A safety performance evaluation method of a tubing string based on a perforating detonation effect

Abstract

This invention relates to the field of oil and gas well safety technology, and discloses a method for evaluating the safety performance of tubing strings based on the perforation detonation effect. The method includes: S1, determining the influencing factors of the perforation detonation effect on the tubing string; S2, calculating the detonation effect-related parameters of the tubing string based on the determined influencing factors; and S3, evaluating the safety of the tubing string based on the tubing string yield theory by comparing the detonation effect-related parameters and calculating the safety factor of the tubing string. Compared to traditional methods for designing tubing strings for perforation acidizing tests in ultra-deep, small-bore gas wells, which do not consider the influence of the perforation detonation effect on the string strength, this invention proposes a method for evaluating the safety performance of tubing strings based on the perforation detonation effect. This method considers the influence of transient impact loads on the string strength, making the design of oil and gas well tubing string structures more comprehensive and the safety performance considerations more complete, providing scientific theoretical support for the optimization of ultra-deep well tubing string structures.

Description

Technical Field

[0001] This invention relates to the field of oil and gas well safety technology, and specifically to a method for evaluating the safety performance of tubing strings based on the perforation detonation effect. Background Technology

[0002] As exploration and development gradually extend to deeper reservoirs, the difficulty of testing ultra-deep and ultra-high-pressure sulfur-bearing gas wells increases. Perforation operations increasingly employ high-density perforators and high-power perforation projectiles. Under high-energy detonation loads, the mechanical properties of the perforated tubing undergo significant changes, easily leading to problems such as tubing buckling instability, damage and fracture, and packer setting failure (see...). Figure 2 ).

[0003] Currently, conventional tubing string design is often based on statics principles or methods, without considering the impact of perforation detonation on the tubing string. The static load failure theory analysis under ideal conditions is inaccurate and cannot obtain the intrinsic connection between the local dynamic mechanical response of the structure and the overall instability under complex conditions. It cannot completely and effectively solve all the problems of gas well tubing string design, especially for wells that require the implementation of perforation acidizing test combined technology.

[0004] Conventional tubing string design primarily considers the effects of piston effect, buckling effect, bulging effect, and temperature effect, with dynamics studies limited to tubing string vibration. Research on the tubing string under perforation detonation effects is scarce, especially regarding its application in explosion mechanics, shock wave theory, and tubing string structural dynamics. Current domestic and international research mainly uses finite element numerical simulation to analyze wellbore fluid fluctuation pressure and the dynamic response of the perforated section tubing string, but this analysis does not consider the initial high pressure of the tubing string and fluid-structure interaction.

[0005] With the increasing number of ultra-deep small-diameter gas wells, the perforation detonation effect is particularly prominent. Conventional tubing force verification does not take into account the impact of the detonation effect, resulting in inadequate safety performance assessment of the tubing and posing a risk of damage to the tubing during construction. Summary of the Invention

[0006] To address the problems existing in the background technology, this invention proposes a safety performance evaluation method for oil tubing strings based on the perforation detonation effect. This method considers the influence of transient impact loads on the strength of the tubing string, making the structural design of oil and gas well tubing strings more comprehensive and the safety performance considerations more complete. It provides scientific theoretical support for the optimization of ultra-deep well tubing string structures and the formulation of oil testing safety control measures.

[0007] This invention is achieved through the following technical solution:

[0008] A method for assessing the safety performance of tubing strings based on the perforation detonation effect includes:

[0009] S1. Determine the influencing factors of the perforation detonation effect of the tubing string;

[0010] S2. Calculate the detonation effect parameters of the tubing string by identifying the influencing factors of the perforation detonation effect;

[0011] S3. By comparing the relevant parameters of the detonation effect, the safety of the tubing string is evaluated based on the tubing string yielding theory, and the safety factor of the tubing string is calculated.

[0012] As an optimization, the influencing factors of the perforation detonation effect include perforation projectile parameters, perforation parameters, perforation section casing parameters, perforation section tubing parameters, packer parameters, construction parameters, and reservoir parameters.

[0013] As an optimization, among which...

[0014] The parameters of the perforating projectile include: explosive type, charge mass, and charge density;

[0015] The perforation parameters include: perforation density, perforation phase, perforation diameter, perforation gun type, perforation top boundary, and perforation bottom boundary;

[0016] The parameters of the perforated section casing include: the outer diameter of the perforated section casing, the wall thickness of the perforated section casing, and the steel grade of the perforated section casing.

[0017] The parameters of the perforated section tubing include: the outer diameter of the perforated section tubing, the wall thickness of the perforated section tubing, and the steel grade of the perforated section tubing.

[0018] The packer parameters include: packer type, setting position, and tensile strength;

[0019] The construction parameters include: artificial well bottom, screen pipe top boundary, screen pipe bottom boundary, perforation fluid density, shock absorber location, and number of shock absorbers.

[0020] The reservoir parameters include: rock compressive strength, elastic modulus, Poisson's ratio, geostress, porosity, and permeability.

[0021] As an optimization, the detonation effect-related parameters include perforation detonation parameters, perforation detonation peak pressure, perforation pulsation pressure, detonation load acting on the bottom of the perforation tubing string, and stress on the perforation tubing string.

[0022] As an optimization, the perforation detonation parameters include detonation heat, detonation temperature, detonation volume, detonation velocity, and detonation pressure, wherein,

[0023] The explosive Q jr The calculation formula is:

[0024] Q jr =Q 2-3 +ΔnRM;

[0025] Among them, Q2-3 For isobaric detonation, Δn is the sum of the molar numbers of the gas components in the detonation products; R is the ideal gas constant; M is the relative molecular weight of the explosive.

[0026] The explosion temperature T jw The calculation formula is:

[0027] T jw =∑n i ΔE i ;

[0028] Where, n i For explosion product i, ΔE i The internal energy of the explosion product i;

[0029] The burst capacity V jv The calculation formula is:

[0030]

[0031] Among them, u i v is the number of moles of component i in the explosion product; j M is the number of moles of component j of the explosive; j is the molecular weight of component j of the explosive; m and n are the component numbers of the explosion products and the explosive, respectively.

[0032] The explosive speed V j The calculation formula is:

[0033]

[0034] Among them, v max ρ is the detonation velocity at the theoretical density of the shaped charge, ρ0 is the actual charge density, and ρ max This is the theoretical density of the explosive (single-element explosive or mixed explosive);

[0035] The explosive pressure p Jv The calculation formula is:

[0036] p Jv =15.58(φ) e W)ρ 2 0;

[0037] Where, φ e φ represents the explosive component in the shaped charge mixture; W represents the mass fraction of the explosive component in the shaped charge mixture.

[0038] As an optimization, the formula for calculating the peak pressure of the perforation detonation is as follows:

[0039]

[0040] Where, p jyPressure (explosive pressure); T jw V represents temperature (explosion temperature); n represents the number of perforation projectiles; V jv T is the volume (explosive capacity), n is the number of components in the explosive, and T is the explosive volume. b L represents the bottom hole temperature. j L is the length of the perforation section. d L is half the distance between the bottom of the perforated section and the bottom of the artificial well. s This refers to the length of the upper screen tube section.

[0041] As an optimization, the formula for calculating the perforation pulsation pressure is as follows:

[0042]

[0043] Where, p L Let p be the maximum pressure generated by bubble pulsation at a distance L from the burst point; L is the distance between the pressure point and the burst point. L should be greater than the critical burst depth, otherwise the calculation is meaningless. L <p max Only then does it have meaning, when p L >p max When taking p L =p max .

[0044] As an optimization, the formula for calculating the detonation load acting on the bottom of the perforated tubing string is as follows:

[0045]

[0046] Where, p k D is the pressure at the bottom of the well (the area at the bottom of the well). t d is the outer diameter of the perforated section of the tubing. t This refers to the inner diameter of the perforated section of the tubing.

[0047] As an optimization, the stress Q of the perforated tubing string is... M The calculation formula is:

[0048]

[0049] Among them, M j M is the bending moment acting on the tubing string. j =F c (d c -D t ) / 4;D t d is the outer diameter of the perforated section of the tubing. t This refers to the inner diameter of the perforated section of the tubing.

[0050] As an optimization, in S3, the specific steps for evaluating the safety of the tubing string based on the tubing string yield theory and calculating the safety factor of the tubing string are as follows:

[0051] S3.1 Determine whether the tubing string will buckle under impact load: If the detonation load at the bottom of the perforated tubing string is greater than the buckling critical load of the tubing string, the tubing string will buckle, and then jump to S3.2; otherwise, jump to S3.3.

[0052] S3.2 Determine the stress σ on the perforated tubing string. M The axial stress σ generated by the axial impact load on the tubing string N Is the sum less than the yield strength σ of the tubing string? S (The maximum stress that occurs when the tubing fails under external force can be measured experimentally.) If so, it means that although the tubing string has undergone spiral bending, it will not produce permanent deformation. Otherwise, it means that the tubing string will undergo irreversible permanent deformation.

[0053] S3.3 Calculate the safety factor of the tubing string:

[0054]

[0055] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0056] Compared to traditional methods for designing tubing strings for perforation acidizing tests in ultra-deep, small-bore gas wells, which do not consider the impact of perforation detonation on string strength, this invention proposes a safety performance evaluation method for oil tubing strings based on the perforation detonation effect. This method considers the impact of transient impact loads on string strength, making the design of oil and gas well tubing string structures more comprehensive and the safety performance considerations more complete. It provides scientific theoretical support for the optimization of ultra-deep well tubing string structures and the formulation of safety control measures for oil testing. Attached Figure Description

[0057] To more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of the present invention and should not be considered as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort. In the drawings:

[0058] Figure 1 A schematic diagram of the structure of an ultra-deep gas well.

[0059] Figure 2 This diagram shows the buckling instability, damage, and fracture of the tubing string in the perforated section under high-energy detonation load.

[0060] The attached diagram shows the markings and corresponding component names:

[0061] 1-Tubing, 2-Expansion joint, 3-APR testing tool, 4-Perforation gun, 5-TRRS packer, 6-Screen pipe, 7-Artificial well bottom. Detailed Implementation

[0062] 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 embodiments and accompanying drawings. The illustrative embodiments and descriptions of the present invention are only used to explain the present invention and are not intended to limit the present invention.

[0063] Example

[0064] Figure 1 This is a schematic diagram of the wellbore structure of an ultra-deep gas well. The present invention provides a method for assessing the safety performance of a tubing string based on the perforation detonation effect, comprising:

[0065] S1. Determine the influencing factors of the perforation detonation effect of the tubing string;

[0066] S2. Calculate the detonation effect parameters of the tubing string by identifying the influencing factors of the perforation detonation effect;

[0067] S3. By comparing the relevant parameters of the detonation effect, the safety of the tubing string is evaluated based on the tubing string yielding theory, and the safety factor of the tubing string is calculated.

[0068] In this embodiment, the factors influencing the perforation detonation effect include perforation projectile parameters, perforation parameters, perforation section casing parameters, perforation section tubing parameters, packer parameters, construction parameters, and reservoir parameters.

[0069] In this embodiment, wherein,

[0070] The parameters of the perforating projectile include: explosive type, charge mass (in g), and charge density (in g / m³).

[0071] The perforation parameters include: perforation density (in holes / m), perforation phase (in degrees), perforation diameter (in mm), perforation gun type, perforation top boundary (in m), and perforation bottom boundary (in m);

[0072] The parameters of the perforated section casing include: the outer diameter of the perforated section casing (in mm), the wall thickness of the perforated section casing (in mm), and the steel grade of the perforated section casing material;

[0073] The parameters of the perforated section tubing include: the outer diameter of the perforated section tubing (in mm), the wall thickness of the perforated section tubing (in mm), and the steel grade of the perforated section tubing material;

[0074] The packer parameters include: packer type, setting position (in meters), and tensile strength (in kN);

[0075] The construction parameters include: artificial well bottom (in meters), screen top boundary (in meters), screen bottom boundary (in meters), and perforation fluid density (in g / cm³). 3 ), location of shock absorbers (in meters) and number of shock absorbers (in units);

[0076] The reservoir parameters include: rock compressive strength (in MPa), elastic modulus (in MPa), Poisson's ratio, geostress, porosity (in %), and permeability (in mD).

[0077] In this embodiment, the detonation effect-related parameters include perforation detonation parameters, perforation detonation peak pressure, perforation pulsating pressure, detonation load acting on the bottom of the perforation tubing string, and stress on the perforation tubing string.

[0078] In this embodiment, the perforation detonation parameters include detonation heat, detonation temperature, detonation volume, detonation velocity, and detonation pressure, wherein,

[0079] The explosive Q jr The calculation formula is:

[0080] Q jr =Q 2-3 +ΔnRM;

[0081] Among them, Q 2-3 For isobaric detonation, Δn is the sum of the molar numbers of the gas components in the detonation products; R is the ideal gas constant; M is the relative molecular weight of the explosive.

[0082] The explosion temperature T jw The calculation formula is:

[0083] T jw =∑n i ΔE i ;

[0084] Where, n i For explosion product i, ΔE i The internal energy of the explosion product i;

[0085] The burst capacity V jv The calculation formula is:

[0086]

[0087] Among them, u i v is the number of moles of component i in the explosion product; j M is the number of moles of component j of the explosive; j is the molecular weight of component j of the explosive; m and n are the component numbers of the explosion products and the explosive, respectively.

[0088] The explosive speed Vj The calculation formula is:

[0089]

[0090] Among them, v max ρ is the detonation velocity at the theoretical density of the shaped charge, ρ0 is the actual charge density, and ρ max This is the theoretical density of the explosive (single-element explosive or mixed explosive);

[0091] The explosive pressure p Jv The calculation formula is:

[0092] p Jv =15.58(φ) e W) ρ 2 0;

[0093] Where, φ e φ represents the explosive component in the shaped charge mixture; W represents the mass fraction of the explosive component in the shaped charge mixture.

[0094] In this embodiment, the formula for calculating the peak pressure of the perforation detonation is:

[0095]

[0096] Where, p jy Pressure (explosive pressure); T jw V represents temperature (explosion temperature); n represents the number of perforation projectiles; V jv T is the volume (explosive capacity), n is the number of components in the explosive, and T is the explosive volume. b L represents the bottom hole temperature. j L is the length of the perforation section. d L is half the distance between the bottom of the perforated section and the bottom of the artificial well. s This refers to the length of the upper screen tube section.

[0097] In this embodiment, the formula for calculating the perforation pulsation pressure is:

[0098]

[0099] Where, p L Let p be the maximum pressure generated by bubble pulsation at a distance L from the burst point; L is the distance between the pressure point and the burst point. L should be greater than the critical burst depth, otherwise the calculation is meaningless. L <p max Only then does it have meaning, when p L >p max When taking p L =p max .

[0100] In this embodiment, the formula for calculating the detonation load acting on the bottom of the perforated tubing string is:

[0101]

[0102] Where, p k D is the pressure at the bottom of the well (the area at the bottom of the well). t d is the outer diameter of the perforated section of the tubing. t This refers to the inner diameter of the perforated section of the tubing.

[0103] In this embodiment, the stress σ on the perforated tubing string M The calculation formula is:

[0104]

[0105] Among them, M j M is the bending moment acting on the tubing string. j =F c (d c -D t ) / 4;D t d is the outer diameter of the perforated section of the tubing. t This refers to the inner diameter of the perforated section of the tubing.

[0106] In this embodiment, the specific steps in S3 for evaluating the safety of the tubing string based on the tubing string yield theory and calculating the safety factor of the tubing string are as follows:

[0107] S3.1 Determine whether the tubing string will buckle under impact load: If the detonation load at the bottom of the perforated tubing string is greater than the buckling critical load of the tubing string, the tubing string will buckle, and then jump to S3.2; otherwise, jump to S3.3.

[0108] S3.2 Determine the stress σ on the perforated tubing string. M The axial stress σ generated by the axial impact load on the tubing string N Is the sum less than the yield strength σ of the tubing string? S (The maximum stress that occurs when the tubing fails under external force can be measured experimentally.) If so, it means that although the tubing string has undergone spiral bending, it will not produce permanent deformation. Otherwise, it means that the tubing string will undergo irreversible permanent deformation.

[0109] S3.3 Calculate the safety factor of the tubing string:

[0110]

[0111] Next, the solution of the present invention will be described in further detail with reference to specific embodiments:

[0112] A certain well employed a combined perforation and acidizing test process, predicting a formation pressure coefficient of 1.76. The completed well depth was 5464m, with a predicted formation pressure of 80.02MPa and a density of 2.07g / cm³. 3 Gas intrusion was observed when drilling fluid reached the section from 4626.00 to 4646.00 m. The average porosity of the reservoir was 2.9%, and the average permeability was 0.285 mD. The packer was designed to be located at 4500 m, and the artificial bottom hole was at 4690 m. The tubing string was checked based on the perforation detonation effect to assess whether permanent deformation had occurred.

[0113] S1. Determine the influencing factors of the perforation detonation effect of the tubing string. The main influencing factors are explained in Appendix 1.

[0114] Table 1

[0115]

[0116]

[0117] S2. Calculate the detonation effect-related parameters of the tubing string based on the identified influencing factors of perforation detonation effect. Specifically:

[0118] ① Calculation of detonation parameters for perforation: The heat of explosion is calculated to be 1832.75 kJ / mol, the explosion temperature is 4816.0 K, and the explosion volume is 40.9 cm³. 3 The detonation velocity was 5.3 km / s, and the detonation pressure was 529.37 MPa.

[0119] ② Calculate the peak pressure of the perforation detonation: The peak pressure of the perforation detonation can be calculated to be 96.08 MPa;

[0120] ③ Calculate the perforation pulsation pressure: The pulsation pressure is calculated to be 71.13 MPa;

[0121] ④ Calculate the detonation load acting on the bottom of the perforated tubing string: The calculation shows that the detonation load at the bottom of the perforated tubing string is 396.08 MPa;

[0122] ⑤ Calculate the stress on the perforating string: The maximum stress on the perforating string can be calculated to be 645.61 MPa.

[0123] S3. By comparing the relevant parameters of the detonation effect, the safety of the tubing string is evaluated based on the tubing string yielding theory, and the safety factor of the tubing string is calculated.

[0124] Specifically, the criteria for assessing the safety of tubing based on tubing yield theory are as follows:

[0125] Determine σ M +σ N <σ s Is it true (σ)S (This is the yield strength of the tubing string). If it holds true, it means that although the tubing has undergone helical bending, it will not produce permanent deformation; if it does not hold true, it means that the tubing string will undergo irreversible permanent deformation.

[0126] Finally, the safety factor of the tubing string is determined based on the stress distribution. The calculated safety factor of the tubing string is 1.17. The safety factor threshold, i.e., the allowable safety factor, is then determined. The allowable safety factor is compared with the calculated safety factor to determine whether the calculated safety factor meets the strength requirements for perforation. If the allowable safety factor is less than the calculated safety factor, it indicates that the tubing string meets the strength requirements for perforation.

[0127] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for evaluating the safety performance of a tubing string based on the perforation detonation effect, characterized in that, include: S1. Determine the influencing factors of the perforation detonation effect of the tubing string; The factors influencing the perforation detonation effect include perforation projectile parameters, perforation parameters, perforation section casing parameters, perforation section tubing parameters, packer parameters, construction parameters, and reservoir parameters. S2. Calculate the detonation effect parameters of the tubing string by identifying the influencing factors of the perforation detonation effect; The detonation effect-related parameters include perforation detonation parameters, perforation detonation peak pressure, perforation pulsating pressure, detonation load acting on the bottom of the perforation tubing string, and stress on the perforation tubing string. S3. By comparing the relevant parameters of the detonation effect, the safety of the tubing string is evaluated based on the tubing string yielding theory, and the safety factor of the tubing string is calculated. The specific steps are as follows: S3.1 Determine whether the tubing string will buckle under impact load: If the detonation load at the bottom of the perforated tubing string is greater than the buckling critical load of the tubing string, the tubing string will buckle, and then jump to S3.2; otherwise, jump to S3.

3. S3.2 Determine the stress on the perforated tubing string Axial stress generated by axial impact load on the tubing string Is the sum less than the yield strength of the tubing string? , p k The pressure at the pocket indicates that although the tubing string has undergone spiral bending, it will not produce permanent deformation; otherwise, it indicates that the tubing string will undergo irreversible permanent deformation. S3.3 Calculate the safety factor of the tubing string: 。 2. The method for evaluating the safety performance of a tubing string based on the perforation detonation effect according to claim 1, characterized in that, in, The parameters of the perforating projectile include: explosive type, charge mass, and charge density; The perforation parameters include: perforation density, perforation phase, perforation diameter, perforation gun type, perforation top boundary, and perforation bottom boundary; The parameters of the perforated section casing include: the outer diameter of the perforated section casing, the wall thickness of the perforated section casing, and the steel grade of the perforated section casing. The parameters of the perforated section tubing include: the outer diameter of the perforated section tubing, the wall thickness of the perforated section tubing, and the steel grade of the perforated section tubing. The packer parameters include: packer type, setting position, and tensile strength; The construction parameters include: artificial well bottom, screen pipe top boundary, screen pipe bottom boundary, perforation fluid density, shock absorber location, and number of shock absorbers. The reservoir parameters include: rock compressive strength, elastic modulus, Poisson's ratio, geostress, porosity, and permeability.

3. The method for evaluating the safety performance of a tubing string based on the perforation detonation effect according to claim 1, characterized in that, The perforation detonation parameters include detonation heat, detonation temperature, detonation volume, detonation velocity, and detonation pressure, among which, The heat The calculation formula is: ； in, For isobaric detonation, Δn is the sum of the molar numbers of the gas components in the detonation products; R is the ideal gas constant; M is the relative molecular weight of the explosive. The explosion temperature The calculation formula is: ； in, For explosion product i, The internal energy of the explosion product i; The burst capacity The calculation formula is: ； Among them, u i v is the number of moles of component i in the explosion product; j M is the number of moles of component j of the explosive; j is the molecular weight of component j of the explosive; m and n are the component numbers of the explosion products and the explosive, respectively. Said explosion velocity The calculation formula is: ； in, The detonation velocity is the theoretical density of the shaped charge. This represents the actual density of the explosive charge. This is the theoretical density of the explosive; The explosive pressure The calculation formula is: ； in, For the explosive components in mixed shaped charge explosives value; It represents the mass fraction of the explosive component in a mixed shaped charge.

4. The method for evaluating the safety performance of a tubing string based on the perforation detonation effect according to claim 3, characterized in that, The formula for calculating the peak pressure of the perforation detonation is as follows: ； Where, p jy For burst pressure; T jw Explosion temperature; n is the number of perforation projectiles, V jv Let T be the explosive capacity, n be the number of components in the explosive, and T be the explosive volume. b L represents the bottom hole temperature. j L is the length of the perforation section. d L is half the distance between the bottom of the perforated section and the bottom of the artificial well. s This refers to the length of the upper screen tube section.

5. The method for evaluating the safety performance of a tubing string based on the perforation detonation effect according to claim 1, characterized in that, The formula for calculating the perforation pulsation pressure is as follows: ； Where, p L Let p be the maximum pressure generated by bubble pulsation at a distance L from the burst point; L is the distance between the pressure point and the burst point. L should be greater than the critical burst depth, otherwise the calculation is meaningless. L <p max Only then does it have meaning, when p L >p max When taking p L =p max .

6. The method for evaluating the safety performance of a tubing string based on the perforation detonation effect according to claim 1, characterized in that, The formula for calculating the detonation load acting on the bottom of the perforated tubing string is as follows: ； Where, p k For the pressure at the pocket, D t d is the outer diameter of the perforated section of the tubing. t This refers to the inner diameter of the perforated section of the tubing.

7. The method for evaluating the safety performance of a tubing string based on the perforation detonation effect according to claim 1, characterized in that, The stress on the perforated tubing string The calculation formula is: ； Among them, M j The bending moment experienced by the tubing string. ;D t d is the outer diameter of the perforated section of the tubing. t This refers to the inner diameter of the perforated section of the tubing.

Images