Acoustic property sensitivity analysis method and device for helium reservoir
By measuring and calculating the core elastic parameters of helium reservoirs, the problem of unclear acoustic response characteristics of helium reservoirs was solved, enabling effective exploration and identification of helium reservoirs.
Patent Information
- Application Number
- CN202411177496.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-08-26
- Publication Date
- 2026-03-03
AI Technical Summary
Existing technologies have failed to effectively determine the acoustic response characteristics of helium reservoirs, making helium reservoir exploration difficult.
By obtaining the core elastic parameters with different helium saturation and effective stress, the acoustic property sensitivity of helium reservoirs is analyzed. The bulk density, P-wave and S-wave velocities of the cores are measured using sonic logging methods, and Young's modulus, Poisson's ratio and bulk modulus are calculated to form a corresponding database.
This provides a solid foundation for the identification and evaluation of helium-rich reservoirs, and improves the exploration efficiency of helium reservoirs through acoustic property sensitivity analysis.
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Figure CN121595698A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of helium resource exploration technology, and in particular to a method and apparatus for acoustic property sensitivity analysis of helium reservoirs. Background Technology
[0002] Helium is an extremely light, colorless, odorless, and tasteless non-flammable gas at room temperature. It is chemically very stable and typically does not combine with other elements or compounds. Helium has a wide range of industrial applications and is an indispensable rare strategic material for cutting-edge technologies such as national defense, aerospace, atomic energy, low-temperature superconductivity, deep-sea diving, and lasers. Although helium accounts for 24% of the Milky Way galaxy, making it the second most abundant element in the universe after hydrogen, the amount of helium in the atmosphere is only about 0.00052%, a very low concentration. This makes helium extraction too costly and unsuitable for industrial use. Currently, industrial helium is mainly purified from natural gas.
[0003] Previous researchers have conducted in-depth studies on helium, a rare mineral resource. However, apart from well fluid sampling, there is still no research on how to use logging methods to explore helium reservoirs and what the logging response of helium reservoirs should be.
[0004] Sonic logging is one of the most commonly used methods in natural gas exploration. Therefore, in order to understand the acoustic response characteristics of helium, it is urgent to carry out research on the acoustic property sensitivity of helium reservoirs. Summary of the Invention
[0005] The purpose of this invention is to provide a method and apparatus for sensitivity analysis of the acoustic properties of helium reservoirs.
[0006] To achieve the above objectives, the present invention provides a method for acoustic property sensitivity analysis of helium reservoirs, comprising:
[0007] Obtain core elastic parameters with different helium saturation and effective stress;
[0008] Based on the core elastic parameters with different helium saturation and effective stress, the relationship between the core elastic parameters and helium saturation and effective stress was determined.
[0009] Based on the relationship between the elastic parameters of the core and helium saturation and effective stress, the acoustic property sensitivity of the helium reservoir is analyzed.
[0010] This invention also discloses an acoustic property sensitivity analysis device for helium reservoirs, comprising:
[0011] The acquisition unit is used to obtain the core elastic parameters under different helium saturation and effective stress.
[0012] The unit is defined to determine the relationship between the core elastic parameters and helium saturation and effective stress, respectively, based on the core elastic parameters under different helium saturation and effective stress.
[0013] The analysis unit is used to analyze the acoustic property sensitivity of helium reservoirs based on the relationship between the elastic parameters of the core and the helium saturation and effective stress.
[0014] The present invention also provides an electronic device, comprising: a processor coupled to a memory;
[0015] The processor is configured to read and execute a computer program stored in the memory to implement the method described in any of the preceding embodiments.
[0016] The present invention also provides a computer-readable storage medium storing a program or instructions that, when executed by a processor, implement the method as described in any of the preceding claims.
[0017] The technical effects and advantages of this invention are as follows:
[0018] This invention measures the acoustic properties (such as bulk density, P-wave velocity, and S-wave velocity) of core samples with different helium saturation levels, calculates the elastic parameters (such as Young's modulus, Poisson's ratio, and bulk modulus) of the core samples, examines the variation law of acoustic properties of core samples with different helium saturation levels, and then analyzes the acoustic property sensitivity of helium reservoirs to form a corresponding database, which can lay a solid foundation for the identification and evaluation of helium-rich reservoirs.
[0019] Other features and advantages of the invention will be set forth in the following description, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures pointed out in the description and the drawings. Attached Figure Description
[0020] Figure 1 Flowchart of the acoustic property sensitivity analysis method for helium reservoirs;
[0021] Figure 2 This is a schematic diagram of the volume model;
[0022] Figure 3 A schematic diagram of an improved acoustic wave measurement device;
[0023] Figure 4 The graph shows the variation of longitudinal wave velocity with different helium saturation levels.
[0024] Figure 5 This is a graph showing the variation of transverse wave velocity with different helium saturations.
[0025] Figure 6The graph shows the variation of Young's modulus with different helium saturation levels.
[0026] Figure 7 This is a graph showing the variation of Poisson's ratio with different helium saturation levels.
[0027] Figure 8 This is a graph showing the change in bulk modulus with different helium saturation levels. Detailed Implementation
[0028] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0029] It should be noted that the structures, proportions, sizes, etc., illustrated in the accompanying drawings are merely for illustrative purposes to aid those skilled in the art and to facilitate understanding and reading. They are not intended to limit the scope of the invention and therefore have no substantial technical significance. Any modifications to the structure, changes in proportions, or adjustments to size, without affecting the effectiveness and purpose of the invention, should still fall within the scope of the technical content disclosed herein. Furthermore, the terms "upper," "lower," "left," "right," "middle," and "one" used in this specification are merely for clarity and not intended to limit the scope of the invention. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of the invention.
[0030] To address the shortcomings of existing technologies, this invention discloses a method for sensitivity analysis of the acoustic properties of helium reservoirs, such as... Figure 1 As shown, the method includes:
[0031] 1. Obtain core elastic parameters with different helium saturation and effective stress.
[0032] Specifically, this includes: 1.1 Obtaining the bulk density of cores with different helium saturation levels.
[0033] The volumetric density of cores with different helium saturation levels is obtained by calculating the core skeleton density, helium density, and total core porosity obtained through measurement.
[0034] The formula for calculating the bulk density of cores with different helium saturation levels based on the volumetric model is as follows: Figure 2 As shown:
[0035] ρ b =(1-φ)ρ ma +φSg ρ He +φ(1-S g )ρ f
[0036] Among them, S g ρ represents the helium saturation level. f Let be the density of water. The bulk density is the mass per unit volume, typically used to describe the compaction of rock, and is denoted by ρb. The core skeleton density is the density inherent in the core itself, i.e., the ratio of the mass of the particles to the volume occupied by the skeleton entity, denoted by ρ. ma The helium density is expressed as ρ, which is closely related to pressure and temperature, decreasing with increasing temperature and increasing with increasing pressure. He The total porosity of the core is the ratio of the pore volume to the total volume of the core, usually represented by φ.
[0037] 1.2 Measurement of longitudinal and transverse wave velocities in cores with different helium saturation levels.
[0038] The core samples with different helium saturation levels are obtained by introducing helium into the core through a displacement system, forming core samples with different amounts of helium (i.e., the volume model above), with the aim of simulating the velocity changes of the core after the addition of helium.
[0039] The measurement of P-wave and S-wave velocities in core samples with different helium saturation levels was performed using a conventional acoustic measurement device with an added back pressure control module. The back pressure control module is a valve used to control the flow of liquids or gases; its function is to maintain a certain pressure in the measurement system to fully displace the fluid within the sample.
[0040] The conventional acoustic wave measuring device typically consists of three parts: a displacement system, a measuring system, and a metering system, such as... Figure 3 As shown, the details are as follows:
[0041] The displacement system applies pressure to allow fluid to enter the core, achieving a target state. This target state is a saturation level set by the researcher. Taking water saturation as an example, to study the physical properties of cores at different water saturation levels, the displacement system can be used to achieve water saturation levels of 10%, 20%, 30%, and 100%.
[0042] The measurement system measures the P-wave velocity and S-wave velocity of the rock core using experimental instruments. The P-wave velocity refers to the propagation speed of the P-wave, denoted by V. P The longitudinal wave is an elastic wave in which the vibration direction of the medium particles propagating it is the same as the wave's propagation direction. The transverse wave velocity refers to the propagation velocity of the transverse wave, denoted by V. SThis indicates that the transverse wave is an elastic wave in which the vibration direction of the medium particles propagating it is perpendicular to the wave propagation direction.
[0043] The metering system determines the saturation level of the core sample by measuring the volume of the displaced fluid using instruments such as measuring cups.
[0044] 1.3 Calculate the elastic parameters of cores with different helium saturation levels. That is, use the bulk density, P-wave velocity, and S-wave velocity to determine the Young's modulus, Poisson's ratio, bulk modulus, and other parameters of the cores.
[0045] The Young's modulus, which is the ratio of stress to strain, is a physical quantity describing the ability of a solid material to resist deformation. It is usually represented by E, and the specific calculation formula is as follows:
[0046]
[0047] Where E represents Young's modulus; ρ b V represents the bulk density of the rock core. P V represents the longitudinal wave velocity; S This indicates the velocity of the transverse wave.
[0048] Poisson's ratio is the ratio of lateral strain to axial strain in a rock under tension or compression. It is a parameter reflecting the lateral deformation of the rock and is usually represented by ν. The specific calculation formula is as follows:
[0049]
[0050] Where ν represents Poisson's ratio; V P V represents the longitudinal wave velocity; S This indicates the velocity of the transverse wave.
[0051] The bulk modulus is a physical quantity that reflects the relationship between the volumetric strain and the mean stress of a rock. It is used to reflect the macroscopic properties of the rock and is usually represented by K. The specific calculation formula is as follows:
[0052]
[0053] Where K represents the bulk modulus; E represents Young's modulus; and ν represents Poisson's ratio.
[0054] 2. Based on the core elastic parameters with different helium saturation and effective stress, determine the relationship between the core elastic parameters and helium saturation and effective stress.
[0055] 3. Based on the relationship between the elastic parameters of the core and the helium saturation and effective stress, analyze the acoustic property sensitivity of the helium reservoir.
[0056] By analyzing the variation patterns of parameters such as Young's modulus, Poisson's ratio, and bulk modulus with helium saturation, technical support is provided for the identification of helium-rich reservoirs. The specific analysis is as follows:
[0057] To better understand this solution, the following examples are provided.
[0058] A method for sensitivity analysis of the acoustic properties of helium reservoirs, specifically including:
[0059] 1. Obtain the bulk density of cores with different helium saturation levels.
[0060] The density of helium gas was measured under different effective stresses, with four effective stress conditions set at 20 MPa, 30 MPa, 40 MPa, and 50 MPa. The skeleton density and porosity of the core were measured, assuming the density of water to be 1 g / cm³. 3 The bulk density of core samples with different helium saturation levels can be calculated using the following formula:
[0061] ρ b =(1-φ)ρ ma +φS g ρ He +φ(1-S g )ρ f
[0062] Where, ρ b ρ represents the bulk density of the rock core. ma ρ represents the skeletal density of the rock core. He Indicates helium density; φ represents total core porosity; S g Indicates helium saturation; ρ f This indicates the density of water.
[0063] 2. Measure the longitudinal and transverse wave velocities of cores with different helium saturation levels.
[0064] The P-wave and S-wave velocities of core samples with different helium saturations were measured using an acoustic measurement device with an added back pressure control module. Five nodes were used for helium saturation: 0%, 31%, 53%, 72%, and 100%. Four nodes were used for effective stress conditions: 20 MPa, 30 MPa, 40 MPa, and 50 MPa. These were represented by squares, triangles, circles, and rhombuses, respectively. The measurement results are shown below. Figure 4 and 5 As shown. According to Figure 4 and 5It can be seen that as helium saturation increases, the P-wave velocity in the core gradually decreases. At an effective stress of 20 MPa, the P-wave velocity changes by 4.9% from 0% to 100% saturation. At the same saturation level, effective stress has little effect on P-wave velocity; at 31% helium saturation, the P-wave velocity changes by 1.2% from 20 MPa to 50 MPa. Similarly, as helium saturation increases, the S-wave velocity in the core gradually decreases. At an effective stress of 20 MPa, the S-wave velocity changes by 2.2% from 0% to 100% saturation. At the same saturation level, effective stress has little effect on S-wave velocity; at 31% helium saturation, the P-wave velocity changes by 1.9% from 20 MPa to 50 MPa. Therefore, neither helium saturation nor effective stress has a significant impact on P-wave or S-wave velocities.
[0065] 3. Calculate the elastic parameters of cores with different helium saturation levels.
[0066] Based on the results of steps 1 and 2, calculate Young's modulus, Poisson's ratio, and bulk modulus under different effective stresses and different helium saturations. The calculation results are as follows: Figure 6 , 7 As shown in Figure 8.
[0067] Figure 6 This is a graph showing the variation of Young's modulus with different helium saturation levels: the horizontal axis represents helium saturation, scaled from 0 to 100%; the vertical axis represents Young's modulus, in GPa, scaled from 50 to 60. Squares, triangles, circles, and rhombuses represent measurement states at effective stresses of 20 MPa, 30 MPa, 40 MPa, and 50 MPa, respectively. Five nodes are shown for helium saturation levels: 0%, 31%, 53%, 72%, and 100%. As helium saturation increases, the Young's modulus of the core gradually decreases. At an effective stress of 20 MPa, the rate of change of Young's modulus from 0% to 100% saturation is 7.8%. At the same saturation level, effective stress has little effect on Young's modulus; at a helium saturation of 31%, the rate of change of Young's modulus from 20 MPa to 50 MPa is 3.3%.
[0068] Figure 7This is a graph showing the variation of Poisson's ratio with different helium saturation levels: the horizontal axis represents helium saturation, scaled from 0 to 100%; the vertical axis represents Poisson's ratio, scaled from 0 to 0.4. Squares, triangles, circles, and rhombuses represent measurement conditions at effective stresses of 20 MPa, 30 MPa, 40 MPa, and 50 MPa, respectively. Five nodes are shown for helium saturation levels: 0%, 31%, 53%, 72%, and 100%. As helium saturation increases, the Poisson's ratio of the core gradually decreases. At an effective stress of 20 MPa, the rate of change of Poisson's ratio from 0% to 100% saturation is 12%. At the same saturation level, changes in effective stress have little effect on the Poisson's ratio; at a helium saturation of 31%, the rate of change of Poisson's ratio from 20 MPa to 50 MPa is 3.4%.
[0069] Figure 8 This is a graph showing the change in bulk modulus with different helium saturation levels: the horizontal axis represents helium saturation, scaled from 0 to 100%; the vertical axis represents bulk modulus, in GPa, scaled from 20 to 40. Squares, triangles, circles, and rhombuses represent measurement states at effective stresses of 20 MPa, 30 MPa, 40 MPa, and 50 MPa, respectively. Five nodes are shown for helium saturation levels: 0%, 31%, 53%, 72%, and 100%. As helium saturation increases, the core bulk modulus gradually decreases. At an effective stress of 20 MPa, the rate of change in bulk modulus from 0% to 100% saturation is 15.5%. At the same saturation level, changes in effective stress have little effect on the bulk modulus; at a helium saturation of 31%, the rate of change in Poisson's ratio from 20 MPa to 50 MPa is 1.1%.
[0070] The above analysis shows that, under the same conditions, the bulk modulus is the most sensitive to helium saturation, and therefore the bulk modulus can be selected as the preferred sensitive parameter for identifying helium reservoirs, followed by Poisson's ratio.
[0071] 4. Analysis of the sensitivity of acoustic properties of helium cores
[0072] The above experiments can be used to investigate the variation of helium core velocity and elastic parameters with effective stress and helium saturation, analyze the acoustic property sensitivity of helium cores, and form a corresponding database, which can lay a solid foundation for the identification and evaluation of helium-rich reservoirs. Analysis methods can include cross-plots, tables, etc., which will not be described in detail here; only cross-plots will be used as an example.
[0073] The present invention also provides an acoustic property sensitivity analysis device for helium reservoirs, comprising:
[0074] The acquisition unit is used to obtain the core elastic parameters under different helium saturation and effective stress.
[0075] The unit is defined to determine the relationship between the core elastic parameters and helium saturation and effective stress, respectively, based on the core elastic parameters under different helium saturation and effective stress.
[0076] The analysis unit is used to analyze the acoustic property sensitivity of helium reservoirs based on the relationship between the elastic parameters of the core and the helium saturation and effective stress.
[0077] The acquisition units include: a volume density acquisition unit, a longitudinal and transverse wave velocity acquisition unit, and an elastic parameter acquisition unit.
[0078] Specifically: the volumetric density acquisition unit includes a helium density acquisition module, a total porosity acquisition module, and a framework density acquisition module. The helium density acquisition module is used to measure the helium sample to obtain the helium density under different pressures; the total porosity acquisition module is used to measure the core sample to obtain the total porosity of the core sample; and the framework density acquisition module is used to measure the core sample to obtain the framework density of the core sample.
[0079] The P-wave and S-wave velocity acquisition unit is used to acquire the P-wave and S-wave velocities of core samples with different helium saturation levels.
[0080] The elastic parameter acquisition unit includes a Young's modulus acquisition module, a Poisson's ratio acquisition module, and a bulk modulus acquisition module. The Young's modulus acquisition module is used to acquire the Young's modulus of core samples with different helium saturation levels; the Poisson's ratio acquisition module is used to acquire the Poisson's ratio of core samples with different helium saturation levels; and the bulk modulus acquisition module is used to acquire the bulk modulus of core samples with different helium saturation levels.
[0081] Since the protection provided by this device is similar to that provided by the method described above, it will not be described in detail here. Please refer to the discussion section of the method described above for more information.
[0082] The present invention also provides a device. This electronic device includes: at least one processor, at least one communication interface, at least one memory, and at least one communication bus; optionally, the communication interface can be an interface of a communication module, such as an interface of a GSM module; the processor may be a CPU, an Application Specific Integrated Circuit (ASIC), or one or more integrated circuits configured to implement embodiments of the present invention. The memory may include high-speed RAM memory, and may also include non-volatile memory, such as at least one disk storage device. The memory stores a program, and the processor calls the program stored in the memory to execute the methods provided in the above embodiments of this application.
[0083] Corresponding to the methods described above in this application, this application also provides a computer storage medium. The computer storage medium stores a computer program, which is executed by a processor to perform the methods provided in the above embodiments of this application.
[0084] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.
Claims
1. A method for sensitivity analysis of the acoustic properties of a helium reservoir, characterized in that, include: Obtain core elastic parameters with different helium saturation and effective stress; Based on the core elastic parameters with different helium saturation and effective stress, the relationship between the core elastic parameters and helium saturation and effective stress was determined. Based on the relationship between the elastic parameters of the core and helium saturation and effective stress, the acoustic property sensitivity of the helium reservoir is analyzed.
2. The method according to claim 1, characterized in that, The acoustic properties parameters include: core bulk density, longitudinal wave velocity, and transverse wave velocity.
3. The method according to claim 2, characterized in that, The bulk density of the core under different helium saturation levels was calculated using the core skeleton density, helium density, and total core porosity.
4. The method according to claim 2, characterized in that, The bulk density of core samples at different helium saturations is calculated using the following formula: r b =(1-φ)ρ ma +φS g r He +φ(1-S g )r f Where, ρ b ρ represents the bulk density of the rock core. ma ρ represents the density of the core skeleton. He Indicates helium density; φ represents total core porosity; S g Indicates helium saturation; ρ f This indicates the density of water.
5. The method according to claim 2, characterized in that, The longitudinal and transverse wave velocities of core samples under different helium saturations were measured using an acoustic measurement device with an added back pressure control module.
6. The method according to claim 2, characterized in that, The core elastic parameters include at least one of the following: Young's modulus, Poisson's ratio, and bulk modulus.
7. The method according to claim 6, characterized in that, Young's modulus is calculated using the following formula: Where E represents Young's modulus; ρ b V represents the bulk density of the rock core. P V represents the longitudinal wave velocity; S This indicates the velocity of the transverse wave.
8. The method according to claim 6, characterized in that, Poisson's ratio is calculated using the following formula: Where ν represents Poisson's ratio; V P V represents the longitudinal wave velocity; S This indicates the velocity of the transverse wave.
9. The method according to claim 6, characterized in that, The bulk modulus is calculated using the following formula: Where K represents the bulk modulus; E represents Young's modulus; and ν represents Poisson's ratio.
10. A sensitivity analysis device for the acoustic properties of a helium reservoir, characterized in that, include: The acquisition unit is used to obtain the core elastic parameters under different helium saturation and effective stress. The unit is defined to determine the relationship between the core elastic parameters and helium saturation and effective stress, respectively, based on the core elastic parameters under different helium saturation and effective stress. The analysis unit is used to analyze the acoustic property sensitivity of helium reservoirs based on the relationship between the elastic parameters of the core and the helium saturation and effective stress.
11. An electronic device, characterized in that, include: Processor, the processor being coupled to memory; The processor is configured to read and execute a computer program stored in the memory to implement the method as described in any one of claims 1-9.
12. A computer-readable storage medium storing a program or instructions, characterized in that, When the program or instructions are executed by the processor, they implement the method as described in any one of claims 1-9.