阅读说明：本技术 岩石模量测量系统及方法 (Rock modulus measuring system and method ) 是由 曹宏 杨志芳 于 2020-06-04 设计创作，主要内容包括：本发明公开了一种岩石模量测量系统及方法,其中,该系统包括：承样模块：用于放置岩石样品；压力控制模块：用于向岩石样品施加预设压力,静态模量测量模块：用于采集岩石样品在施加预设压力前后的应力,确定岩石样品的静态杨氏模量和静态泊松比；低频动态模量测量模块：用于在预设压力下,确定岩石模型的低频动态杨氏模量和低频动态泊松比,高频动态模量测量模块：用于在预设压力下,确定岩石样品的高频动态杨氏模量和高频动态泊松比,本发明可以实现同一岩石样品在相同的环境条件下进行动态岩石模量测量和静态岩石模量测量,测量结果的可对比性强。(The invention discloses a rock modulus measuring system and a method, wherein the system comprises: a sample bearing module: for placing a rock sample; a pressure control module: for applying a preset pressure to the rock sample, a static modulus measurement module: the method is used for collecting stress of a rock sample before and after a preset pressure is applied, and determining the static Young modulus and the static Poisson ratio of the rock sample; the low-frequency dynamic modulus measuring module comprises: the device comprises a high-frequency dynamic modulus measuring module, a low-frequency dynamic Young modulus measuring module and a low-frequency dynamic Poisson ratio measuring module, wherein the low-frequency dynamic Young modulus and the low-frequency dynamic Poisson ratio of a rock model are determined under preset pressure: the method is used for determining the high-frequency dynamic Young modulus and the high-frequency dynamic Poisson ratio of the rock sample under the preset pressure, the dynamic rock modulus measurement and the static rock modulus measurement of the same rock sample can be realized under the same environmental condition, and the contrast of the measurement result is strong.)

1. A rock modulus measurement system, comprising: the device comprises a sample bearing module, a pressure control module, a static modulus measuring module, a low-frequency dynamic modulus measuring module and a high-frequency dynamic modulus measuring module;

the sample bearing module is used for placing a rock sample;

the pressure control module is used for applying preset pressure to the rock sample;

the static modulus measurement module is configured to: collecting stress of a rock sample before and after applying a preset pressure; determining the static Young modulus and the static Poisson ratio of the rock sample according to the stress of the rock sample before and after the preset pressure is applied;

the low-frequency dynamic modulus measuring module is used for: applying vibration forces of different frequencies to the rock sample at the preset pressure, wherein the frequency of the vibration forces is lower than a preset frequency threshold; collecting stress changes of the rock sample under different frequency vibration forces; determining the low-frequency dynamic Young modulus and the low-frequency dynamic Poisson ratio of the rock model according to the stress change;

the high-frequency dynamic modulus measuring module is used for: emitting ultrasonic waves to the rock sample under the preset pressure, wherein the frequency of the ultrasonic waves is higher than a preset frequency threshold value; receiving ultrasonic waves after passing through the rock model; and determining the high-frequency dynamic Young modulus and the high-frequency dynamic Poisson's ratio of the rock sample according to the ultrasonic wave after passing through the rock model.

2. The system of claim 1, wherein the sample support module comprises: the rock sample is fixed between the upper cushion block and the lower cushion block through the locking ring.

3. The system of claim 1, wherein the static modulus measurement module comprises:

the strain gauge is used for outputting an electric signal of stress change of the rock sample before and after a preset pressure is applied;

the resistance meter is used for determining the stress of the rock sample before and after the preset pressure is applied according to the electric signal of the stress change;

and the static modulus determining unit is used for determining the static Young modulus and the static Poisson ratio of the rock sample according to the stress of the rock sample before and after the preset pressure is applied.

4. The system of claim 3, wherein the strain gage is affixed to a surface of the rock sample.

5. The system of claim 4, wherein the strain gage and the rock sample are sealed by a sealant sleeve.

6. The system of claim 1, wherein the low frequency dynamic modulus measurement module comprises:

the vibration exciter is used for applying vibration forces with different frequencies to the rock sample under the preset pressure;

the strain gauge is used for outputting an electric signal of stress change of the rock sample under different frequency vibration forces;

the stress change measuring unit is used for determining the change of the voltage amplitude according to the stress change electric signal; determining the stress change of the rock sample under different frequency vibration forces according to the change of the voltage amplitude value;

and the low-frequency dynamic modulus determining unit is used for determining the low-frequency dynamic Young modulus and the low-frequency dynamic Poisson ratio of the rock model according to the stress change of the rock sample under different frequency vibration forces.

7. The system of claim 1, wherein the high frequency dynamic modulus measurement module comprises:

the ultrasonic transmitter is used for transmitting ultrasonic waves to the rock sample under the preset pressure;

an ultrasonic receiver for receiving ultrasonic waves after passing through the rock sample;

the high-frequency dynamic modulus determining unit is used for determining the propagation speed of the ultrasonic wave in the rock sample according to the ultrasonic wave after the ultrasonic wave passes through the rock sample; and determining the high-frequency dynamic Young modulus and the high-frequency dynamic Poisson's ratio of the rock sample according to the propagation velocity.

8. The system of claim 1, wherein: the sample bearing module comprises: the pressure kettle is used for accommodating the rock sample;

the pressure control module includes:

the axial pressure control unit is used for injecting gas into the pressure kettle through a digital pump and an axial pressure pipeline and controlling the axial pressure applied to the rock sample;

and the confining pressure control unit is used for injecting fluid into the pressure kettle through a digital pump and a confining pressure pipeline and controlling the magnitude of confining pressure applied to the rock sample.

9. The system of claim 8, wherein the pressure control module is further to: and controlling the rock sample to be at a preset temperature.

10. The system of claim 8, wherein the pressure control module is further to: the rock sample is controlled at a preset fluid saturation.

11. A rock modulus measuring method applied to the system of any one of claims 1 to 10, comprising:

applying a preset pressure to the rock sample;

collecting stress of a rock sample before and after applying a preset pressure; determining the static Young modulus and the static Poisson ratio of the rock sample according to the stress of the rock sample before and after the preset pressure is applied;

applying vibration forces of different frequencies to the rock sample at the preset pressure, wherein the frequency of the vibration forces is lower than a preset frequency threshold; collecting stress changes of the rock sample under different frequency vibration forces; determining the low-frequency dynamic Young modulus and the low-frequency dynamic Poisson ratio of the rock model according to the stress change;

emitting ultrasonic waves to the rock sample under the preset pressure, wherein the frequency of the ultrasonic waves is higher than a preset frequency threshold value; receiving ultrasonic waves after passing through the rock model; and determining the high-frequency dynamic Young modulus and the high-frequency dynamic Poisson's ratio of the rock sample according to the ultrasonic wave after passing through the rock model.

Technical Field

The invention relates to the technical field of seismic rock physics research, in particular to a rock modulus measuring system and method.

Background

The most important link is to establish the relationship between seismic elastic parameters (such as longitudinal and transverse wave velocity, rock modulus and the like) and oil and gas reservoir parameters (such as porosity, permeability, fluid saturation and the like) through a seismic rock physical experiment or theoretical model, simulate the environmental conditions such as temperature pressure, saturation and the like of an actual stratum through rock physical experiment equipment, measure the rock modulus under different environmental conditions and directly establish the relationship between the two. Due to different requirements of exploration and development, different experimental methods are needed to test the dynamic or static rock modulus.

The static rock modulus has important significance for oil and gas exploitation, well condition evaluation, brittleness evaluation and the like, and the static modulus measurement mainly comprises static Young modulus and Poisson ratio which are obtained by measuring corresponding stress change and calculating when stress reaches balance under a certain pressure condition of dry or saturated rock.

The dynamic rock modulus is the basis for evaluating reservoir quality and fluid exploration, and the dynamic rock modulus measurement is mainly to simulate the propagation of seismic waves in the rock under a certain pressure condition of dry or saturated rock, and obtain the dynamic Young modulus and Poisson ratio reflecting the rock in a fluctuation state through measurement. Dynamic rock modulus measurements can be divided into high frequency ultrasonic pulse transmission measurements and low frequency stress-strain measurements, depending on the frequency range and the mode of measurement.

However, because the measurement method for the dynamic and static rock modulus has large difference in observation scale, the existing dynamic measurement and static measurement adopt different measurement systems, and it is difficult to ensure that the rock sample is in the same environmental conditions such as pressure, temperature and saturation.

In view of the above problems, no effective solution has been proposed.

Disclosure of Invention

The embodiment of the invention provides a rock modulus measuring system, which is used for measuring the dynamic rock modulus and the static rock modulus of the same rock sample under the same environmental condition and comprises the following steps: the device comprises a sample bearing module, a pressure control module, a static modulus measuring module, a low-frequency dynamic modulus measuring module and a high-frequency dynamic modulus measuring module;

the sample bearing module is used for placing a rock sample;

the pressure control module is used for applying preset pressure to the rock sample;

the static modulus measurement module is used for: collecting stress of a rock sample before and after applying a preset pressure; determining the static Young modulus and the static Poisson ratio of the rock sample according to the stress of the rock sample before and after the preset pressure is applied;

the low-frequency dynamic modulus measuring module is used for: applying vibration forces of different frequencies to the rock sample at a preset pressure, wherein the frequency of the vibration force is lower than a preset frequency threshold; collecting stress changes of the rock sample under different frequency vibration forces; determining the low-frequency dynamic Young modulus and the low-frequency dynamic Poisson ratio of the rock model according to the stress change;

the high-frequency dynamic modulus measuring module is used for: transmitting ultrasonic waves to the rock sample under a preset pressure, wherein the frequency of the ultrasonic waves is higher than a preset frequency threshold value; receiving ultrasonic waves after passing through the rock model; and determining the high-frequency dynamic Young modulus and the high-frequency dynamic Poisson's ratio of the rock sample according to the ultrasonic wave after passing through the rock model.

The embodiment of the invention provides a rock modulus measuring method, which is used for measuring a dynamic rock modulus and a static rock modulus of the same rock sample under the same environmental condition and comprises the following steps:

applying a preset pressure to the rock sample;

collecting stress of a rock sample before and after applying a preset pressure; determining the static Young modulus and the static Poisson ratio of the rock sample according to the stress of the rock sample before and after the preset pressure is applied;

applying vibration forces of different frequencies to the rock sample at a preset pressure, wherein the frequency of the vibration force is lower than a preset frequency threshold; collecting stress changes of the rock sample under different frequency vibration forces; determining the low-frequency dynamic Young modulus and the low-frequency dynamic Poisson ratio of the rock model according to the stress change;

transmitting ultrasonic waves to the rock sample under a preset pressure, wherein the frequency of the ultrasonic waves is higher than a preset frequency threshold value; receiving ultrasonic waves after passing through the rock model; and determining the high-frequency dynamic Young modulus and the high-frequency dynamic Poisson's ratio of the rock sample according to the ultrasonic wave after passing through the rock model.

The embodiment of the invention comprises the following steps: a sample bearing module is used for placing a rock sample; the pressure control module applies preset pressure to the rock sample, so that the rock sample can be in the same environmental condition when different measurements are carried out; the static modulus measurement module is used for collecting stress of the rock sample before and after a preset pressure is applied, and determining the static Young modulus and the static Poisson ratio of the rock sample; the dynamic rock modulus measuring method comprises the steps that a low-frequency dynamic modulus measuring module applies vibrating forces with different frequencies to a rock sample under preset pressure to determine the low-frequency dynamic Young modulus and the low-frequency dynamic Poisson ratio of the rock model, a high-frequency dynamic modulus measuring module transmits ultrasonic waves to the rock sample under the preset pressure to determine the high-frequency dynamic Young modulus and the high-frequency dynamic Poisson ratio of the rock sample according to the ultrasonic waves penetrating through the rock model, a static modulus measuring module, a high-frequency dynamic modulus measuring module and a low-frequency dynamic modulus measuring module can be integrated into a measuring system, the dynamic rock modulus measuring and the static rock modulus measuring of the same rock sample under the same environmental condition are achieved, the contrast of measuring results is high, and reliable basis can be provided for subsequent oil and gas reservoir parameter optimization.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts. In the drawings:

FIG. 1 is a schematic diagram of a rock modulus measurement system according to an embodiment of the invention;

FIG. 2 is a schematic diagram of a concrete structure of a rock modulus measuring system in an embodiment of the invention;

FIG. 3 is a schematic illustration of core sample placement according to an embodiment of the present disclosure;

FIG. 4 is a schematic diagram of a rock modulus measurement method flow in an embodiment of the invention;

FIG. 5 is a graphical representation of the static modulus of an aluminum standard as a function of axial pressure in an embodiment of the present disclosure;

FIG. 6 is a graph illustrating the variation of dynamic modulus of an aluminum standard with frequency in an embodiment of the present invention;

FIG. 7 is a schematic diagram of the dynamic and static Young's modulus varying with water saturation in an embodiment of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention more apparent, the embodiments of the present invention are further described in detail below with reference to the accompanying drawings. The exemplary embodiments and descriptions of the present invention are provided to explain the present invention, but not to limit the present invention.

In order to solve the problem that the existing dynamic measurement and static measurement adopt different measurement systems, and it is difficult to ensure that a rock sample is in the same environmental conditions such as pressure, temperature, saturation and the like, an embodiment of the present invention provides a rock modulus measurement system, which is used for realizing the measurement of dynamic rock modulus and static rock modulus of the same rock sample under the same environmental conditions, fig. 1 is a schematic diagram of a rock modulus measurement system structure in the embodiment of the present invention, as shown in fig. 1, the system includes: the device comprises a sample bearing module 01, a pressure control module 02, a static modulus measuring module 03, a low-frequency dynamic modulus measuring module 04 and a high-frequency dynamic modulus measuring module 05;

wherein, the sample bearing module 01 is used for placing a rock sample;

the pressure control module 02 is used for applying a preset pressure to the rock sample;

the static modulus measurement module 03 is configured to: collecting stress of a rock sample before and after applying a preset pressure; determining the static Young modulus and the static Poisson ratio of the rock sample according to the stress of the rock sample before and after the preset pressure is applied;

the low-frequency dynamic modulus measuring module 04 is configured to: applying vibration forces of different frequencies to the rock sample at a preset pressure, wherein the frequency of the vibration force is lower than a preset frequency threshold; collecting stress changes of the rock sample under different frequency vibration forces; determining the low-frequency dynamic Young modulus and the low-frequency dynamic Poisson ratio of the rock model according to the stress change;

the high-frequency dynamic modulus measuring module 05 is configured to: transmitting ultrasonic waves to the rock sample under a preset pressure, wherein the frequency of the ultrasonic waves is higher than a preset frequency threshold value; receiving ultrasonic waves after passing through the rock model; and determining the high-frequency dynamic Young modulus and the high-frequency dynamic Poisson's ratio of the rock sample according to the ultrasonic wave after passing through the rock model.

As shown in fig. 1, an embodiment of the present invention is implemented by: a sample bearing module is used for placing a rock sample; the pressure control module applies preset pressure to the rock sample, so that the rock sample can be in the same environmental condition when different measurements are carried out; the static modulus measurement module is used for collecting stress of the rock sample before and after a preset pressure is applied, and determining the static Young modulus and the static Poisson ratio of the rock sample; the dynamic rock modulus measuring method comprises the steps that a low-frequency dynamic modulus measuring module applies vibrating forces with different frequencies to a rock sample under preset pressure to determine the low-frequency dynamic Young modulus and the low-frequency dynamic Poisson ratio of the rock model, a high-frequency dynamic modulus measuring module transmits ultrasonic waves to the rock sample under the preset pressure to determine the high-frequency dynamic Young modulus and the high-frequency dynamic Poisson ratio of the rock sample according to the ultrasonic waves penetrating through the rock model, a static modulus measuring module, a high-frequency dynamic modulus measuring module and a low-frequency dynamic modulus measuring module can be integrated into a measuring system, the dynamic rock modulus measuring and the static rock modulus measuring of the same rock sample under the same environmental condition are achieved, the contrast of measuring results is high, and reliable basis can be provided for subsequent oil and gas reservoir parameter optimization.

In one embodiment, the sample support module 01 comprises: go up cushion, lower cushion and lock ring, the rock sample passes through the lock ring to be fixed between last cushion and lower cushion.

In the embodiment of the invention, the rock sample, the upper cushion block, the lower cushion block and the standard sample are connected and fixed through mechanical parts such as a positioning ring, a locking ring and the like, so that the axes of the rock sample and the standard sample can be ensured to be on the same vertical line, the positions of the rock sample and the standard sample can be adjusted at any time, the same sample can be repeatedly used in various measurement experiments, and the measurement precision can be improved, the sample can be recycled.

In one embodiment, the sample support module 01 comprises: the rock sample is arranged in the pressure kettle;

the pressure control module 02 includes:

the axial pressure control unit is used for injecting gas into the pressure kettle through a digital pump and an axial pressure pipeline and controlling the axial pressure applied to the rock sample;

and the confining pressure control unit is used for injecting fluid into the pressure kettle through the digital pump and the confining pressure pipeline and controlling the magnitude of confining pressure applied to the rock sample.

In one embodiment, the pressure control module 01 is further configured to: and controlling the rock sample to be at a preset temperature.

In one embodiment, the pressure control module 01 is further configured to: the rock sample is controlled at a preset fluid saturation.

In specific implementation, fig. 2 is a schematic diagram of a specific structure of a rock modulus measurement system in an embodiment of the present invention, as shown in fig. 2, a sample holding module 01 may include an autoclave, a rock sample and a standard sample may be placed in the autoclave, an existing pressure control module controls a pressure in the autoclave by injecting nitrogen, an axial pressure of the sample is the same as a confining pressure, and flexibility is poor, and a pressure control module 02 in an embodiment of the present invention may include: axle pressure the control unit and enclose the pressure the control unit, the pressure kettle bottom is provided with axle pressure piston post, axle pressure the control unit can be connected to pressure kettle through axle pressure pipeline and axle pressure piston post with the digital pump, and to injecting gas in the pressure kettle, the axle pressure size of control application on the rock sample, can accurate control axle pressure, enclose the pressure the control unit can pass through digital pump and enclose pressure pipeline and inject fluid into pressure kettle, the enclosure pressure size of control application on the rock sample, can realize the independent control of axle pressure and enclosure pressure, the flexibility of pressure control has been improved, can also carry out rock sample temperature control and fluid saturation's continuous control, wherein, pressure, temperature and fluid saturation can set up according to the demand in advance. In conclusion, the pressure control module 02 can realize that the same rock sample is in the same pressure, temperature and fluid saturation conditions in different measurement experiments, and further enhance the contrast of the experiment results obtained by dynamic measurement and static measurement.

In one embodiment, the static modulus measurement module 03 may include:

the strain gauge is used for outputting an electric signal of stress change of the rock sample before and after a preset pressure is applied;

the resistance meter is used for determining the stress of the rock sample before and after the preset pressure is applied according to the electric signal of the stress change;

and the static modulus determining unit is used for determining the static Young modulus and the static Poisson ratio of the rock sample according to the stress of the rock sample before and after the preset pressure is applied.

In one embodiment: the strain gauge is fixed on the surface of the rock sample.

In one embodiment, the strain gage and the rock sample are sealed by a sealant sleeve.

In specific implementation, the static modulus of the rock has important significance for oil and gas exploitation, well condition evaluation, brittleness evaluation and the like, and when stress reaches equilibrium under a certain pressure condition, the static modulus of the rock can be calculated by measuring corresponding strain, wherein the static modulus of the rock mainly comprises Young modulus and Poisson ratio. The strain gauge can be adhered to the surface of a rock sample, the strain gauge and the rock sample are sealed by pouring sealant in the prior art, but the strain gauge and the rock sample can be damaged when the pouring sealant is removed, fig. 3 is a schematic diagram of placing a core sample according to an embodiment of the invention, as shown in fig. 3, the strain gauge and the rock sample can be sealed by a sealing rubber sleeve in the embodiment of the invention, so that the sealing of the sample can be ensured, the strain gauge and the rock sample cannot be damaged when the sealing rubber sleeve is detached, the rock sample can be recycled, in addition, two strain gauges in a vertical direction and a horizontal direction need to be adhered to the surface of the rock sample respectively, the prior art has deviation when the strain gauge is adhered manually, as the measurement of the strain gauge belongs to a nanometer level, a larger measurement error can be caused when the strain gauge is adhered to the deviation, as shown in fig. 3, the embodiment of the invention can customize the strain gauge assembly, the vertical strain gauges and the horizontal strain gauges are fixed on the same backing in the 90-degree vertical direction to form a group, so that the two strain gauges are ensured to be in the same bonding condition, and the measurement error is reduced.

In a specific implementation, the static modulus measuring module 03 may include: the device comprises a strain gauge, a resistance meter and a static modulus determining unit, wherein after a preset pressure, a preset temperature and a preset fluid saturation degree are applied to a rock sample through a pressure control module 02, the strain gauge can output an electric signal of stress change of the rock sample before and after the preset pressure is applied, the resistance meter can be connected with the strain gauge and output stress of the rock sample before and after the preset pressure is applied, the device also comprises a pressure gauge, the pressure gauge can be connected with the resistance meter and record a stress change curve of the surface of the rock sample, the static modulus determining unit can calculate the static Young modulus of the rock sample based on a formula (1) according to the slope of the stress change curve, and the calculation of the static Poisson ratio and the calculation of the principle are consistent with the calculation of the static Young modulus, and the details are omitted here.

E_s＝dσ/dε (1)

Wherein E is_sThe static Young modulus of the rock sample is shown, sigma is a stress value, epsilon is a stress variation, and d is a differential sign.

In one embodiment, the low frequency dynamic modulus measurement module 04 may include:

the vibration exciter is used for applying vibration forces with different frequencies to the rock sample under preset pressure;

the strain gauge is used for outputting an electric signal of stress change of the rock sample under different frequency vibration forces;

the stress change measuring unit is used for determining the change of the voltage amplitude according to the stress change electric signal; determining the stress change of the rock sample under different frequency vibration forces according to the change of the voltage amplitude value;

and the low-frequency dynamic modulus determining unit is used for determining the low-frequency dynamic Young modulus and the low-frequency dynamic Poisson ratio of the rock model according to the stress change of the rock sample under different frequency vibration forces.

During specific implementation, the low-frequency dynamic modulus measuring module 04 can be used for measuring the physical dynamic modulus of the rocks in the seismic frequency range (1-1000 Hz), after the static modulus measuring module 03 is tested, the testing equipment in the low-frequency dynamic modulus measuring module 04 can be switched, wherein strain gauges in the static modulus measuring module 03 and the low-frequency dynamic modulus measuring module 04 can be the same group of strain gauges, and the dynamic and static modulus can be measured in the same position. The vibration exciter can be an Olympus low-frequency exciter, sinusoidal signals with different frequencies subjected to power amplification can be converted into periodic vibration under preset pressure, temperature and fluid saturation, vibration forces with different frequencies are applied to the rock sample, and the strain gauge can output electric signals of stress changes of the rock sample under the vibration forces with different frequencies; the stress change measuring unit can be a broadband signal acquisition device excited by frequency-division harmonic waves and can be connected with the strain gauge, and the change of the voltage amplitude is determined according to the electric signal of the stress change; determining the stress change of the rock sample under different frequency vibration forces according to the change of the voltage amplitude value; the low-frequency dynamic modulus determination can be performed according to stress changes of the rock sample under different frequency vibration forces, the low-frequency dynamic Young modulus of the rock model can be calculated based on the formula (2), the calculated low-frequency dynamic Poisson ratio and the principle are consistent with the principle of calculating the low-frequency dynamic Young modulus, and details are not repeated here, and the measurement and calculation of the seismic wave longitudinal and transverse wave speeds under different frequency conditions can be performed according to the low-frequency dynamic Young modulus and the low-frequency dynamic Poisson ratio.

E_d＝ε_ref/ε_sample×E_ref (2)

Wherein E is_dIs the dynamic Young's modulus, ε, of a rock sample_refIs a reference strain of a standard sample, ε_sampleIs the amount of stress change of the rock sample, E_refIs a standardReference dynamic young's modulus of the sample.

In one embodiment, the high frequency dynamic modulus measurement module 05 may include:

the ultrasonic transmitter is used for transmitting ultrasonic waves to the rock sample under the preset pressure;

an ultrasonic receiver for receiving ultrasonic waves after passing through the rock sample;

the high-frequency dynamic modulus determining unit is used for determining the propagation speed of the ultrasonic wave in the rock sample according to the ultrasonic wave after the ultrasonic wave passes through the rock sample; and determining the high-frequency dynamic Young modulus and the high-frequency dynamic Poisson ratio of the rock sample according to the propagation velocity.

In specific implementation, the high-frequency dynamic modulus measuring module 05 may be configured to measure the rock physical dynamic modulus in the seismic frequency range (10.25 kHz-2 MHz), as shown in fig. 3, P, S in fig. 3 are ultrasonic sensors respectively, an ultrasonic transmitter may be connected to the ultrasonic sensors, and may transmit ultrasonic waves to the rock sample under preset pressure, temperature, and fluid saturation, and an ultrasonic receiver may be connected to the ultrasonic sensors and receive the ultrasonic waves after passing through the rock sample, where acoustic axes of the ultrasonic transmitter and the ultrasonic receiver may be on the same axis, and the high-frequency dynamic modulus determining unit may include: the digital oscilloscope can read the propagation time of the ultrasonic wave in the rock sample, the length of the rock sample is the propagation distance of the ultrasonic wave, the propagation speed of the ultrasonic wave can be obtained by dividing the propagation distance by the propagation time, and the high-frequency dynamic Young modulus and the high-frequency dynamic Poisson ratio of the rock sample can be calculated according to the propagation speed of the ultrasonic wave.

Based on the same inventive concept, the embodiment of the invention also provides a rock modulus measuring method, as the following embodiment. Because the principle of solving the problems of the rock modulus measuring method is similar to that of a rock modulus measuring device, the implementation of the method can be referred to the implementation of the device, and repeated parts are not described again.

An embodiment of the present invention provides a rock modulus measurement method, which is used for implementing measurement of a dynamic rock modulus and a static rock modulus of a same rock sample under the same environmental condition, where fig. 4 is a schematic diagram of a rock modulus measurement method process in an embodiment of the present invention, and as shown in fig. 4, the method includes:

step 401: applying a preset pressure to the rock sample;

step 402: collecting stress of a rock sample before and after applying a preset pressure; determining the static Young modulus and the static Poisson ratio of the rock sample according to the stress of the rock sample before and after the preset pressure is applied;

step 403: applying vibration forces of different frequencies to the rock sample at a preset pressure, wherein the frequency of the vibration force is lower than a preset frequency threshold; collecting stress changes of the rock sample under different frequency vibration forces; determining the low-frequency dynamic Young modulus and the low-frequency dynamic Poisson ratio of the rock model according to the stress change;

step 404: transmitting ultrasonic waves to the rock sample under a preset pressure, wherein the frequency of the ultrasonic waves is higher than a preset frequency threshold value; receiving ultrasonic waves after passing through the rock model; and determining the high-frequency dynamic Young modulus and the high-frequency dynamic Poisson's ratio of the rock sample according to the ultrasonic wave after passing through the rock model.

In one embodiment, step 401 may comprise:

injecting gas into the pressure kettle, and controlling the axial pressure applied to the rock sample;

and injecting fluid into the pressure kettle to control the confining pressure applied to the rock sample.

In one embodiment, step 402 may comprise:

step 4021: outputting an electric signal of stress change of the rock sample before and after the preset pressure is applied;

step 4022: determining the stress of the rock sample before and after the preset pressure is applied according to the electric signal of the stress change;

step 4023: and determining the static Young modulus and the static Poisson ratio of the rock sample according to the stress of the rock sample before and after the preset pressure is applied.

In one embodiment, step 403 may include:

step 4031: the device is used for applying vibration forces with different frequencies to the rock sample under preset pressure;

step 4032: outputting an electric signal of stress change of the rock sample under different frequency vibration forces;

step 4033: determining the change of the voltage amplitude according to the electrical signal of the stress change; determining the stress change of the rock sample under different frequency vibration forces according to the change of the voltage amplitude value;

step 4034: and determining the low-frequency dynamic Young modulus and the low-frequency dynamic Poisson's ratio of the rock model according to the stress change of the rock sample under the vibration forces of different frequencies.

In one embodiment, step 404 may comprise:

step 4041: transmitting ultrasonic waves to a rock sample under a preset pressure;

step 4042: receiving the ultrasonic waves after passing through the rock sample;

step 4043: determining the propagation speed of the ultrasonic wave in the rock sample according to the ultrasonic wave after passing through the rock sample; and determining the high-frequency dynamic Young modulus and the high-frequency dynamic Poisson ratio of the rock sample according to the propagation velocity.

The following is a specific example to facilitate an understanding of how the invention may be practiced.

Firstly, connecting and fixing a rock sample with an upper cushion block, a lower cushion block and a standard sample through mechanical parts such as a positioning ring, a locking ring and the like, wherein the rock sample is compact sandstone A, the porosity is 4.9%, and the permeability is 0.01 mD;

then, the digital pump is respectively connected with the pressure kettle through an axial pressure pipeline, a confining pressure pipeline and a pore pressure pipeline to carry out pressure control, temperature control and continuous control of fluid saturation, so that actual formation conditions can be simulated, and the rock sample is ensured to be under the conditions of preset pressure, temperature and fluid saturation;

then, each device in the static modulus measuring module is connected, the strain gauge is adhered to the surface of the rock sample, the strain gauge and the rock sample are sealed through a sealing rubber sleeve and are arranged in a pressure kettle, and under the conditions of preset pressure, temperature and fluid saturation, telecommunication of stress change of the rock sample before and after the rock sample is applied with preset pressure is output through the strain gaugeThe stress of the rock sample before and after the preset pressure is applied is output through a resistance meter, the stress change curve of the surface of the rock sample is recorded through a pressure meter, the static Young modulus and the static Poisson ratio of the rock sample are calculated according to the slope of the stress change curve, FIG. 5 is a schematic diagram of the change of the static modulus of an aluminum standard part along with the axial pressure in the embodiment of the invention, and in FIG. 5, E_AL1Young's modulus of the first aluminum standard, E_AL2Young's modulus of a second aluminum standard, E_AL3The Young's modulus of the third aluminum standard sample is shown in FIG. 5, the axial pressure is more than 4MPa, and the static Young's modulus measurement result is very stable;

next, switching each device in the low-frequency dynamic modulus measurement module, where the strain gauge in the static modulus measurement module and the strain gauge in the low-frequency dynamic modulus measurement module may be a same set of strain gauges, applying vibration forces of different frequencies to the rock sample through a vibration exciter under preset conditions of pressure, temperature, and fluid saturation, the strain gauges outputting electric signals of stress changes of the rock sample under the vibration forces of different frequencies, and a broadband signal acquisition device excited by a frequency division band harmonic wave acquiring the stress changes of the rock sample under the vibration forces of different frequencies according to the electric signals of the stress changes, and calculating a low-frequency dynamic young modulus and a low-frequency dynamic poisson ratio of the rock model according to the stress changes of the rock sample under the vibration forces of different frequencies, where fig. 6 is a schematic diagram of changes of dynamic modulus of an aluminum standard part with frequency in an embodiment of the present invention, and in fig. 6, E is a young modulus, PR is Poisson's ratio, ERR is error, theoretically, the aluminum standard part has no dispersion, namely the modulus of the aluminum standard part does not change along with frequency, the Young modulus of the aluminum standard part is 74.2GPa, the Poisson's ratio is 0.35, as shown in figure 6, the relative change between the dynamic modulus of the aluminum standard part measured by the embodiment of the invention and the modulus of the aluminum standard part is less than 2%;

and then, switching each device of the high-frequency dynamic modulus measuring module, transmitting ultrasonic waves to the rock sample through an ultrasonic transmitter under the conditions of preset pressure, temperature and fluid saturation, receiving the ultrasonic waves after the ultrasonic waves pass through the rock sample through an ultrasonic receiver, and calculating the high-frequency dynamic Young modulus and the high-frequency dynamic Poisson ratio of the rock sample according to the propagation speed of the ultrasonic waves and the propagation speed of the ultrasonic waves through a high-frequency dynamic modulus determining unit.

Finally, the static modulus measurement result, the low-frequency dynamic modulus measurement result and the high-frequency dynamic modulus measurement result are compared and analyzed, fig. 7 is a schematic diagram of the change of the dynamic and static Young modulus along with the water saturation in the embodiment of the invention, as shown in fig. 7, the low-frequency dynamic modulus is close to the static modulus at higher water saturation, the high-frequency dynamic modulus is far higher than the low-frequency dynamic modulus, strong dispersion is displayed, the change of the static modulus along with the water saturation is higher than the dynamic modulus in relative change, the change trend of the low-frequency modulus along with the saturation can provide direct evidence for seismic fluid prediction, and the comparison and analysis of the dynamic and static data can provide experimental basis for developing fracturing parameter adjustment and reservoir reconstruction parameter optimization.

In summary, the rock modulus measuring system and method provided by the embodiment of the invention have the following technical effects:

(1) the rock sample, the upper cushion block, the lower cushion block and the standard sample are fixed through mechanical parts such as a positioning ring and a locking ring, the strain gauge is adhered to the surface of the rock sample, and the strain gauge and the rock sample are sealed through a sealing rubber sleeve, so that different measurements can be performed on the same rock sample, and the rock sample can be recycled;

(2) the rock sample is subjected to preset pressure and temperature and continuous control of fluid saturation through the pressure control module, so that the rock sample can be in the same environmental condition when different measurements are carried out;

(3) the static modulus measuring module, the high-frequency dynamic modulus measuring module and the low-frequency dynamic modulus measuring module can be integrated in a measuring system, dynamic rock modulus measurement and static rock modulus measurement of the same rock sample under the same environmental condition are achieved, the contrast of measuring results is high, reliable basis can be provided for subsequent oil and gas reservoir parameter optimization, low-frequency dynamic modulus testing data can directly provide experimental data for seismic exploration, experimental rules disclosed by the high-frequency dynamic modulus testing data can provide guidance for theoretical modeling and mechanism analysis, and the change rule of the modulus under the variable saturation frequency variable condition can provide important experimental basis for comprehensive utilization of multi-scale data to conduct fluid quantitative prediction and development fracturing parameter optimization.

As will be appreciated by one skilled in the art, embodiments of the present invention may be provided as a method, system, or computer program product. Accordingly, the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present invention may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein.

The present invention is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each flow and/or block of the flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

The above is only a preferred embodiment of the present invention, and is not intended to limit the present invention, and various modifications and variations of the embodiment of the present invention may occur to those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.