A diamond-impregnated centralizer and its manufacturing method and application

Abstract

The present invention provides a diamond-impregnated centralizer, relating to the field of centralizers. The diamond-impregnated centralizer comprises: a centralizer rigid body and a plurality of wear-resistant strips. The plurality of wear-resistant strips are distributed in an annular shape on the outer side wall of the centralizer rigid body. The wear-resistant strips are spirally arranged with a helical angle of 30 to 45 degrees. The spacing between the wear-resistant strips is 15 to 25 mm. The wear-resistant strips have a length of 35 to 55 mm and a width of 20 to 30 mm. The present invention also provides a manufacturing method and application of the diamond-impregnated centralizer. The diamond-impregnated centralizer of the present invention has good wear resistance and flow conductivity.

Description

Technical Field

[0001] The present invention relates to the field of centralizers, and in particular to a diamond-impregnated centralizer and a manufacturing method and application thereof. Background Art

[0002] my country is experiencing rapid growth in oil drilling, geological prospecting, deep-earth scientific drilling, and exploration and development of new energy sources, such as hot dry rocks. Vertical drilling is the primary method of drilling in these diverse projects. Therefore, the lower drill string must be rigid, straight, and full. Most drill string installations incorporate two to four centralizers to ensure a constant vertical position between the drill string and the wellbore, preventing wellbore bending and tilting, minimizing drill string wear, and reducing wellbore accidents. Furthermore, drill string with centralizers can also be used in deviated wellbore drilling, ensuring the wellbore follows the planned trajectory and achieves the desired target. The structural performance and quality of the centralizer determine the quality of the drilled wellbore. Therefore, drill string centralizers play an irreplaceable role.

[0003] In modern deep geological drilling, rope coring drilling technology is vigorously promoted to improve drilling efficiency. It is also necessary to design drill tools with "rigid", "straight" and "full" structures. It is required to set up high-quality stabilizers for use with diamond rope coring drill tools, and use drill tools with a lower reamer and an upper stabilizer for drilling. The upper stabilizer cooperates with the lower reamer to effectively improve the "rigid", "straight" and "full" performance of the rope coring drill tool, which mainly plays the role of straightening the drill tool and can also play a certain role in repairing the hole. In this way, the advantages of rope coring drilling can be fully utilized, the quality of drilling and coring can be significantly improved, the life of the drill tool can be prolonged, and the drilling safety can be enhanced.

[0004] The centralizer mainly plays the role of centralizing the drill bit and can also play the role of trimming the well wall. At present, the centralizers used in oil drilling mainly use carbide blocks as abrasives. The manufacturing methods and performance characteristics of the centralizer are analyzed as follows:

[0005] (1) The stabilizer is made of cemented carbide and formed by a pressureless impregnation method. The abrasive particles of this type of stabilizer are coarse and long, and the wear resistance is high, but the cutting effect is very unsatisfactory, the ability to repair the hole wall is extremely low, and the wear resistance is far inferior to that of diamond-impregnated wear-resistant strips, which significantly affects the drilling effect. At the same time, the stabilizers used in oil drilling are all straight strips without exception, and the fit with the well wall is not ideal. Not only do they wear quickly, but the outer diameter error of the stabilizer is large, the operation is not stable, and there is a lot of vibration during drilling, which directly affects the stable operation of the stabilizer, shortens its service life, and increases safety hazards in the well.

[0006] (2) Using cemented carbide as the abrasive material for the wear-resistant strips of the centralizer, hot pressing and sintering methods are used to prefabricate the wear-resistant strips of the centralizer of a certain specification and shape. The prefabricated wear-resistant strips of the centralizer are welded into the annular grooves of the centralizer steel body by high-frequency welding and other methods to form the centralizer. This type of centralizer belongs to secondary forming. This method has a slightly lower cost for manufacturing the centralizer and a higher production efficiency. However, its disadvantage is that the annular welding grooves are milled on the centralizer steel body, which significantly reduces the strength of the centralizer steel body. There have been many cases of the centralizer steel body breaking, causing accidents in the hole. At the same time, cemented carbide as the wear-resistant material of the wear-resistant strips is far less wear-resistant than diamond. Therefore, the application of this type of centralizer is relatively limited. It has the shortcomings of non-pressure impregnated cemented carbide centralizers and is not suitable for drilling in deep wells or for use in rope coring drilling. Summary of the Invention

[0007] The present invention aims to provide a diamond-impregnated centralizer and a manufacturing method and application thereof. The diamond-impregnated centralizer has good wear resistance and flow conductivity.

[0008] The present invention provides a diamond-impregnated centralizer, comprising: a centralizer rigid body and a plurality of wear-resistant strips;

[0009] The plurality of wear-resistant strips are distributed in a ring shape on the outer side wall of the centralizer rigid body; the wear-resistant strips are arranged in a spiral shape, and the helix angle is 30 to 45 degrees; the spacing between the wear-resistant strips is 15 to 25 mm; the length of the wear-resistant strips is 35 to 55 mm, and the width is 20 to 30 mm.

[0010] The present invention also provides a method for manufacturing a diamond-impregnated centralizer, which is used to manufacture the above-mentioned diamond-impregnated centralizer, comprising the following steps:

[0011] S1, machining a spiral groove on the outer side of the centralizer rigid body;

[0012] S2. Electroplating the wear-resistant strip in the spiral groove using a pulsed diamond electroplating process; wherein the wear-resistant strip includes a first layer of diamond, a second layer of diamond, and a third layer of diamond electroplated sequentially from the inside to the outside.

[0013] Furthermore, in step S2, the electroplating method of the first layer of diamond is as follows:

[0014] Add 50-60 mesh diamond abrasive into the electroplating tank, and use bidirectional square wave pulse or non-interrupted pulse commutation to electroplate the first layer of diamond in the spiral groove; wherein the forward current density is 0.010-0.012A / cm 2 , time is 12~18ms; reverse current density is 0.022~0.025A / cm 2 , time is 1.2~1.6ms; composite pulse plating time is 8~9h;

[0015] Furthermore, in step S2, the electroplating method of the second diamond layer is as follows:

[0016] Add 30-40 mesh diamond abrasives into the electroplating tank, and electroplate a second layer of diamond on the first layer of diamond using bidirectional square wave pulses or non-interrupted pulse commutation; wherein the forward current density is 0.012-0.014 A / cm 2 , time is 16~20ms; reverse current density is 0.023~0.027A / cm 2 , time is 1.3~1.8ms; composite pulse plating time is 11~12h;

[0017] Furthermore, in step S2, the electroplating method of the third layer of diamond is as follows:

[0018] Add 80-100 mesh diamond abrasives into the electroplating tank, and electroplate a third layer of diamond on the second layer of diamond using bidirectional square wave pulses or non-interrupted pulse commutation; wherein the forward current density is 0.009-0.011 A / cm 2 , time is 12~16ms; reverse current density is 0.018~0.022A / cm 2 , time is 1.2~1.5ms; composite pulse plating time is 5~7h.

[0019] Furthermore, the composition of the electroplating solution in the pulse electroplating diamond process and its components include: 40-62 g / L zinc sulfate, 36-58 g / L nickel sulfate, 8-11 g / L ferrous sulfate, 220-280 g / L potassium pyrophosphate, and 12-22 g / L potassium sodium tartrate.

[0020] Furthermore, the pH value of the electroplating solution is 8.0-8.8, and the temperature is 32-45°C.

[0021] Furthermore, the electroplating solution in the pulsed diamond electroplating process circulates and simultaneously vibrates the centralizer support in the electroplating solution; wherein, the flow rate of the electroplating solution is 3 to 5 cm / s, the vibration frequency is 30 to 45 times / min, and the amplitude is 1.5 to 2.0 cm.

[0022] Furthermore, after step S2, the following steps are further included:

[0023] S3. Performing a dehydrogenation embrittlement treatment on the centralizer rigid body electroplated with the wear-resistant strips; wherein the dehydrogenation embrittlement treatment is performed at a temperature of 180-200° C. and for a time of 1.5-2.0 h.

[0024] The present invention also provides an application of the diamond-impregnated centralizer in well drilling and / or wireline coring drilling.

[0025] The beneficial effects of the technical solution provided by the embodiments of the present invention are as follows: the diamond-impregnated centralizer in the embodiments of the present invention is capable of effectively improving the wear resistance and flow conductivity of the centralizer by arranging spiral wear-resistant strips on the outer side wall of the centralizer rigid body, with a spiral angle of 30 to 45° and a spacing between the wear-resistant strips of 15 to 25 mm; the length of the wear-resistant strips is 35 to 55 mm and the width is 20 to 30 mm. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 A schematic structural diagram of a diamond-impregnated centralizer in one embodiment of the present invention;

[0027] Figure 2 for Figure 1 Schematic diagram of the cross-sectional structure of the diamond-impregnated centralizer along the AA direction;

[0028] Figure 3 for Figure 1 Schematic diagram of the structure of the wear strip 4 in the diamond-impregnated centralizer;

[0029] Figure 4 A schematic diagram of the time-current relationship of bidirectional square wave pulse electroplating in an embodiment of the present invention;

[0030] Among them, 1. Centralizer steel body; 2. Centralizer connection external thread; 3. Centralizer connection internal thread; 4. Wear-resistant strip; 5. Single crystal diamond; 6. Wear-resistant strip positioning spiral axis; 7. Drain trough. DETAILED DESCRIPTION

[0031] The preferred embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings, wherein the accompanying drawings constitute a part of this application and are used together with the embodiments of the present invention to illustrate the principles of the present invention, and are not used to limit the scope of the present invention.

[0032] It should be noted that, in the embodiment of the present invention, the specification of the oil drilling drill bit is 8-1 / 2"

[0033] Taking a drill bit with a diameter of 216 mm (i.e., a drill bit with a diameter of 216 mm) as an example, a centralizer steel body of this specification is designed and processed, and the structure and manufacturing method of the diamond-impregnated centralizer of the present invention are explained using this centralizer rigid body as an example.

[0034] refer to Figures 1 to 3 , an embodiment of the present invention provides a diamond-impregnated centralizer, comprising: a centralizer rigid body 1 and a plurality of wear-resistant strips 4;

[0035] The plurality of wear-resistant strips 4 are distributed in a ring shape on the outer side wall of the centralizer rigid body 1; the wear-resistant strips 4 are arranged in a spiral shape, and the helix angle is 30 to 45°; the spacing between the wear-resistant strips 4 is 15 to 25 mm; the length of the wear-resistant strips 4 is 35 to 55 mm, and the width is 20 to 30 mm.

[0036] For example, in this embodiment, the helix angle of the wear-resistant strip 4 is 30°; the width of the wear-resistant strip 4 is 22 mm and the length is 45 mm; the number of the wear-resistant strips 4 is 12, which are evenly spaced and distributed on the same circumference of the outer wall of the centralizer rigid body 1; the outer side of the centralizer rigid body 1 is provided with a connecting external thread 2, and the inner side is provided with a connecting internal thread 3; the wear-resistant strip 4 is inlaid with single crystal diamond 5; the gap between the wear-resistant strips 4 is a drainage trough for discharging drilling fluid.

[0037] The present invention also provides a method for manufacturing a diamond-impregnated centralizer, which is used to manufacture the above-mentioned diamond-impregnated centralizer, comprising the following steps:

[0038] S1. Processing a spiral groove on the outer side of the centralizer rigid body.

[0039] For example, in this embodiment, the helix angle α of the helical axis 6 on the centralizer steel body is 30°, and 12 spiral grooves with a depth of 0.5 mm are milled out, with specifications of 22 mm in width and 45 mm in length.

[0040] In step S1, the centralizer body with the spiral groove processed needs to be pre-treated before plating. Specifically, the parts other than the spiral groove of the centralizer body are degreased and derusted, and then cleaned in hot water and cold water respectively; then wrapped and insulated; and then electrochemical degreasing and anodic activation are performed. After being cleaned again with hot water and cold water respectively, it can enter the electroplating tank for electroplating.

[0041] S2. Electroplating the wear-resistant strip in the spiral groove using a pulsed diamond electroplating process; wherein the wear-resistant strip includes a first layer of diamond, a second layer of diamond, and a third layer of diamond electroplated sequentially from the inside to the outside.

[0042] For example, in this embodiment, the parameters of the abrasive in the wear-resistant strip are selected as follows: three different diamond particle sizes of 30-40 mesh, 50-60 mesh and 80-100 mesh, with a percentage concentration of 92%, and the grade of diamond is SMD40; wherein, the particle size of the diamond in the first layer of diamond is 50-60 mesh, the particle size of the diamond in the second layer of diamond is 30-40 mesh, and the particle size of the diamond in the third layer of diamond is 80-100 mesh.

[0043] Specifically, the specific method of electroplating the first layer of diamond, the second layer of diamond and the third layer of diamond to produce the wear-resistant strip is as follows:

[0044] First, the centralizer body was placed in an electroplating tank and subjected to impact electroplating for 3 minutes at a current density of 0.24 A / cm 2 ; Then pre-plated for 30 minutes, current density 0.010A / cm 2 ;

[0045] Then, 50-60 mesh diamond abrasive is added to the electroplating tank, and the first layer of diamond is electroplated in the spiral groove using bidirectional square wave pulse or non-interrupted pulse commutation; wherein the forward current density is 0.010A / cm 2 , time is 18ms; reverse current density is 0.022A / cm 2 , time is 1.5ms; composite pulse plating time is 8h.

[0046] Then, 30-40 mesh diamond abrasive is added to the electroplating tank, and a second layer of diamond is electroplated on the first layer of diamond using bidirectional square wave pulses or non-interrupted pulse commutation; wherein the forward current density is 0.012A / cm 2 , time is 20ms; reverse current density is 0.025A / cm 2 , time is 1.8ms; composite pulse plating time is 11h.

[0047] Finally, 80-100 mesh diamond abrasives are added to the electroplating tank, and a third layer of diamond is electroplated on the second layer of diamond using bidirectional square wave pulses or non-interrupted pulse commutation; wherein the forward current density is 0.009 A / cm 2 , time is 16ms; reverse current density is 0.018A / cm 2 , time is 1.2ms; composite pulse plating time is 5h.

[0048] Figure 4 Schematic diagram of the time-current relationship of bidirectional square wave pulse electroplating in this embodiment.

[0049] As a variation of this embodiment, in the process of electroplating the first layer of diamond, the forward current density is 0.011A / cm 2 , time is 14ms; reverse current density is 0.023A / cm 2 , time is 1.6ms; composite pulse plating time is 8.5h; in the process of electroplating the second layer of diamond, the forward current density is 0.013A / cm 2 , time is 18ms; reverse current density is 0.023A / cm 2 , time is 1.5ms; composite pulse plating time is 11.5h; in the process of electroplating the third layer of diamond, the forward current density is 0.010A / cm2 , time is 14ms; reverse current density is 0.020A / cm 2 , time is 1.3ms; composite pulse plating time is 6h.

[0050] As a variation of this embodiment, in the process of electroplating the first layer of diamond, the forward current density is 0.010 A / cm 2 , time is 12ms; reverse current density is 0.025A / cm 2 , time is 1.6ms; composite pulse plating time is 9h; in the process of electroplating the second layer of diamond, the forward current density is 0.014A / cm 2 , time is 16ms; reverse current density is 0.027A / cm 2 , time is 1.3ms; composite pulse electroplating time is 12h; in the process of electroplating the third layer of diamond, the forward current density is 0.011A / cm 2 , time is 12ms; reverse current density is 0.022A / cm 2 , time is 1.5ms; composite pulse plating time is 7h.

[0051] S3. Performing a dehydrogenation embrittlement treatment on the centralizer rigid body electroplated with the wear-resistant strips; wherein the dehydrogenation embrittlement treatment is performed at a temperature of 210° C. and for a time of 2.0 h.

[0052] In step S3, after the dehydrogenation is completed, the centralizer plated with the wear-resistant strip is cooled to room temperature and then taken out, and is trimmed and decorated to complete the manufacture of the diamond-impregnated centralizer.

[0053] For example, in this embodiment, the plating solution in the pulsed diamond plating process circulates and the centralizer support is vibrated at the same time; wherein the flow rate of the plating solution is 3 cm / s, the vibration frequency is 30 times / min, and the amplitude is 1.5 cm

[0054] Specifically, in this embodiment, the composition of the electroplating solution in the pulse electroplating diamond process and its components include: 55 g / L zinc sulfate, 42 g / L nickel sulfate, 9 g / L ferrous sulfate, 240 g / L potassium pyrophosphate, and 16 g / L potassium sodium tartrate; the pH value of the electroplating solution is 8.2, the temperature is 38°C, and the solvent is water.

[0055] As a variation of this embodiment, the composition of the electroplating solution and its components include: 40 g / L zinc sulfate, 36 g / L nickel sulfate, 8 g / L ferrous sulfate, 220 g / L potassium pyrophosphate, and 12 g / L potassium sodium tartrate; the pH value of the electroplating solution is 8.0, the temperature is 32°C, and the solvent is water.

[0056] As a variation of this embodiment, the composition of the electroplating solution and its components include: 62 g / L zinc sulfate, 58 g / L nickel sulfate, 11 g / L ferrous sulfate, 280 g / L potassium pyrophosphate, and 22 g / L potassium sodium tartrate; the pH value of the electroplating solution is 8.8, the temperature is 45°C, and the solvent is water.

[0057] The diamond-impregnated centralizer in the embodiment of the present invention can be used in the fields of well drilling, geological exploration wireline coring drilling, etc.

[0058] The diamond-impregnated centralizer in the embodiment of the present invention has the following advantages:

[0059] (1) Pulse plating uses bidirectional square wave pulses, without interrupting pulse reversing plating, which is scientific, reasonable and practical. The different properties of forward and reverse plating play a role: the reverse pulse can dissolve and remove the burrs of the electrodeposited layer obtained by the forward pulse, improve the thickness distribution of the complex coating, and thus obtain a coating with fine crystals, smoothness and brightness; at the same time, the bonding force between the wear-resistant strip and the steel body of the centralizer is strong, far exceeding the effect of ordinary DC plating.

[0060] (2) Experimental analysis shows that the zinc-nickel-iron coating has a fine grain size, is dense, bright and uniform, and can significantly reduce the porosity of the coating. Detected by a DA-300MP density meter, its actual density can reach 98.7% of the theoretical density, which is beneficial to improving wear resistance and corrosion resistance. For diamond products electroplated by conventional methods, the actual density of the coating can reach up to 97% of the theoretical density. The performance of the pulse electroplated wear-resistant strips in the present invention is higher than that of ordinary electroplated nickel-iron and other alloy wear-resistant strips. At the same time, it can ensure that the diamonds in the wear-resistant strips are in a micro-edged state, and have good hole repairing and hole protection effects.

[0061] (3) Since the wear-resistant strips in the embodiment of the present invention are arranged in a spiral shape, they can be in full-area and sequential contact with the well wall during drilling, and the contact arc surface with the well wall in the circumferential direction of the drill bit is large, and the stability is significantly improved; indoor tests have shown that the vibration and noise of the drill bit are basically eliminated, and there is no instability of the drill bit; within the same test time, the wear of the diamond-impregnated stabilizer in the embodiment of the present invention is significantly reduced; through a field drilling comparison test in a certain oil field, the working life of the diamond-impregnated stabilizer in the embodiment of the present invention is not less than 2200 to 2500 meters, without any abnormal wear precedent, which is significantly higher than the maximum service life of 1200 to 1500 meters of ordinary straight strip type stabilizers made of carbide abrasives.

[0062] (4) The diamond-impregnated centralizer in the embodiment of the present invention has good conductivity, low flow resistance of the flushing fluid, and high return flow rate of the flushing fluid. According to tests, the average return flow rate is increased by about 0.18 m / s, the effect of removing rock powder and cooling the drill tool is improved, and the wear of the drill tool is reduced; it has good adaptability to different rock formations and drilling conditions, and has obvious practical effects; the stability and wear resistance during drilling are much higher than other existing conventional types of centralizers.

[0063] (5) The wear-resistant strip of the diamond-impregnated straightener in the embodiment of the present invention is a zinc-nickel-iron alloy, which has high toughness, hardness and wear resistance. Compared with the wear-resistant strips prepared by nickel-cobalt plating solution and nickel-iron plating solution, the cost is lower, which can reduce the cost by 30% and 24% respectively. The pulse electroplated zinc-nickel-iron alloy matrix diamond test piece in the embodiment of the present invention is tested by a special tension ring. The strength of the diamond-impregnated strip is 25-27% higher than that of the nickel-cobalt and nickel-iron alloy test pieces. The diamond-impregnated strip in the embodiment of the present invention has high strength and good toughness, and the quality and service life of the wear-resistant strip are bound to be improved.

[0064] (6) The matrix of the wear-resistant strip in the diamond-impregnated straightener in the embodiment of the present invention is an electroplated zinc-nickel-iron alloy matrix. The increase or decrease in the content of zinc, nickel and iron in the solution will affect the percentage of each component metal in the coating; the percentage content of zinc in the alloy increases with the increase of the zinc content in the solution, and at the same time, the content of nickel and iron decreases accordingly; and the percentage content of nickel in the alloy increases with the increase of the nickel content in the solution, and at the same time, the iron content in the alloy also increases accordingly; therefore, the electroplating solution in the present invention is conducive to adjusting the performance of the straightener wear-resistant strip and achieving an ideal wear-resistant effect.

[0065] (7) When the contents of zinc, nickel and iron in the electroplating solution remain unchanged, as the temperature of the plating solution increases, the nickel content in the electroplated alloy will increase, and the zinc and iron contents will decrease accordingly; in order to increase the nickel content and improve the wear resistance of the stabilizer, the temperature of the electroplating solution can be used to adjust the plating solution temperature to 40-45°C to obtain wear-resistant strips with a higher nickel content, thereby improving the wear resistance of the wear-resistant strips.

[0066] (8) By adjusting the content ratio of the plating solution components, different ratios of zinc-nickel-iron alloy in the wear-resistant strip matrix alloy can be achieved; under the condition that nickel and cobalt resources are relatively scarce in my country, nickel-iron can be used to replace cobalt, and zinc-iron can be used to replace nickel. In combination with pulse electroplating technology, good performance of the diamond stabilizer can also be obtained, which significantly reduces the manufacturing cost of the stabilizer and achieves good economic and technical indicators.

[0067] (9) In the manufacturing method of the diamond-impregnated centralizer in the embodiment of the present invention, the zinc-nickel-iron electroplating solution is combined with optimized pulse electroplating process parameters. The electroplated zinc-nickel-iron alloy diamond-impregnated centralizer can achieve high hardness and good toughness, will not break during operation, has a firm diamond encapsulation, and has a reliable straightening effect. At the same time, by adjusting the ratio of the various components in the electroplating solution and the corresponding adjustment of the electroplating process parameters, the optimized content ratio of zinc, nickel, and iron can be adjusted to achieve the different hardness and wear resistance required by the centralizer wear-resistant strip, meeting the drilling needs under different conditions.

[0068] (10) The diamond grain sizes used in the diamond-impregnated straightener in the embodiment of the present invention are 35-40 mesh, 50-60 mesh and 80-100 mesh, and the diamond grade is SMD40 type single crystal diamond; the percentage concentration of diamond reaches 85-95%, and the diamond grain sizes are scientifically and reasonably matched. The coarse-grained diamond has high efficiency in trimming the hole wall, while the medium-grained diamond has the effect of trimming the hole wall and improving the wear resistance. The 80-100 mesh diamond can achieve the leveling effect of the straightener surface, and the 35-40 mesh fine-grained diamond can be effectively filled between the coarse-grained diamond and the medium-grained diamond, effectively connecting the coarse-grained diamond and the medium-grained diamond, while improving the wear resistance, so that the appearance of the diamond-impregnated straightener is improved; this enhances the hole repair quality of the straightener wear-resistant strip and improves the straightening effect and service life of the straightener.

[0069] (11) The structure of the diamond-impregnated straightener in the embodiment of the present invention is unique and scientific, which can realize the rigid, straight and full structure of the lower drill bit. The well wall after drilling is complete and smooth, the quality of the well wall is high, and no accidents occur in the well, which helps to improve drilling efficiency and significantly reduce drill wear; it can indirectly protect the drill bit and increase the service life of the drill bit; the pulse electroplating method and manufacturing process of the diamond-impregnated straightener in the embodiment of the present invention are obviously creative, the zinc-nickel-iron coating has good affinity with diamond, the encapsulated diamond is firm, and the matrix has high density; the diamond-impregnated straightener manufactured by the pulse electroplating method and process in the embodiment of the present invention has good use effect, low manufacturing cost and high production efficiency; it can be produced under the conditions of ordinary electroplating plant equipment, without adding new equipment, and the manufacture of a batch of straighteners can be completed within one day.

[0070] Any matters not mentioned above shall be subject to the existing technology.

[0071] In this document, directional terms such as front, back, top, and bottom are defined based on the positions of components in the accompanying drawings and relative to each other, and are intended only for clarity and convenience in describing the technical solution. It should be understood that the use of these directional terms should not limit the scope of protection claimed in this application.

[0072] In the absence of conflict, the above embodiments and features in the embodiments may be combined with each other.

[0073] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A diamond-impregnated centralizer, characterized in that: include: A centralizer rigid body and a plurality of wear-resistant strips; the plurality of wear-resistant strips are distributed in an annular shape on the outer wall of the centralizer rigid body; the wear-resistant strips are arranged in a spiral shape, and the helix angle is 30 to 45 degrees; the spacing between the wear-resistant strips is 15 to 25 mm; the length of the wear-resistant strips is 35 to 55 mm, and the width is 20 to 30 mm; the preparation method thereof comprises the following steps: S1, machining a spiral groove on the outer side of the centralizer rigid body; S2. Electroplating the wear-resistant strip in the spiral groove using a pulsed diamond electroplating process; wherein the wear-resistant strip includes a first layer of diamond, a second layer of diamond, and a third layer of diamond electroplated sequentially from the inside to the outside; The electroplating method of the first layer of diamond is as follows: Add 50-60 mesh diamond abrasive into the electroplating tank, and use bidirectional square wave pulse or non-interrupted pulse commutation to electroplate the first layer of diamond in the spiral groove; wherein the forward current density is 0.010-0.012A / cm 2 , time is 12~18ms; reverse current density is 0.022~0.025A / cm 2 , time is 1.2~1.6ms; composite pulse plating time is 8~9h.

2. The diamond-impregnated centralizer according to claim 1, characterized in that: In step S2, the electroplating method of the second diamond layer is as follows: Add 30-40 mesh diamond abrasives into the electroplating tank, and electroplate a second layer of diamond on the first layer of diamond using bidirectional square wave pulses or non-interrupted pulse commutation; wherein the forward current density is 0.012-0.014 A / cm 2 , time is 16~20ms; reverse current density is 0.023~0.027A / cm 2 , time is 1.3~1.8ms; composite pulse plating time is 11~12h.

3. The diamond-impregnated centralizer according to claim 2, characterized in that: In step S2, the electroplating method of the third layer of diamond is as follows: Add 80-100 mesh diamond abrasives into the electroplating tank, and electroplate a third layer of diamond on the second layer of diamond using bidirectional square wave pulses or non-interrupted pulse commutation; wherein the forward current density is 0.009-0.011 A / cm 2 , time is 12~16ms; reverse current density is 0.018~0.022A / cm 2 , time is 1.2~1.5ms; composite pulse plating time is 5~7h.

4. The diamond-impregnated centralizer according to any one of claims 2 to 3, characterized in that: The composition of the electroplating solution in the pulse electroplating diamond process and its components include: 40-62g / L zinc sulfate, 36-58g / L nickel sulfate, 8-11g / L ferrous sulfate, 220-280g / L potassium pyrophosphate, and 12-22g / L potassium sodium tartrate.

5. The diamond-impregnated centralizer according to claim 4, characterized in that: The pH value of the electroplating solution is 8.0-8.8, and the temperature is 32-45°C.

6. The diamond-impregnated centralizer according to claim 2, characterized in that: The electroplating solution in the pulse diamond electroplating process circulates and simultaneously vibrates the centralizer support in the electroplating solution; wherein the flow rate of the electroplating solution is 3 to 5 cm / s, the vibration frequency is 30 to 45 times / min, and the amplitude is 1.5 to 2.0 cm.

7. The diamond-impregnated centralizer according to claim 2, characterized in that: After step S2, the method further includes the following steps: S3. Performing a dehydrogenation embrittlement treatment on the centralizer rigid body electroplated with the wear-resistant strips; wherein the dehydrogenation embrittlement treatment is performed at a temperature of 180-200° C. and for a time of 1.5-2.0 h.

8. Use of the diamond-impregnated centralizer according to any one of claims 1 to 7 in well drilling and / or geological exploration wireline coring drilling.

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