A perforation method

Abstract

This invention belongs to the field of oil and gas well production technology, specifically relating to a perforation method, including: during the perforation operation, when the perforating gun is lowered to the perforation section, the tubing is pressurized for perforation to complete the perforation operation; the size and ammunition quantity of the perforating gun are designed as follows: the maximum outer diameter of the perforating gun is determined based on the inner diameter of the casing hanger and the inner diameter of the hanging casing; the maximum length of the perforating gun rigidly passing through the casing is calculated based on the maximum outer diameter of the perforating gun, the inner diameter of the hanging casing, and well inclination data to obtain the maximum length of the perforating gun; the standard type of the perforating gun is determined based on the maximum outer diameter of the perforating gun; the perforating gun charge quantity is increased by a set charge quantity based on the standard charge quantity corresponding to the determined standard type of perforating gun. Therefore, this invention solves the problems in the prior art such as perforating gun jamming during startup and shutdown and multiple perforation attempts due to the influence of horizontal well inclination, double casing, and casing size.

Description

Technical Field

[0001] This invention belongs to the field of oil and gas well production technology, and specifically relates to a perforation method. Background Technology

[0002] Horizontal wells employ a three-stage wellbore structure. Suspended casing completion is one of the main completion methods for horizontal wells currently. The vertical section of the horizontal well uses 7″ casing for cementing, while the horizontal section uses 4″ casing suspended within the 7″ casing. 1 / 2″ naked eye pre-installed tubing or suspension 4 1 For 2″ casing completion, perforation is required during production in the overlapping section between the 7″ casing and the suspended casing. This section typically has an inclination greater than 65°, a dogleg greater than 3.5 degrees / 30m, and is a double-casing configuration. The hanger inner diameter range is... Inner diameter of suspension sleeve Some horizontal well hangers have a necking effect relative to the hanging casing, resulting in gun body expansion after perforation, a higher risk of gun jamming during tripping, limited perforator size, lower perforation completion coefficient, increased perforation times, and increased perforation costs.

[0003] Existing Chinese invention patents, including the authorized publication number CN105840151B, "Perforated String and Perforated String Depth Correction and Perforation Method," and published documents such as "Research on the Penetration Performance of Double-Casing Perforation in Offshore Oil and Gas Fields" and "Research and Application of Deep Penetration Transmission Technology in Small Boreholes," all propose conventional horizontal well perforated string structures, laboratory research on double-casing perforation, and research on deep penetration transmission technology in small wellholes. However, none of these publications mention 4... 1 / 2″ Research and practice on the deviated section of the casing, the double-layer casing deep penetration through-hole string and method.

[0004] Currently, existing horizontal well perforation strings and methods mainly include: First, double-casing perforation is limited to theoretical research, qualitatively analyzing the impact of perforation ammunition quantity, casing wall thickness, and casing steel grade on the perforation perfection coefficient, but lacking quantitative research and the minimum perforation gun and related parameters for double-casing penetration limits, thus offering no guidance for wells with limited casing inner diameter; Second, the use of a Q73mm perforation gun and SDP32RDX16 perforation ammunition, suitable for 4″ and 4″ diameter wells. 1 / 2″ internal perforation through the casing can be achieved with a hanger, reducing the risk of gun jamming. The length of the perforating gun can be increased, reducing the number of perforations. However, the perforation accuracy of double-casing perforations is lower, and sometimes the casing may not even be penetrated. Thirdly, it uses a Q89mm perforating gun and SDP36RDX18 and SDP36RDX25 perforating cartridges, suitable for 4... 1 / 2″ and 5 1 / 2″ casing internal perforation, but in the large well deviation section, when the hanger inner diameter is smaller than When necking occurs, the risk of gun jamming after perforation due to gun diameter expansion is high. At the same time, the length of the perforating gun is limited, and for the same perforation section length, the number of perforations increases, thus increasing the perforation cost. Fourth, for wells with large inclination and small-diameter casing wells, there is no systematic perforating gun design method. The perforating gun size and perforating cartridge are selected based on experience, resulting in a low perforation perfection coefficient, a high risk of gun jamming, frequent gun insertion and obstruction, and a large number of perforations, leading to high perforation costs. Fifth, in perforation operations of old wells, due to formation depletion, annular pressurized perforation cannot be achieved. At the same time, during the process of lowering the perforating gun, wellbore fluid enters the perforating string, and sediment and impurities can easily clog the section of the well above the detonator, making it impossible to pressurize and detonate the perforating gun. Summary of the Invention

[0005] The purpose of this invention is to provide a perforation method to solve the problem of low perforation perfection coefficient in the prior art, which leads to multiple perforation passes.

[0006] To solve the above-mentioned technical problems, the technical solution provided by this invention and the corresponding beneficial effects of the technical solution are as follows:

[0007] A perforation method according to the present invention includes the following steps:

[0008] During the perforation operation, when the perforating gun is lowered to the perforation section, the oil pipe pressurizes the perforation to complete the perforation operation;

[0009] The length of the perforating gun is designed based on the maximum length of the perforating gun, which is the maximum length through which the perforating gun rigidly passes within the casing. This maximum length is calculated based on the maximum outer diameter of the perforating gun, the inner diameter of the suspended casing, and well inclination data, including the following calculation formula:

[0010]

[0011]

[0012] In the formula: L is the maximum length of the perforating gun, b is the outer diameter of the perforating gun, a is the inner diameter of the suspension casing, R is the radius of curvature inside the wellbore, and K is the rate of change of the full angle at the arc in the well inclination data.

[0013] The beneficial effects of the above technical solution are as follows: Firstly, this invention obtains the maximum length of the perforating gun based on the maximum outer diameter of the perforating gun, the inner diameter of the suspended casing, and well inclination data. This invention uses a 5mm expansion of the perforating gun after perforation as the outer diameter of the perforating string for calculation. Within different casings, based on the well inclination angle and the dogleg angle data (the rate of change of the full arc angle) obtained from the well inclination angle, the maximum perforating gun length can be calculated, reducing the number of perforations and lowering the cost of perforation. Secondly, the method of this invention has universal applicability to the specific design methods of perforation in large well inclination sections, double-layer casing perforation, and perforation within small-diameter casings. The design is simple, easy to operate, and has strong applicability and high promotional value.

[0014] Furthermore, the maximum outer diameter of the perforating gun is determined based on the inner diameter of the casing hanger and the inner diameter of the hanging casing. The method for determining the maximum outer diameter of the perforating gun includes:

[0015] If the inner diameter of the casing hanger is greater than or equal to the inner diameter of the casing, then the maximum outer diameter of the perforating gun is less than or equal to the inner diameter of the casing minus the maximum expansion diameter of the perforating gun after perforation, minus the gap between the perforating gun expansion diameter and the inner diameter of the casing.

[0016] If the inner diameter of the casing hanger is smaller than the inner diameter of the hanging casing, the maximum outer diameter of the perforating gun is less than or equal to the distance between the inner diameter of the casing hanger minus the maximum expansion diameter of the perforating gun after perforation, minus the expansion diameter of the perforating gun, and the inner diameter of the casing hanger.

[0017] The beneficial effects of the above technical solution are as follows: This invention determines the maximum outer diameter of the perforating gun based on the inner diameter of the casing hanger and the inner diameter of the hanging casing, thereby achieving optimized design of the perforating gun size and solving the problem of gun body expansion after perforation in large well inclination sections and small-diameter casings in horizontal wells, which poses a risk of gun jamming.

[0018] Furthermore, the maximum expansion diameter of the perforating gun after perforation is 5mm, the gap between the perforating gun after expansion and the inner diameter of the casing is 6mm, and the gap between the perforating gun after expansion and the inner diameter of the casing hanger is 6mm.

[0019] The beneficial effects of the above technical solution are as follows: The present invention takes into account the maximum expansion diameter of the perforating gun after perforation of 3-5mm, and the gap between the perforating gun and the inner diameter of the casing after expansion of the perforating gun is ≥6mm or the gap between the perforating gun and the inner diameter of the casing after expansion of the perforating gun is ≥6mm. By optimizing the design of the perforating gun size, the risk of gun jamming is eliminated, and the problem of gun jamming after perforation in the large inclination section of horizontal well and in the small diameter casing is solved.

[0020] Furthermore, the charge amount of the perforating gun is increased by a set charge amount based on the standard charge amount of the perforating gun corresponding to the standard type of perforating gun. The perforating gun with the increased charge amount can penetrate the casing and the deformation of the gun body's outer diameter is less than or equal to the distance between the perforating gun's expanded diameter and the inner diameter of the casing, or the distance between the perforating gun's expanded diameter and the inner diameter of the casing hanger. The standard type of the perforating gun is determined based on the maximum outer diameter and maximum length of the perforating gun.

[0021] The beneficial effects of the above technical solution are as follows: The present invention selects the standard type of perforating gun based on the maximum outer diameter of the perforating gun, and adds a set charge amount on the basis of the standard charge amount of the perforating gun corresponding to the selected standard type of perforating gun. It adopts a small gun with a large charge design, which solves the problem that the perforation perfection coefficient of double casing is low due to the influence of well size in small diameter casing. It achieves double casing penetration and avoids the risk of severe deformation or gun explosion of the perforating gun.

[0022] Furthermore, if the standard type of the perforating gun is determined to be a Q73mm perforating gun, then the range of the perforating gun charge w is 18g≤w<20g.

[0023] Furthermore, the perforating gun detonator is provided with a pressure relief hole, the diameter of which ranges from 10 mm to 12 mm.

[0024] The beneficial effects of the above technical solution are as follows: This invention solves the problems of old wells being unable to achieve annular pressure testing and small wellbore perforation potentially encountering obstruction or jamming, making circulation washing and well unblocking impossible. It designs tubing positive pressure perforation, and the detonator is designed with a pressure relief hole. After perforation, the pressure relief hole can be opened to achieve reverse circulation washing, or the perforation string can be directly used as the oil and gas testing string after perforation, avoiding repeated string pulling and pulling, reducing perforation risk and operating costs.

[0025] Furthermore, there are two or three pressure relief holes, which are evenly distributed circumferentially on the detonator. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the horizontal well small-diameter double-casing wellbore structure of the present invention;

[0027] Figure 2 This is a schematic diagram of the detonator structure of the present invention;

[0028] Figure 3 This is a flowchart illustrating the perforation method design of the present invention;

[0029] Figure 4 This is a schematic diagram of the perforation string structure of the present invention.

[0030] In the diagram: 1. Surface casing; 2. Technical casing; 3. Casing hanger; 4. Double-layer casing perforation section; 5. Suspended casing; 6. Ball-throwing sleeve; 7. Perforation section; 8. Open-hole packer; 11-1. Upper connector; 11-2. Circulation hole; 11-3. Pin; 11-4. Charging pin; 11-5. Detonator; 11-6. Lower connector; 9. Thickened chamfered tubing string; 10. Upper coupling; 11. Detonator; 12. Perforation gun; 13. Lower coupling; 14. Thickened chamfered tubing; 15. Guide cone. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0032] An embodiment of a perforation method:

[0033] An embodiment of the perforation method of the present invention, such as... Figure 1As shown in the figure, the casing includes a surface casing 1, a technical casing 2, a casing hanger 3, a double-casing perforated section 4, a suspended casing 5, a ball-operated sliding sleeve 6, a perforated section 7, and an open-hole packer 8. In this embodiment of the invention, the technical casing for the vertical section of the horizontal well uses a 7″ casing for cementing, and the horizontal section uses a 4″ casing suspended inside the 7″ casing. 1 / 2″ naked eye pre-installed tubing or suspension 4 1 For 2″ casing completions, perforation is required in the overlapping section between the 7″ casing and the suspended casing during production. This section typically has an inclination greater than 65°, a dogleg greater than 3.5° / 30m, and is a double-casing configuration. The hanger inner diameter ranges from φ92.5mm to φ105mm, while the suspended casing inner diameter is φ101.6mm. In some horizontal wells, the hanger has a necking relative to the suspended casing. Since the outer diameter of the perforating string is smaller than the outer diameter of the perforating gun, and the perforating gun expands after perforation, obtaining the outer diameter of the perforating gun is a primary consideration during operations. Finally, while bending of the perforating string poses no risk, bending of the perforating gun does, such as stuck pipe, detonation, and the initiator or fuse failing to ignite due to tension. Therefore, the length of the perforating gun is also a crucial factor during operations.

[0034] One perforation method of the present invention, such as Figure 3 As shown, it includes the following steps:

[0035] Step (1): Design of the perforation gun size.

[0036] Under a given wellbore size, to meet the perforation perfection factor of double-casing casing, the maximum outer diameter of the perforating gun is designed. This invention considers the expansion of the perforating gun after perforation, with a maximum expansion diameter of 3-5mm after perforation.

[0037] If the inner diameter of the casing hanger is greater than or equal to the inner diameter of the suspended casing (φ101.6mm), then the gap between the perforating gun and the inner diameter of the casing after expansion is greater than or equal to 6mm, and the maximum outer diameter of the perforating gun is less than or equal to the inner diameter of the casing (φ101.6mm - 5mm - 6mm) = φ90.6mm. If the inner diameter of the casing hanger is less than the inner diameter of the suspended casing (φ101.6mm), then the gap between the perforating gun and the inner diameter of the casing hanger after expansion is greater than or equal to 6mm, and the maximum design size of the perforating gun is less than or equal to the inner diameter of the casing hanger (-5mm - 6mm).

[0038] Under the condition that the perforating gun can be safely pulled out of the wellbore after perforation, the maximum length of the perforating gun is designed based on the rigidity of the perforating gun. That is, the maximum length of the perforating gun that can rigidly pass through the casing is calculated based on the given range of the perforating gun's outer diameter, the casing's inner diameter, and the well inclination data.

[0039] When calculating the maximum length of the rigid perforation gun in the casing, a very short local section of the wellbore in the inclined section can be regarded as a circular arc.

[0040] The total angle variation rate (dogleg) at the arc is calculated from the well inclination angle, which is obtained through measurement. Specifically, the dogleg is calculated at 30m intervals based on inclination data (depth, inclination angle, azimuth). The radius of curvature R within the wellbore is calculated based on the total angle variation rate K at the arc. Specifically, the total angle variation rate K at the arc, i.e., the dogleg, is used as a reference every 30m in this embodiment, providing practical guidance. The circumference is 2πR, corresponding to a central angle of 360°. Based on the well inclination data, the central angle corresponding to a 30m circumference is calculated as K. Therefore, the relationship between the 30m circumference and the central angle can be derived: That is, the relationship between the radius of curvature R and the dogleg K.

[0041]

[0042] The above formula can be simplified to:

[0043]

[0044] In the formula: R - radius of curvature inside the wellbore, in meters; K - rate of change of the full angle at the arc, in degrees / 30m.

[0045] Let L be the length through which the perforating gun assembly passes inside the casing (at which point the middle part of the assembly is tangent to the inner wall of the casing, and both ends are in contact with the casing wall), then:

[0046]

[0047] In the formula: L - tool length (maximum length of the perforating gun), in mm; b - tool outer diameter (maximum outer diameter of the perforating gun), in mm; a - sleeve inner diameter (inner diameter of the suspension sleeve), in mm.

[0048] This invention uses the 5mm expansion of the perforating gun after perforation as the outer diameter of the perforating string for calculation. In different casings, the maximum length of the perforating gun can be calculated based on the well inclination angle and dogleg data, thereby reducing the number of perforations and lowering the perforation cost.

[0049] Step (2): Design of the perforation projectile.

[0050] For a given perforating gun size, the charge amount should meet the perforation perfection factor; this applies to 7″ casing and 4″... 1 / 2″ double-layer overlapping casing section perforation, penetrates the casing and achieves the purpose of communicating with the reservoir. According to the actual perforation results on site, the amount of perforation ammunition should be ≥18g. This invention adopts the method of small gun loading large ammunition, reasonably controls the amount of perforation ammunition, and prevents the risk of serious diameter expansion and deformation of the perforation gun body after perforation, jamming, or even gun explosion.

[0051] For example, the standard Q73 perforating gun has a standard charge of 16g, which cannot meet the requirements for perforation through double-layered sleeves. The standard Q89 perforating gun has a standard charge of 24.5g, which can achieve perforation through double-layered sleeves. According to field tests, the Q73 perforating gun uses a perforating bullet with a charge of 18g. After perforation, the gun body expands by 3-5mm, which is controllable and can penetrate double-layered sleeves. When the charge is 20g, the gun body is severely deformed, posing a risk of gun explosion. Step (3): Design of the perforation tube structure.

[0052] The perforation string of this invention: such as Figure 4 As shown, the system includes an initiator 11 (with a built-in pressure relief port), a thickened chamfered tubing string 9, an upper coupling 10, a perforating gun 12, a lower coupling 13, a thickened chamfered tubing string 14, and a guide cone 15. ① The upper connector of the initiator connects to the thickened chamfered tubing string; ② The circulation port is closed before perforation. After the perforating gun is lowered into position, the tubing is pressurized to push the striker downwards, opening the lateral circulation port. Its advantages are: firstly, when the perforating gun expands after perforation, there is a possibility of obstruction or jamming. The circulation port can be used for well cleaning and unblocking, preventing downhole accidents; secondly, the perforating string can be used as a test gas production string, allowing formation fluids to enter the tubing and be produced through the circulation port. ③ The pin is used to lock the firing pin; ④ The firing pin can be pressed down by the oil pipe to cut off the pin and slide downward, hitting the detonator to detonate the perforation gun, and at the same time the firing pin moves down to open the side circulation hole; ⑤ The detonator is used to detonate the fuse; ⑥ The lower connector is used to connect the perforation gun barrel.

[0053] The detonator includes an upper connector 11-1, a circulation hole 11-2, a pin 11-3, a firing pin 11-4, a detonator 11-5, and a lower connector 11-6. The pressure relief holes on the detonator 11 of the perforating gun have a diameter ranging from 10 to 12 mm; preferably, the diameter of the pressure relief holes on the detonator is 10 mm. Two or three pressure relief holes can be provided, and they are evenly distributed circumferentially on the detonator.

[0054] Under the condition of positive pressure initiation of perforation by tubing, tubing is lowered in a sealed manner. Once the perforation gun reaches the perforation section, positive pressure perforation is initiated by tubing.

[0055] like Figure 2 As shown, this invention incorporates a pressure relief hole in the perforating gun detonator. On one hand, after perforation, an internal and external channel can be established in the tubing, allowing for reverse circulation well cleaning. On the other hand, because of the pressure relief hole in the perforating gun detonator, when the tubing is pressurized downwards, the striker shears off the pin, detonating the detonator and perforating. Continuing to pressurize the striker downwards opens the lateral pressure relief hole, allowing the perforating string to serve as a test gas string. Simultaneously, reverse circulation well cleaning can be performed to prevent gun jamming.

[0056] The effects of this invention will be illustrated below with specific experiments.

[0057] This invention was used in perforation operations of a small-diameter, double-cased horizontal well in an oilfield. The horizontal well has a three-stage wellbore structure. The vertical section uses 7″ casing cementing with an inner diameter of φ161.7mm. The horizontal section uses a 4″ casing suspended inside the 7″ casing. 1 / 2″ open-hole pre-installed tubing completion, with a hanger inner diameter of φ95.25mm, 4 1 The casing has an inner diameter of φ101.6mm ( / 2″), a perforated section length of 8-20m, a maximum wellbore inclination angle of 77°, and a maximum dogleg angle of 8.4° / 30m. The perforation design is as follows:

[0058] (1) Perforating gun size design: The maximum outer diameter of the perforating gun ≤ the inner diameter of the casing hanger φ95.25mm - 5mm - 6mm = φ84.25mm. According to the perforating gun standard, only the Q73mm perforating gun can be selected. Based on the rigidity principle calculation, with the inner diameter of the hanger φ95.25mm as the minimum inner diameter of the casing, in a perforation section with a maximum well inclination angle of 72° and a maximum dogleg degree of 8.4 degrees / 30m, the maximum rigidity of the Q73mm perforating gun in a single operation can reach a length of 7m.

[0059] (2) Perforation projectile design: According to the perforation gun design in (1), in order to achieve double-layer sleeve perforation, the Q73 perforation gun increases the perforation projectile charge and adopts the SDP32RDX18-1 perforation projectile.

[0060] (3) Perforation string structure design (from bottom to top): guide cone + φ73mm perforation gun + detonator (with pressure relief hole) + φ73mm thickened chamfered tubing connected to the wellhead.

[0061] Field application results of this perforation method: From 2019 to 2020, a total of 16 wells of this type of horizontal well underwent perforation repair measures in the double-casing section below the hanger and above target point A. The success rate of wellbore treatment and perforation was 100%. After the perforation repair measures, the maximum daily oil production of a single well was 12 tons / day, and the average cumulative production of a single well was 479 tons. The perforation cost was reduced by approximately RMB 1.58 million after the perforation method was optimized.

[0062] Table 1. Comparison of the effects of perforation methods before and after optimization.

[0063] Comparison Projects Before optimization After optimization Difference (later - earlier) Average perforation length per well (m) 12.1 12.1 0 Average number of perforations per well (times) 4 1.8 -2.2 Average length of a single perforation (m) 3 6.7 3.7 Longest single perforation length (m) 4 12 8 Average cost of perforation per well (in ten thousand) 18.1 8.2 -9.9

[0064] (1) The present invention provides a method for perforating double-layer casing in horizontal wells. It has universal applicability to the specific design methods for perforating in large wells with inclined sections, perforating double-layer casing, and perforating in small-diameter casing. The design is simple, easy to operate, and has strong applicability and high promotion value.

[0065] (2) This invention solves the problem of gun body expansion and gun jamming risk after perforation in large inclination sections and small diameter casings of horizontal wells. By optimizing the design of the perforating gun size, the longest perforating gun can be used for perforation, reducing the number of perforations and reducing the cost of perforation.

[0066] (3) This invention solves the problem that the perforation perfection coefficient of double-layer casing is low due to the influence of well barrel size in small-diameter casing. It adopts a small gun with a large bullet design, which can achieve double-layer casing penetration while avoiding the risk of severe deformation or gun explosion of the perforation gun.

[0067] (4) This invention solves the problems of old wells being unable to achieve annular pressure and small wells being unable to circulate and clean the well due to possible obstruction or jamming during perforation. It designs positive pressure perforation of the tubing and the detonator is designed with circulation holes. After perforation, the circulation holes can be opened to achieve reverse circulation well cleaning, or the perforation string can be directly used as the oil and gas testing string after perforation, avoiding repeated string pulling and pulling, reducing perforation risk and operating costs.

Claims

1. A method of perforating, characterized by: Includes the following steps: During the perforation operation, when the perforating gun is lowered to the perforation section, the oil pipe pressurizes the perforation to complete the perforation operation; The length of the perforating gun is designed based on the maximum length of the perforating gun, which is the maximum length by which the perforating gun rigidly passes through the casing. This maximum length is calculated based on the maximum outer diameter of the perforating gun, the inner diameter of the suspended casing, and well inclination data. ， ， In the formula: L is the maximum length of the perforating gun, b is the maximum outer diameter of the perforating gun, a is the inner diameter of the suspension casing, R is the radius of curvature inside the wellbore, and K is the rate of change of the full angle at the arc in the well inclination data.

2. The method of perforating of claim 1, wherein: The maximum outer diameter of the perforating gun is determined based on the inner diameter of the casing hanger and the inner diameter of the hanging casing. Methods for determining the maximum outer diameter of the perforating gun include: If the inner diameter of the casing hanger is greater than or equal to the inner diameter of the casing, then the maximum outer diameter of the perforating gun is less than or equal to the inner diameter of the casing minus the maximum expansion diameter of the perforating gun after perforation, minus the gap between the perforating gun expansion diameter and the inner diameter of the casing. If the inner diameter of the casing hanger is smaller than the inner diameter of the hanging casing, the maximum outer diameter of the perforating gun is less than or equal to the distance between the inner diameter of the casing hanger minus the maximum expansion diameter of the perforating gun after perforation, minus the expansion diameter of the perforating gun, and the inner diameter of the casing hanger.

3. The method of perforating of claim 2, wherein: The maximum expansion diameter of the perforating gun after perforation is 5mm. The gap between the perforating gun and the inner diameter of the casing after expansion is 6mm. The gap between the perforating gun and the inner diameter of the casing hanger after expansion is also 6mm.

4. The method of perforating of claim 1 or 2, wherein: The charge amount of the perforating gun is increased by a set charge amount based on the standard charge amount of the perforating gun of the standard type. The perforating gun with the increased charge amount can penetrate the casing and the deformation of the gun body outer diameter is less than or equal to the distance between the perforating gun after expansion and the inner diameter of the casing, or the distance between the perforating gun after expansion and the inner diameter of the casing hanger. The standard type of the perforating gun is determined based on the maximum outer diameter and the maximum length of the perforating gun.

5. The perforation method according to claim 4, characterized in that: If the standard type of the perforating gun is determined to be a Q73mm perforating gun, then the range of the perforating gun charge value w is 18g≤w<20g.

6. The perforation method according to claim 1, characterized in that: The perforating gun detonator is equipped with a pressure relief hole, the diameter of which ranges from 10 mm to 12 mm.

7. The perforation method according to claim 6, characterized in that: There are two or three pressure relief holes, which are evenly distributed circumferentially on the detonator.

Images