacing in the grain is 0.8-1. The material has the characteristics of equiaxed grains and equiaxed and dispersed distribution of the second phase particles, which can realize the homogenization characteristics of the microstructure of the drill pipe material and reduce the micro stress concentration effect of the material.

The invention also provides a preparation method of the above-mentioned high-grade sulfur-resistant drill pipe material, which comprises the following steps: selecting raw materials according to the composition of the high-grade sulfur-resistant drill pipe material, and smelting and refining the raw materials; After continuous casting, an ingot is obtained; the ingot is rolled to obtain a pipe; and then the pipe is heat-treated to obtain the high-grade sulfur-resistant drill pipe material.

In the above preparation method, preferably, the step of heat treatment comprises three stages of normalizing treatment, quenching and tempering treatment, and spheroidizing treatment.

In the above preparation method, preferably, the normalizing treatment comprises: maintaining the pipe at 900-930 ° C The temperature was 30-60 minutes, then air cooled to room temperature to obtain a tube after normalizing.

In the above preparation method, preferably, the quenching and tempering treatment comprises: maintaining the normalized pipe at 900-950 ° C for 45-60 minutes, then water quenching to room temperature, and then at 600-640 ° Heat (tempering) at C for 45-90 minutes, then cool to room temperature to obtain a tempered tube.

In the above preparation method, preferably, the spheroidizing treatment comprises: causing the tempered pipe to be in

The tempering at 680-720 ° C for 30-45 minutes, followed by water cooling to room temperature, to obtain the high steel grade sulfur-resistant drill pipe material.

In the above heat treatment process, the normalizing treatment can eliminate the residual stress of the pipe and homogenize the microstructure. The quenching and tempering treatment can obtain a single and uniform tempered sorbite structure, control the austenitizing temperature and time, and ensure that the pipe is fully austenitized without grain coarsening. The spheroidizing treatment can spheroidize the second phase particles on the tempered sorbite structure, reduce the aspect ratio thereof, reduce the microscopic stress concentration around the second phase particles of the pipe, and reduce the hydrogen sulfide of the obtained drill pipe material. The sensitivity of stress corrosion cracking. The water cooling treatment in the tempering and spheroidizing stage can control the number and morphological characteristics of the second phase particles to prevent further growth and coarsening.

In the above preparation method, preferably, the steps of smelting, refining, and continuous casting include: adding an alloying element as a raw material in pure iron water, smelting the raw material through a converter, and then vacuum degassing, refining outside the furnace, and After the electroslag remelting treatment, it is cast into an ingot. Among them, converter smelting, vacuum degassing, re-refining and electroslag remelting are all conventional processes for smelting steel in the field, and specific operation steps thereof are well known to those skilled in the art. More preferably, the ingot is a cylindrical ingot having an outer diameter of Φ230 - Φ350. Can the material purification target be achieved by using the above process? , S technical requirements for lower impurity content.

In the above preparation method, preferably, the step of rolling comprises: holding the ingot at 950 ° C to 1150 ° C for 45-60 minutes to obtain a material having a full austenite structure, followed by The material having the full austenite structure was sequentially perforated and rolled at 900-1100 ° C to obtain a pipe. Among them, the temperature of the perforation and the rolling tube may be the same or different as long as it is in the range of 900-1100 °C. More preferably, the cross-sectional area of the pipe is 4-10% of the cross-sectional area of the ingot. The material treated in accordance with the above rolling process has a fine grain size to provide basic material properties for subsequent heat treatment.

In the above rolling process, the control of the rolling temperature can effectively utilize the free elemental characteristics of Cr, Mo, b, V, Ti alloy elements in a specific temperature range, increase the dynamic recrystallization heterogeneous nucleation, and realize the crystal Grain refinement and homogenization. The control of the holding time ensures that the ingot is fully austenitized, but no grain coarsening occurs. For the control of the cross-sectional area of the pipe, that is, for the control of the amount of rolling deformation, it is possible to make full use of the mechanical deformation to further refine the grain while improving the toughness of the material.

The high-grade sulfur-resistant drill pipe material provided by the invention can be prepared by conventional techniques such as tapping and drilling. 105-135ksi steel grade range of sulfur-resistant drill pipe products. The anti-sulfur drill pipe product can be applied to deep well drilling engineering of oil and gas fields containing hydrogen sulfide, and meets the needs of safe drilling of deep wells of 5000-8000 meters in hydrogen sulfide oil and gas fields such as Sichuan, Chongqing and Tarim. DRAWINGS

1 is a metallographic diagram of the high-grade sulfur-resistant drill pipe material of Example 1.

2 is a transmission electron micrograph of a second phase particle of the high-grade sulfur-resistant drill pipe material of Example 1. Figure 3 is a photograph of the high-grade sulfur-resistant drill pipe material of Examples 1-3 after being tested for resistance to hydrogen sulfide stress corrosion cracking. detailed description

The technical features of the present invention are described in detail below, but are not to be construed as limiting the scope of the invention.

Example 1-3

Embodiments 1-3 respectively provide a high-grade sulfur-resistant drill pipe material, and the preparation method thereof comprises the following steps: selecting raw materials according to the composition of the high-grade sulfur-resistant drill pipe material, wherein the height of the embodiment 1-3 is high. The composition of the steel grade sulfur-resistant drill pipe material is shown in Table 1;

An alloying element is added as raw material in pure iron water, and the raw material is smelted by a converter, and then subjected to vacuum degassing, refining outside the furnace, and electroslag remelting treatment, and then cast into an ingot, wherein, the obtained in Example 1-3 The outer diameter of the ingot is as shown

2;

Then, the ingot is kept at a certain temperature for a certain time to obtain a material having a full austenite structure, and then the material having the full austenite structure is sequentially perforated and rolled at a certain temperature to form The pipe material, wherein the pre-perforation heat-insulation process, the perforation temperature, the pipe temperature, and the cross-sectional area ratio of the ingot after rolling and the ingot before rolling are as shown in Table 2;

Subsequently, the pipe is subjected to heat treatment, the normal heat treatment including normalizing, quenching and tempering and spheroidizing to form the high-grade grade sulfur-resistant drill pipe material, wherein the normalizing, modulating and the heat treatment in the heat treatment process of Examples 1-3 The process parameters of spheroidization are shown in Table 3.

Table 1 Example 1-3 high steel grade sulfur-resistant drill pipe material composition, wt% Example C Si Mn P S Cr Ni

1 0.16 0.21 0.22 0.0026 0.00075 1.15 1.45

2 0.20 0.25 0.35 0.0024 0.00082 0.83 1.19

3 0.24 0.29 0.48 0.0019 0.00078 0.56 0.86 Example Mo V b Ti Al La Fe

1 1.16 0.012 0.026 0.013 1.15 0.0052

2 0.97 0.020 0.016 0.028 1.82 0.0075 balance

3 0.58 0.028 0.011 0.019 2.85 0.0096 Balance Table 2 Example 1-3 Ingot outer diameter and rolling process parameters

Table 3 Example 1-3 heat treatment process parameters

The high-grade sulfur-resistant drill pipe materials of Examples 1-3 were tested for room temperature yield strength, room temperature tensile strength, elongation, room temperature impact toughness, Rockwell hardness, and hydrogen sulfide stress corrosion cracking resistance test. Table 4 shows. The mechanical properties were measured according to the API Spec 5D drill pipe standard. It can be seen from Table 4 that the mechanical properties of the high-grade sulfur-resistant drill pipe materials of Examples 1-3 are in the range of 105-135 ksi steel grade, and the plasticity and toughness of the materials. good. The hydrogen sulfide stress corrosion cracking resistance test is carried out according to the NACE TM0177 standard A method. The specific steps are as follows: The high steel grade sulfur-resistant drill pipe material is placed in the A solution (a saturated H ₂ S aqueous solution containing 5 wt% NaCl and 0.5 wt% CH ₃ COOH). In the case of 85% of the nominal steel grade (ie yield strength) under constant load for 720 hours, if the high-grade grade sulfur-resistant drill pipe material does not break, it means that it passed the test and was evaluated as qualified. 3 is a photograph of the high-grade sulfur-resistant drill pipe material of Example 1-3 after being tested for resistance to hydrogen sulfide stress corrosion cracking, and the high steel of Example 1, Example 2, and Example 3 is sequentially from top to bottom. Grade anti-sulfur drill pipe material (the thread on the surface of the material in Figure 3 is the thread processed for the device clamping connection during the test). As can be seen from FIG. 3, the drill pipe materials of Examples 1-3 are all subjected to hydrogen sulfide stress corrosion cracking resistance. Table 4 Performance test results of high steel grade sulfur-resistant drill pipe materials of Examples 1-3

Figure 1 shows the metallographic structure of the high steel grade sulfur-resistant drill pipe material of Example 1. The morphology of the metallographic structure in Fig. 1 indicates that the grain size of the material is small, equiaxed, and the grain size is about 5 μm, which is in the range of 9-12; and the material structure is uniform and there is no banding segregation. Figure 2 shows the characteristics of the second phase particles of the high steel grade sulfur-resistant drill pipe material of Example 1 under a transmission electron microscope. Figure 2 shows that the second phase particles of the material are equiaxed, small in size, about 0.2 μm in diameter, free from particle aggregation, and have good dispersion distribution characteristics. Therefore, the high-grade sulfur-resistant drill pipe material of the first embodiment achieves the homogenization characteristics of the microstructure, reduces the microscopic stress concentration effect, and further reduces the sensitivity of the drill pipe material to hydrogen sulfide stress corrosion cracking.

Claims

claims

1. A high-grade sulfur-resistant drill pipe material, which consists of the following ingredients in terms of mass percentage: C: 0.15%-0.25%, Mn _: 0.20%-0.50%, Si: 0.20%-0.30%, Cr: 0.50%- 1.20%, Ni: 0.80%- 1.5%, Mo: 0.50%- 1.20%, b: 0.01%-0.03%, V: 0.01%-0.03%, Ti: 0.01%-0.03%, Ah 1.0%- 3.0%, La: 0.005%-0.01%, S: <0.001%, P: <0.003%, the balance is Fe.

2. The high-grade sulfur-resistant drill pipe material as claimed in claim 1, which has the following mechanical performance indicators: room temperature yield strength is 724-932MPa, room temperature tensile strength is 850-1050MPa, elongation is 25-35%, The room temperature impact toughness is 145-180J, the grain size is 9.0-12.0, and the hardness is HRC18-HRC25.

3. The high-grade sulfur-resistant drill pipe material according to claim 1, which meets the performance requirements of the A method test in the NACE 0177 standard, that is, in the A solution, the high-grade sulfur-resistant drill pipe material is subjected to 85 % nominal yield strength, which can sustain load for 720 hours without breaking.

4. The high-grade sulfur-resistant drill pipe material according to claim 1, when observed under a transmission electron microscope, the high-grade sulfur-resistant drill pipe material contains cementite and alloying elements in an average area of 100 square microns. The number of carbide particles is 5-15, the aspect ratio of the particles is 1-1.5, and the ratio of the particle spacing on the grain boundary to the particle spacing within the grain is 0.8-1.

5. The method for preparing the high-grade sulfur-resistant drill pipe material according to any one of claims 1 to 4, which includes the following steps: selecting raw materials according to the composition of the high-grade sulfur-resistant drill pipe material, and After the raw materials are smelted, refined and continuously cast, an ingot is obtained; the ingot is rolled to obtain a pipe; and the pipe is then heat treated to obtain the high-grade sulfur-resistant drill pipe material.

6. The preparation method according to claim 5, wherein the heat treatment step includes three stages of normalizing treatment, quenching and tempering treatment and spheroidizing treatment in sequence.

7. The preparation method according to claim 6, wherein the normalizing treatment includes: insulating the pipe at 900-930°C for 30-60 minutes, and then air-cooling to room temperature to obtain the normalized pipe.

8. The preparation method according to claim 6 or 7, wherein the quenching and tempering treatment includes: insulating the normalized pipe at 900-950°C for 45-60 minutes, then quenching with water to room temperature, and then Keep it at 600-640°C for 45-90 minutes, and then water-cool to room temperature to obtain a quenched and tempered pipe.

9. The preparation method according to any one of claims 6 to 8, wherein the spheroidization treatment includes: insulating the tempered pipe at 680-720°C for 30-45 minutes, and then water-cooling to room temperature, The high-grade sulfur-resistant drill pipe material is obtained.

10. The preparation method according to claim 5, wherein the steps of smelting, refining and continuous casting include: adding alloying elements as raw materials to pure molten iron, smelting the raw materials through a converter, and then vacuum degassing, After refining outside the furnace and electroslag remelting, it is cast into ingots.

11. The preparation method according to claim 10, wherein the ingot is a cylindrical ingot with an outer diameter of Φ230-Φ350.

12. The preparation method according to claim 5, wherein the rolling step includes: keeping the ingot at 950°C-1150°C for 45-60 minutes to obtain a fully austenite structure. The material is then pierced and rolled at 900-1100° C. to obtain a pipe.

13. The preparation method according to claim 12, wherein the cross-sectional area of the pipe is 4-10% of the cross-sectional area of the ingot.