High-pressure water jet pressure relief and anti-reflection effect studying and judging method based on silica gel complex mold inversion

Abstract

According to the high-pressure water jet pressure relief and permeability improvement effect studying and judging method based on silica gel complex model inversion, the quantitative characterization relation between the hole volume and the pressure relief and permeability improvement effect is established by reconstructing the shape of a hole and accurately inverting the hole volume parameter of jet pore forming, and meanwhile the pressure relief and permeability improvement effect of the high-pressure water jet is researched and judged based on a high-pressure water jet experiment. And a quantitative relation of each jet parameter to the hole volume is established, and reliable technical support is provided for jet parameter optimization, gas extraction efficiency improvement and engineering safety guarantee in engineering field application.

Description

Technical Field

[0001] This invention belongs to the field of safe and efficient mining development, and specifically relates to a method for judging the pressure relief and permeability enhancement effect of high-pressure water jet based on silicone model inversion. Background Technology

[0002] As coal mining extends to deeper layers, high ground stress, high ground temperature, high gas pressure, and low porosity severely restrict the management of gas hazards and the safe mining of resources in deep coal seams. High-pressure water jet decompression and permeability enhancement technology has become one of the main methods for deep coal seam gas control due to its high coal breaking efficiency and significant decompression effect. The volume of the pores formed by the jet is a key indicator for measuring the decompression and permeability enhancement effect. The change in pore volume is affected by key parameters of the water jet, and in-depth research on the relationship among these three factors is of great significance for optimizing hydraulic coal seam gas control technology. However, existing research methods face technical challenges such as the difficulty in accurately quantifying the three-dimensional morphology of pores formed by jet impact crushing of coal, making it difficult to determine the effective range of decompression and permeability enhancement, and leaving the results of permeability enhancement uncertain.

[0003] In high-pressure water jet perforation experiments and industrial field experiments, numerical analysis techniques are often used to determine the morphology of the jet perforation. However, this technique suffers from problems such as model simplification, large deviations from actual working conditions, limitations in the scale and time scale of numerical calculations, and simplification of jet-solid coupling details. In addition, the analysis is constrained by the physical simulation environment, making it difficult to fully reproduce the "three highs and one low" geological conditions of deep coal seams and complete dynamic perforation morphology information. As a result, the above techniques cannot accurately quantify the jet perforation volume parameters, leading to a lack of correlation between water jet parameters and pressure relief and permeability enhancement effects. This restricts the optimization of jet parameters and hinders the improvement of the efficiency of high-pressure water jet pressure relief and permeability enhancement technology and its practical application path. Summary of the Invention

[0004] To address the technical problems existing in the prior art, this invention proposes a method for evaluating the pressure relief and permeability enhancement effect of high-pressure water jet based on silicone composite model inversion. By reconstructing the pore morphology, the method accurately inverts the pore volume parameters of the jet formation, establishes a quantitative characterization relationship between pore volume and pressure relief and permeability enhancement effect, and establishes a quantitative relationship between various jet parameters and pore volume based on high-pressure water jet experiments. This provides reliable technical support for optimizing jet parameters, improving gas extraction efficiency, and ensuring engineering safety in engineering field applications.

[0005] A method for evaluating the pressure relief and permeation enhancement effect of high-pressure water jet based on silicone mold inversion includes,

[0006] Establish a quantitative characterization relationship between pore volume and pressure relief / permeability enhancement effect: β = μ·V λ (λ>0), β represents the pressure relief and penetration enhancement effect, V represents the jet orifice volume, μ is the proportionality coefficient, which represents the pressure relief and penetration enhancement effect that a unit volume of jet orifice can bring under linear conditions, and λ is used to quantitatively represent the exponential relationship between the pressure relief and penetration enhancement effect and the orifice volume.

[0007] Based on high-pressure water jet experiments, a quantitative relationship was established between the volume of the cavity formed by the jet impact and various jet parameters. Where a, b, m, and n quantitatively represent the jet pressure P. jp Target distance D, punching time t, confining pressure P cp The exponential relationship between the volume of the pore and the volume of the hole;

[0008] The volume of the jet cavity was determined using a silicone casting cavity replication method, and the mass (m) of the jet cavity replication colloid was measured. colloid and density ρ colloid Calculate the volume V of the silicone colloid. colloid The volume V of the cavity formed by the water jet impact is inverted, where V = V colloid ;

[0009] Based on the high-pressure water jet perforation experiment, at the preset jet pressure P jp Target distance D, punching time t, confining pressure P cp The corresponding numerical values ​​of the pore volume are obtained below. Through experimental data, the universal quantitative relationship between each parameter and the pore volume is obtained, that is, the values ​​of a, b, m, and n are determined.

[0010] Establish the relationship between pressure relief and penetration enhancement effect β and jet pressure P jp Target distance D, punching time t, confining pressure P cp Quantitative relationship between them: The pressure relief and permeability enhancement effect β is represented by the change in the increase in coal seam gas drainage, the increase in gas extraction concentration, or the decrease in gas concentration in the mining space before and after pressure relief and permeability enhancement. Based on high-pressure water jet perforation experimental data, the values ​​of μ and λ are calculated, thus clarifying the relationship between the pressure relief and permeability enhancement effect β and the jet pressure P. jp Target distance D, time t, confining pressure P cp The quantitative relationship between them.

[0011] Furthermore, the samples used in the high-pressure water jet experiment were similar material samples prepared based on the mechanical property parameters of coal seams in industrial sites, and high-pressure water jet perforation experiments were carried out under different jet parameter conditions.

[0012] Furthermore, the mechanical properties of coal seams include compressive strength σ. c Tensile strength σ t Elastic modulus E, internal friction angle Cohesion c, Poisson's ratio υ.

[0013] Furthermore, the jet orifice volume was determined using a silicone casting orifice replication method, and also included...

[0014] After the high-pressure water jet hole-forming experiment, AB two-component silicone was selected as the molding material. Component A, which is the base adhesive, is a low-viscosity liquid at room temperature with good fluidity, and component B is the curing agent.

[0015] Mix components A and B in a 1:1 volume ratio and stir until the mixture does not separate into layers. Transfer the mixture into a vacuum degassing instrument and continue degassing until no more bubbles are released from the colloid.

[0016] The degassed colloid is delivered to the water jet orifice, and the flow rate is controlled to be delivered at a low and stable speed to avoid air bubbles being trapped due to excessive flow rate. Low-frequency vibration is carried out while pouring, and the pouring is completed in 2-3 times to avoid air bubble residue.

[0017] After pouring, allow the mixed silicone to stand for more than 24 hours to ensure that the mixed liquid is completely cured to form a highly elastic, low-shrinkage colloid. Slowly separate the colloid to ensure the integrity of the molded body.

[0018] Determining the mass m of the colloid in the cavity replica colloid and density ρ colloid Calculate the volume V of the silicone colloid. colloid The volume V of the cavity formed by the water jet impact is inverted, where V = V colloid .

[0019] The method for evaluating the pressure relief and permeability enhancement effect of high-pressure water jet based on silicone mold inversion of the present invention is applicable to engineering sites. It involves preparing similar material samples based on the mechanical characteristics of coal seams and setting different jet pressures (P). jp ), target distance (D) and punching time (t), confining pressure (P) cp High-pressure water jet perforation experiments were conducted. Based on silicone molding technology, the pore volume was accurately inverted, and a quantitative relationship was established between the pressure relief and permeability enhancement effect β and various key jet parameters. This quantitative relationship can be used to determine the effects of different jets and environmental parameters (jet pressure P). jp Target distance D, time t, confining pressure P cp The jet pressure, target distance, and time can be dynamically adjusted according to the coal seam conditions (confining pressure) to achieve the optimal pressure relief and permeability enhancement effect, providing data support for improving gas extraction efficiency.

[0020] Meanwhile, based on silicone molding technology, this invention accurately restores the internal morphology of jet pores and inverts the pore volume through the synergistic effect of vacuum degassing and vibration compaction. By preparing coal-like material samples, high-pressure water jet perforation experiments under different parameters are conducted, providing data support for establishing a quantitative relationship between the pressure relief and permeability enhancement effect β and various parameters. Furthermore, by establishing the relationship between the pressure relief and permeability enhancement effect β and various jet parameters (jet pressure P), this invention provides further data support for establishing a quantitative relationship between the pressure relief and permeability enhancement effect β and various jet parameters (jet pressure P). jp Target distance D, time t, confining pressure P cp Relationship between ) This provides a basis for optimizing key parameters of high-pressure water jet depressurization and permeability enhancement. Detailed Implementation

[0021] To address the technical problems existing in the prior art, this invention proposes a method for evaluating the pressure relief and permeability enhancement effect of high-pressure water jet based on silicone composite model inversion. By reconstructing the pore morphology, the method accurately inverts the pore volume parameters of the jet formation, establishes a quantitative characterization relationship between pore volume and pressure relief and permeability enhancement effect, and establishes a quantitative relationship between various jet parameters and pore volume based on high-pressure water jet experiments. This provides reliable technical support for optimizing jet parameters, improving gas extraction efficiency, and ensuring engineering safety in engineering field applications.

[0022] A method for evaluating the pressure relief and permeation enhancement effect of high-pressure water jet based on silicone mold inversion includes,

[0023] Establish a quantitative characterization relationship between pore volume and pressure relief / permeability enhancement effect: β = μ·V λ (λ>0), β represents the pressure relief and penetration enhancement effect, V represents the jet orifice volume, μ is the proportionality coefficient, which represents the pressure relief and penetration enhancement effect that a unit volume of jet orifice can bring under linear conditions, and λ is used to quantitatively represent the exponential relationship between the pressure relief and penetration enhancement effect and the orifice volume.

[0024] Based on high-pressure water jet experiments, a quantitative relationship was established between the volume of the cavity formed by the jet impact and various jet parameters. Where a, b, m, and n quantitatively represent the jet pressure P. jp Target distance D, punching time t, confining pressure P cp The exponential relationship between the volume of the pore and the volume of the hole;

[0025] The volume of the jet cavity was determined using a silicone casting cavity replication method, and the mass (m) of the jet cavity replication colloid was measured. colloid and density ρ colloid Calculate the volume V of the silicone colloid. colloid The volume V of the cavity formed by the water jet impact is inverted, where V = V colloid ;

[0026] Based on the high-pressure water jet perforation experiment, at the preset jet pressure P jp Target distance D, punching time t, confining pressure P cp The corresponding numerical values ​​of the pore volume are obtained below. Through experimental data, the universal quantitative relationship between each parameter and the pore volume is obtained, that is, the values ​​of a, b, m, and n are determined.

[0027] Establish the relationship between pressure relief and penetration enhancement effect β and jet pressure P jp Target distance D, punching time t, confining pressure P cp Quantitative relationship between them: The pressure relief and permeability enhancement effect β is represented by the change in the increase in coal seam gas drainage, the increase in gas extraction concentration, or the decrease in gas concentration in the mining space before and after pressure relief and permeability enhancement. Based on high-pressure water jet perforation experimental data, the values ​​of μ and λ are calculated, thus clarifying the relationship between the pressure relief and permeability enhancement effect β and the jet pressure P. jp Target distance D, time t, confining pressure P cp The quantitative relationship between them.

[0028] Furthermore, the samples used in the high-pressure water jet experiment were similar material samples prepared based on the mechanical property parameters of coal seams in industrial sites, and high-pressure water jet perforation experiments were carried out under different jet parameter conditions.

[0029] High-pressure water jet perforation experiments are usually conducted in the laboratory instead of industrial field tests to overcome the limitations of field equipment and construction environment. However, raw coal samples from deep coal seams are difficult to meet the requirements of water jet perforation experiments in terms of integrity, size and ease of preparation. Therefore, this invention uses similar material samples with the same mechanical properties as those of coal seams in industrial field tests. This method is convenient to operate and can significantly improve the repeatability and accuracy of the experiment.

[0030] Furthermore, the mechanical properties of coal seams include compressive strength σ. c Tensile strength σ t Elastic modulus E, internal friction angle Cohesion c, Poisson's ratio υ.

[0031] Furthermore, the jet orifice volume was determined using a silicone casting orifice replication method, and also included...

[0032] After the high-pressure water jet hole-forming experiment, AB two-component silicone was selected as the molding material. Component A, which is the base adhesive, is a low-viscosity liquid at room temperature with good fluidity, and component B is the curing agent.

[0033] Mix components A and B in a 1:1 volume ratio and stir until the mixture does not separate into layers. Transfer the mixture into a vacuum degassing instrument and continue degassing until no more bubbles are released from the colloid.

[0034] The degassed colloid is delivered to the water jet orifice, and the flow rate is controlled to be delivered at a low and stable speed to avoid air bubbles being trapped due to excessive flow rate. Low-frequency vibration is carried out while pouring, and the pouring is completed in 2-3 times to avoid air bubble residue.

[0035] After pouring, allow the mixed silicone to stand for more than 24 hours to ensure that the mixed liquid is completely cured to form a highly elastic, low-shrinkage colloid. Slowly separate the colloid to ensure the integrity of the molded body.

[0036] Determining the mass m of the colloid in the cavity replica colloid and density ρcolloid Calculate the volume V of the silicone colloid. colloid The volume V of the cavity formed by the water jet impact is inverted, where V = V colloid .

[0037] In on-site engineering tests, the irregularity of pores formed by impact under different parameters makes it difficult to efficiently, accurately, and cost-effectively determine the pore volume, thus obscuring the quantitative relationship between the pressure relief and permeability enhancement effect and the volume parameters. The use of silicone molding technology can accurately measure the pore volume, providing data support for determining parameter values.

[0038] In a specific embodiment, the volume of the cavity formed by the jet impact has the following relationship with each jet parameter.

[0039] Increased jet pressure enhances the jet energy acting on the coal body, promoting the growth of pore volume V. This relationship can be expressed as: Increased confining pressure inhibits jet pore development, leading to a decrease in pore volume parameters. This relationship can be expressed as follows: When 0 < D < D x Since the jet energy accumulation is insufficient, the volume change can be ignored, i.e., V1≈0 is set at this point, and the target distance is within the effective impact range D. x ≤D≤D y The time has a significant impact on the change of volume parameters, and the volume parameter V increases exponentially. Let the volume of the hole at this time be V2, and the relationship can be expressed as: V2∝D b (b>0), when D>D y At this point, the jet diverges during transmission, greatly weakening the jet energy, and the increase in volume parameters can also be ignored, i.e., V3≈V2. In summary, the relationship between target distance and volume can be expressed as:

[0040] V∝D b ,b>0(D x ≤D≤D y )

[0041] (where D is in the formula) x D y This only represents the critical value for distinguishing the effective impact range of the target distance; according to the segmented definition of the target distance, b represents the exponential relationship between the target distance and the cavity volume within the effective impact range.

[0042] As the punching time increases, the jet energy acting on the coal increases, promoting volume growth. When 0 < t ≤ t z The volume parameter of the pore increases significantly over time, and the relationship can be expressed as: V∝t m (m>0), but when t>t z At that time, due to the weakening effect of jet flooding on the coal body, the growth of the pore volume slows down and can be ignored. Therefore, the relationship between time and volume can be expressed as follows:

[0043] V∝t m m>0 (0<t≤t) z )

[0044] (where t is in the formula) z This only represents the critical value for distinguishing time ranges; according to the definition of time segmentation, m quantitatively represents the exponential relationship between time and pore volume within the effective operating time.

[0045] Furthermore, based on the high-pressure water jet perforation experiment, at a preset jet pressure P jp Target distance D, punching time t, confining pressure P cp The corresponding numerical values ​​of the pore volume are obtained below. Through experimental data, the universal quantitative relationship between each parameter and the pore volume is obtained, that is, the values ​​of a, b, m, and n are determined.

[0046] In a specific high-pressure water jet perforation experiment, the jet pressure P is kept constant. jp For quantitative conditions, at different target distances (D1, D2, D3...D... n A punching experiment was conducted at a specific target distance D. The results were recorded. i Under different confining pressures, different confining pressures were carried out respectively. Impact at different times (t1, t2, t3...t) n The value of the orifice volume V; changing the jet pressure to different values. Repeat the above method to record the orifice volume V under different jet pressures. Based on the recorded data, the values ​​of the corresponding parameters can be calculated. Following the above method, record multiple different parameters (jet pressure P). jp Target distance D, time t, confining pressure P cp The combined water jet impact forms the cavity volume V. The values ​​of a, b, m, and n are fitted by software. When there is more effective experimental data, regression analysis can more accurately fit the values ​​of parameters a, b, m, and n. The regression analysis uses existing mathematical calculation methods, which will not be elaborated here.

[0047] Furthermore, the pressure relief and penetration enhancement effect (β) was established in relation to various parameters (jet pressure P). jp Target distance D, time t, confining pressure P cp Quantitative relationship between them: For example, the increase in coal seam gas extraction and emission ΔQ before and after jet perforation can be used to characterize the pressure relief and permeability enhancement effect β. Simultaneously, the orifice volume V can be measured. By measuring multiple sets of experimental data (ΔQ and V), the values ​​of μ and λ can be calculated comprehensively, clarifying the relationship between the pressure relief and permeability enhancement effect β and various jet parameters (jet pressure P). jp Target distance D, time t, confining pressure P cp The quantitative relationship between them.

[0048] In a specific high-pressure water jet perforation experiment, the jet pressure P is kept constant. jp For quantitative conditions, at different target distances (D1, D2, D3...D... n Punching experiments were conducted under the same target distance D and different confining pressures. Impact at different times (t1, t2, t3...t) n The value of ΔQ is recorded at different jet pressures using the method described above. The values ​​of ΔQ are then determined. Substituting the values ​​of a, b, m, and n obtained from the above calculations with the recorded experimental data, the values ​​of μ and λ are obtained through fitting.

[0049] The method for evaluating the pressure relief and permeability enhancement effect of high-pressure water jet based on silicone mold inversion of the present invention is applicable to engineering sites. It involves preparing similar material samples based on the mechanical characteristics of coal seams and setting different jet pressures (P). jp ), target distance (D) and punching time (t), confining pressure (P) cp High-pressure water jet perforation experiments were conducted. Based on silicone molding technology, the pore volume was accurately inverted, and a quantitative relationship was established between the pressure relief and permeability enhancement effect β and various key jet parameters. This quantitative relationship can be used to determine the effects of different jets and environmental parameters (jet pressure P). jp Target distance D, time t, confining pressure P cp The jet pressure, target distance, and time can be dynamically adjusted according to the coal seam conditions (confining pressure) to achieve the optimal pressure relief and permeability enhancement effect, providing data support for improving gas extraction efficiency.

[0050] Meanwhile, based on silicone molding technology, this invention accurately restores the internal morphology of jet pores and inverts the pore volume through the synergistic effect of vacuum degassing and vibration compaction. By preparing coal-like material samples, high-pressure water jet perforation experiments under different parameters are conducted, providing data support for establishing a quantitative relationship between the pressure relief and permeability enhancement effect β and various parameters. Furthermore, by establishing the relationship between the pressure relief and permeability enhancement effect β and various jet parameters (jet pressure P), this invention provides further data support for establishing a quantitative relationship between the pressure relief and permeability enhancement effect β and various jet parameters (jet pressure P). jp Target distance D, time t, confining pressure P cp Relationship between ) This provides a basis for optimizing key parameters of high-pressure water jet depressurization and permeability enhancement.

[0051] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for evaluating the pressure relief and permeability enhancement effect of high-pressure water jet based on silicone mold inversion, characterized in that, include, Establish a quantitative characterization relationship between pore volume and pressure relief / permeability enhancement effect: β = μ·V λ (λ>0), β represents the pressure relief and penetration enhancement effect, V represents the jet orifice volume, μ is the proportionality coefficient, which represents the pressure relief and penetration enhancement effect that a unit volume of jet orifice can bring under linear conditions, and λ is used to quantitatively represent the exponential relationship between the pressure relief and penetration enhancement effect and the orifice volume. Based on high-pressure water jet experiments, a quantitative relationship was established between the volume of the cavity formed by the jet impact and various jet parameters. Where a, b, m, and n quantitatively represent the jet pressure P. jp Target distance D, punching time t, confining pressure P cp The exponential relationship between the volume of the pore and the volume of the hole; The volume of the jet cavity was determined using a silicone casting cavity replication method, and the mass (m) of the jet cavity replication colloid was measured. colloid and density ρ colloid Calculate the volume V of the silicone colloid. colloid The volume V of the cavity formed by the water jet impact is inverted, where V = V colloid ; Based on the high-pressure water jet perforation experiment, at the preset jet pressure P jp Target distance D, punching time t, confining pressure P cp The corresponding numerical values ​​of the pore volume are obtained below. Through experimental data, the universal quantitative relationship between each parameter and the pore volume is obtained, that is, the values ​​of a, b, m, and n are determined. Establish the relationship between pressure relief and penetration enhancement effect β and jet pressure P jp Target distance D, punching time t, confining pressure P cp Quantitative relationship between them: The pressure relief and permeability enhancement effect β is represented by the change in the increase in coal seam gas drainage, the increase in gas extraction concentration, or the decrease in gas concentration in the mining space before and after pressure relief and permeability enhancement. Based on high-pressure water jet perforation experimental data, the values ​​of μ and λ are calculated, thus clarifying the relationship between the pressure relief and permeability enhancement effect β and the jet pressure P. jp Target distance D, time t, confining pressure P cp The quantitative relationship between them.

2. The method for evaluating the pressure relief and permeability enhancement effect of high-pressure water jet based on silicone mold inversion according to claim 1, characterized in that, The samples used in the high-pressure water jet experiment are similar material samples with the same mechanical properties as the coal seam prepared based on the mechanical properties of the coal seam in the industrial field, so as to carry out high-pressure water jet perforation experiments under different jet parameter conditions.

3. The method for evaluating the pressure relief and permeability enhancement effect of high-pressure water jet based on silicone mold inversion according to claim 2, characterized in that, The mechanical properties of coal seams include compressive strength σ. c Tensile strength σ t Elastic modulus E, internal friction angle Cohesion c, Poisson's ratio υ.

4. A method for evaluating the pressure relief and penetration enhancement effect of high-pressure water jet based on silicone replica inversion according to claim 1 or 3, characterized in that, The volume of the jet orifice was determined using a silicone casting orifice replication method, and also included... After the high-pressure water jet hole-forming experiment, AB two-component silicone was selected as the molding material. Component A, which is the base adhesive, is a low-viscosity liquid at room temperature with good fluidity, and component B is the curing agent. Mix components A and B in a 1:1 volume ratio and stir until the mixture does not separate into layers. Transfer the mixture into a vacuum degassing instrument and continue degassing until no more bubbles are released from the colloid. The degassed colloid is delivered to the water jet orifice, and the flow rate is controlled to be delivered at a low and stable speed to avoid air bubbles being trapped due to excessive flow rate. Low-frequency vibration is carried out while pouring, and the pouring is completed in 2-3 times to avoid air bubble residue. After pouring, allow the mixed silicone to stand for more than 24 hours to ensure that the mixed liquid is completely cured to form a highly elastic, low-shrinkage colloid. Slowly separate the colloid to ensure the integrity of the molded body. Determining the mass m of the colloid in the cavity replica colloid and density ρ colloid Calculate the volume V of the silicone colloid. colloid The volume V of the cavity formed by the water jet impact is inverted, where V = V colloid .

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