CN114660128A - Coal seam gas saturation evaluation method and device and storage medium - Google Patents
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Abstract
The invention relates to a method, a device and a storage medium for evaluating the gas saturation of a coal seam, wherein the method comprises the following steps: acquiring coal sample electric spectrum curves with different gas saturation conditions; performing inversion according to the coal sample electrical spectrum curve to determine complex resistance parameters; and constructing a model between the complex resistance parameter and the gas saturation according to the complex resistance parameter so as to quantitatively analyze the gas saturation. The method for evaluating the gas saturation of the coal sample is calculated and constructed by utilizing the electric frequency spectrum experimental data of the coal sample under the conditions of high temperature and high pressure, the relationship between the gas saturation condition and complex resistance parameters obtained by the electric frequency spectrum curve of the coal sample is determined, and a corresponding model is constructed, so that the aim of effectively and quantitatively analyzing the gas saturation is fulfilled.
Description
Technical Field
The invention relates to the technical field of exploration and exploitation, in particular to a method and a device for evaluating the gas saturation of a coal seam and a storage medium.
Background
The gas saturation is an important parameter for evaluating the physical properties of the coal reservoir, and the accurate evaluation of the gas saturation has important reference values in the aspects of deep exploration of the effective gas permeability of the stratum, gas-water layer identification and distribution, reserve estimation, rock physical simulation, seismic inversion and the like. At present, the gas content of the coal seam is predicted in a direction, and exploration is usually carried out by using sound, force, electricity and other methods. Because coal seams are generally subjected to greater environmental influences, conventional acoustic methods often fail to obtain more accurate data. The coal seam is electrically explored, the gas content of the coal seam can be accurately predicted, the influence of expanding and the like is avoided, and a good effect is obtained in coal seam exploration.
The coal rock is brittle and fragile, and under the influence of a larger environment, compared with a density compensation method, the resistivity method for predicting the gas content of the coal bed has more advantages. Compared with the common resistivity method, the complex resistivity method can obtain more formation parameters, and the complex resistivity method can be combined with the formation parameters to evaluate the characteristics of the coal reservoir more accurately. However, the researchers at home and abroad have many research results in the direction of the complex resistivity of the rock, but the research of evaluating the gas saturation by utilizing the complex resistivity of the coal under the conditions of high temperature and high pressure is still to be studied further.
In summary, an accurate and effective coal seam gas saturation evaluation method is still lacked under the conditions of high temperature and high pressure, so how to effectively evaluate the gas saturation under the complex conditions is a problem to be solved urgently.
Disclosure of Invention
In view of the above, there is a need to provide a method, an apparatus and a storage medium for evaluating the gas saturation of a coal seam, so as to overcome the problem in the prior art that it is difficult to efficiently evaluate the gas saturation under complicated conditions.
In order to solve the technical problem, the invention provides a coal seam gas saturation evaluation method, which comprises the following steps:
acquiring coal sample electric spectrum curves with different gas saturation conditions;
performing inversion according to the coal sample electrical spectrum curve to determine complex resistance parameters;
and constructing a model between the complex resistance parameter and the gas saturation according to the complex resistance parameter so as to quantitatively analyze the gas saturation.
Further, the acquiring of the coal sample electrical spectrum curves of different gas saturation conditions comprises:
determining complex resistivity according to the voltage and current vectors loaded on the coal sample;
determining a real part of complex resistivity and an imaginary part of complex resistivity according to the complex resistivity;
and determining the coal sample electric frequency spectrum curve according to the real part of the complex resistivity and the imaginary part of the complex resistivity.
Further, the determining the complex resistance parameter by inverting according to the coal sample electrical spectrum curve includes:
performing inversion according to the coal sample electrical spectrum curve to determine electrical spectrum parameters;
and determining the interface polarization frequency and the frequency dispersion according to the electric spectrum parameters.
Further, the electrical spectrum parameters include low-frequency complex resistivity, high-frequency complex resistivity and relaxation time, and the inverting is performed according to the coal sample electrical spectrum curve to determine the electrical spectrum parameters, including:
based on a Cole-Cole model equivalent circuit, performing inversion according to the coal sample electrical spectrum curve, wherein the corresponding model is represented by the following formula:
where ρ represents the coal sample impedance, ρ0Representing the zero-frequency resistivity of the coal sample, m representing the polarizability, omega representing the angular frequency, tau representing the relaxation time, and i representing the imaginary number unit;
and determining the low-frequency complex resistivity, the high-frequency complex resistivity and the relaxation time according to an inversion result.
Further, the determining the interface polarization frequency and the frequency dispersion according to the electrical spectrum parameter includes:
determining the interface polarization frequency according to the reciprocal of relaxation time of the coal sample interface polarization in the electrical spectrum parameters, wherein the interface polarization frequency is a frequency point corresponding to the maximum value of the imaginary part amplitude of the coal sample complex resistivity;
and determining the frequency divergence according to the low-frequency complex resistivity and the high-frequency complex resistivity in the electrical spectrum parameters, wherein the frequency divergence is used for representing the frequency divergence characteristic of the coal sample.
Further, the correspondence between the interface polarization frequency and the relaxation time is expressed by the following formula:
wherein τ represents the relaxation time and FI represents the interface polarization frequency.
Further, the frequency dispersion is expressed by the following formula:
wherein PFE represents the frequency dispersion, RαA modulus, R, representing said low frequency complex resistivityβA modulus value representing the high frequency complex resistivity.
Further, the complex resistance parameters include interface polarization frequency and dispersion, and the constructing a model between the complex resistance parameters and gas saturation according to the complex resistance parameters to quantitatively analyze the gas saturation comprises:
constructing a first linear relation according to different interface polarization frequencies and corresponding gas saturation;
and constructing a second linear relation according to the different frequency dispersion degrees and the corresponding gas saturation degrees.
The invention also provides a coal seam gas saturation evaluation device, which comprises:
the acquisition unit is used for acquiring coal sample electric spectrum curves with different gas saturation conditions;
the processing unit is used for carrying out inversion according to the coal sample electric spectrum curve and determining complex resistance parameters;
and the analysis unit is used for constructing a model between the complex resistance parameter and the gas saturation according to the complex resistance parameter so as to quantitatively analyze the gas saturation.
The invention also provides a computer-readable storage medium, on which a computer program is stored, which, when executed by a processor, implements the method for evaluating the coal seam gas saturation as described above.
Compared with the prior art, the invention has the beneficial effects that: firstly, effectively acquiring coal sample electric spectrum curves with different gas saturation conditions; then, inverting the coal sample electrical spectrum curve, and calculating corresponding complex resistance parameters; and finally, constructing a model between the complex resistance parameter and the gas saturation based on the complex resistance parameter, determining the influence of the complex resistance parameter on the gas saturation, and effectively analyzing the gas saturation through the complex resistance parameter. In summary, the invention provides a method for calculating and constructing to obtain the evaluation coal sample gas saturation by utilizing the electric spectrum experimental data of the coal sample under the conditions of high temperature and high pressure, the relationship between the gas saturation condition and the complex resistance parameter obtained by the electric spectrum curve of the coal sample is determined, the influence of the complex resistance parameter on the gas saturation under different conditions of high temperature and high pressure is effectively explored, a corresponding model is constructed, and the purpose of effectively and quantitatively analyzing the gas saturation can be achieved through the complex resistance parameter based on the model.
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Fig. 1 is a schematic flow chart of an embodiment of a method for evaluating coal seam gas saturation according to the present invention;
FIG. 2 is a schematic flowchart of an embodiment of step S101 in FIG. 1 according to the present invention;
FIG. 3 is a flowchart illustrating an embodiment of step S102 in FIG. 1 according to the present invention;
FIG. 4 is a flowchart illustrating an embodiment of step S302 in FIG. 3 according to the present invention;
FIG. 5 is a flowchart illustrating an embodiment of step S103 in FIG. 1 according to the present invention;
FIG. 6 is a schematic structural diagram of an embodiment of an experimental system provided in the present invention;
FIG. 7 is a graphical representation of an embodiment of complex resistivity for different gas saturations of a coal sample in accordance with the present invention;
FIG. 8 is a cross-sectional view of one embodiment of coal sample gas saturation and interfacial polarization frequency provided by the present invention;
FIG. 9 is a cross-sectional view of an embodiment of coal sample gas saturation and dispersion provided by the present invention;
FIG. 10 is a schematic structural diagram of an embodiment of an apparatus for evaluating coal seam gas saturation provided by the present invention;
fig. 11 is a schematic structural diagram of an embodiment of an electronic device provided in the present invention.
Detailed Description
The accompanying drawings, which are incorporated in and constitute a part of this application, illustrate preferred embodiments of the invention and together with the description, serve to explain the principles of the invention and not to limit the scope of the invention.
In the description of the present invention, the terms "first" and "second" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implying any number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. Further, "plurality" means at least two, e.g., two, three, etc., unless specifically limited otherwise.
Reference throughout this specification to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the present invention. The appearances of the phrase in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. It is explicitly and implicitly understood by one skilled in the art that the described embodiments can be combined with other embodiments.
The invention provides a method and a device for evaluating the gas saturation of a coal seam and a storage medium, wherein the method and the device are used for exploring the influence of complex resistance parameters on the gas saturation under different high-temperature and high-pressure conditions, constructing an evaluation model of the gas saturation and providing a new idea for further improving the accuracy and the efficiency of evaluating the gas saturation of the coal seam under the high-temperature and high-pressure conditions.
Before the description of the embodiments, the related words are paraphrased:
and the coal bed gas saturation: refers to the degree to which the pores of the coal seam are filled with gas. The method is generally obtained from an adsorption isothermal curve, namely the gas saturation is equal to the ratio of the measured gas content to the theoretical gas content corresponding to the original reservoir pressure on the adsorption isothermal curve;
Cole-Cole model: a model for describing dispersion and energy loss in dielectric, inelastic media and power networks, for homogeneous rock ore, the change in complex resistivity with frequency due to induced polarization effects (complex resistivity spectrum) can be represented by the Cole-Cole model, where the potential difference is phase shifted with respect to the supply current due to the presence of induced polarization effects, thus the apparent resistivity is complex, and changes with frequency when other conditions are constant.
Based on the description of the technical terms, the research on evaluating the gas saturation by using the complex resistivity of coal under the conditions of high temperature and high pressure is lacked in the prior art, so that the invention aims to provide an efficient and accurate method for evaluating the gas saturation of the coal bed under the conditions of high temperature and high pressure.
Specific examples are described in detail below:
the embodiment of the invention provides a method for evaluating coal seam gas saturation, and with reference to fig. 1, fig. 1 is a schematic flow chart of an embodiment of the method for evaluating coal seam gas saturation provided by the invention, and the method comprises steps S101 to S103, wherein:
in step S101, coal sample electric spectrum curves with different gas saturation conditions are obtained;
in step S102, performing inversion according to the coal sample electrical spectrum curve, and determining complex resistance parameters;
in step S103, a model between the complex resistance parameter and the gas saturation is constructed according to the complex resistance parameter, so as to quantitatively analyze the gas saturation.
In the embodiment of the invention, firstly, coal sample electrical spectrum curves with different gas saturation conditions are effectively obtained; then, inverting the coal sample electrical spectrum curve, and calculating corresponding complex resistance parameters; and finally, constructing a model between the complex resistance parameter and the gas saturation based on the complex resistance parameter, determining the influence of the complex resistance parameter on the gas saturation, and effectively analyzing the gas saturation through the complex resistance parameter.
As a preferred embodiment, with reference to fig. 2, fig. 2 is a schematic flowchart of an embodiment of step S101 in fig. 1 provided by the present invention, where step S101 includes step S201 to step S203, where:
in step S201, complex resistivity is determined according to the voltage and current vectors loaded on the coal sample;
in step S202, determining a real part of complex resistivity and an imaginary part of complex resistivity according to the complex resistivity;
in step S203, the coal sample electrical spectrum curve is determined according to the real part of the complex resistivity and the imaginary part of the complex resistivity.
In the embodiment of the invention, according to the electric spectrum experiment of the coal sample under the conditions of high temperature and high pressure, the electric spectrum curves of the coal sample under different gas saturation conditions are obtained through measurement, so that the calculation of related parameters is conveniently carried out according to the electric spectrum curves of the coal sample.
In one embodiment of the invention, the pretreated coal sample is placed in the holder, and a pair of measuring electrodes are symmetrically distributed at two ends of the coal sample and fully contact with the end face of the coal sample. The complex resistivity Z is calculated according to the measured voltage and current vectors loaded on the coal sample, and then the real part R and the imaginary part X of the complex resistivity of the coal sample are obtained. When the coal sample is equivalent to a conductor, the complex conductivity is as follows:
σ*(ω)＝iωε*＝σ+iωε
in the above formula, σ is dielectric conductivity; epsilon is a dielectric constant characterizing dielectric polarization of a dielectric, ω ═ 2 π f is an angular frequency, and i is an imaginary unit. The above formula shows that the conductivity of the conductive characteristic of the medium is complex and changes with the frequency.
As a preferred embodiment, the complex resistance parameter includes an interface polarization frequency and a dispersion, and referring to fig. 3, fig. 3 is a schematic flow chart of an embodiment of step S102 in fig. 1 provided by the present invention, and step S102 includes step S301 to step S302, where:
in step S301, performing inversion according to the coal sample electrical spectrum curve to determine electrical spectrum parameters;
in step S302, the interface polarization frequency and the frequency dispersion are determined according to the electrical spectrum parameter.
In the embodiment of the invention, according to the electric spectrum experimental data of the coal sample under the high-temperature and high-pressure conditions, parameters such as low-frequency complex resistivity, high-frequency complex resistivity, relaxation time and the like of the coal sample are obtained based on Cole-Cole model inversion, and then the interface polarization frequency and the dispersion are calculated.
As a preferred embodiment, the electrical spectrum parameters include low-frequency complex resistivity, high-frequency complex resistivity, and relaxation time, and the step S301 specifically includes:
based on a Cole-Cole model equivalent circuit, performing inversion according to the coal sample electrical spectrum curve, wherein the corresponding model is represented by the following formula:
where ρ represents the coal sample impedance, ρ0Representing the zero-frequency resistivity of the coal sample, m representing the polarizability, omega representing the angular frequency, tau representing the relaxation time, and i representing the imaginary number unit;
and determining the low-frequency complex resistivity, the high-frequency complex resistivity and the relaxation time according to an inversion result.
In the embodiment of the invention, effective inversion is carried out according to a Cole-Cole model equivalent circuit, and low-frequency complex resistivity, high-frequency complex resistivity and relaxation time are determined.
As a preferred embodiment, referring to fig. 4, fig. 4 is a schematic flowchart of an embodiment of step S302 in fig. 3 provided by the present invention, where step S302 includes step S401 to step S402, where:
in step S401, determining an interface polarization frequency according to a reciprocal of a relaxation time of the interface polarization of the coal sample in the electrical spectrum parameter, where the interface polarization frequency is a frequency point corresponding to a maximum value of an imaginary part amplitude of the complex resistivity of the coal sample;
in step S402, determining the frequency dispersion according to the low-frequency complex resistivity and the high-frequency complex resistivity in the electrical spectrum parameter, where the frequency dispersion is used to represent the dispersion characteristic of the coal sample.
In the embodiment of the invention, the influence of the gas saturation on the electric frequency dispersion of the coal sample is quantitatively evaluated by utilizing the interface polarization frequency and the divergence, and a new method for evaluating the gas saturation of the coal sample by utilizing the interface polarization frequency and the divergence is constructed.
As a preferred embodiment, the correspondence between the interface polarization frequency and the relaxation time is expressed by the following formula:
wherein τ represents the relaxation time and FI represents the interface polarization frequency.
In the embodiment of the invention, the interface polarization frequency is effectively calculated through the formula.
It should be noted that, as the frequency increases, in a low frequency band, the imaginary part X amplitude of the coal sample complex resistivity increases sharply, and a frequency point corresponding to the maximum value of the imaginary part X amplitude of the coal sample complex resistivity is called an interface polarization frequency FI and is often used to evaluate the frequency dispersion characteristic of the rock. According to the equivalent circuit model, the polarization frequency of the coal sample interface is in certain relation with the relaxation time.
As a preferred embodiment, the frequency dispersion is expressed by the following formula:
wherein PFE represents the frequency dispersion, RαA modulus, R, representing the low frequency complex resistivityβA modulus value representing the high frequency complex resistivity.
In the embodiment of the invention, the frequency dispersion is effectively calculated by the formula.
It should be noted that, in some cases, a double-solution relationship exists between the real part frequency divergence and the saturation of the core, the quantitative evaluation of the core gas saturation by using the real part frequency divergence does not have universality, and compared with the imaginary part modulus and the real part of the complex resistivity, the imaginary part information can better represent the coal sample electrical frequency dispersion characteristics.
In a specific embodiment of the invention, Rα、RβAnd respectively taking 20Hz and 10KHz, substituting the frequency dispersion PFE into the formula to calculate the frequency dispersion PFE, characterizing the frequency dispersion characteristic of the coal sample by using the frequency dispersion, and quantitatively analyzing the relationship among the temperature, the pressure and the gas saturation of the coal sample. And substituting the inverted imaginary modulus value of the high-frequency complex resistivity and the inverted imaginary modulus value of the low-frequency complex resistivity into the formula for calculation.
As a preferred embodiment, the complex resistance parameter includes an interface polarization frequency and a dispersion, and as seen in fig. 5, fig. 5 is a schematic flow chart of an embodiment of step S103 in fig. 1 provided by the present invention, and includes steps S501 to S502, where:
in step S501, a first linear relationship is constructed according to different interface polarization frequencies and their corresponding gas saturation levels;
in step S502, a first linear relationship is constructed according to the different interface polarization frequencies and their corresponding gas saturation levels.
In the embodiment of the invention, the first linear relation is established by utilizing the interface polarization frequency and the gas saturation to be better linear, and the second linear relation is established by utilizing the frequency divergence and the gas saturation to be better linear.
Referring to fig. 6 to 9, fig. 6 is a schematic structural diagram of an embodiment of an experimental system provided by the present invention, fig. 7 is a schematic curve diagram of an embodiment of complex resistivity of a coal sample with different gas saturations provided by the present invention, fig. 8 is a schematic intersection diagram of an embodiment of the gas saturation of the coal sample and an interface polarization frequency provided by the present invention, fig. 9 is a schematic intersection diagram of an embodiment of the gas saturation of the coal sample and a frequency dispersion provided by the present invention, and a main content of the present invention is described with a specific application example:
as shown in fig. 6, the experimental system consists of a high-precision impedance analyzer, a displacement pump, a core holder, a saturation measuring device, a confining pressure pump and a computer (impedance analyzer program control system), wherein the impedance analyzer is used for measuring the complex resistivity of the coal sample in the experiment, the complex resistivity ranges from 20Hz to 10MHz, 101 points are scanned at equal intervals according to logarithm, and the instrument precision can reach 0.8%. Selecting gas (N2) for water driving, setting a high-temperature high-voltage spectrum instrument at room temperature (27 ℃), constant pressure of 3MPa and the pressure of a displacement pump at 0.1MPa, sequentially setting the displacement pressure at 0.2MPa, 0.4MPa, 0.6MPa, 0.8MPa, 1MPa and 1.2MPa along with the increase of the gas saturation in the coal sample, and recording the complex resistivity of the coal sample at different gas saturations, wherein Sg represents the gas saturation of the coal sample as shown in FIG. 7;
as shown in fig. 8, as the saturation of the gas in the coal sample is increased, the interface polarization frequency is increased and shows a good linear relationship;
as shown in fig. 9, as the gas saturation increases, the coal sample dispersion increases and shows a good linear relationship. Therefore, the method has obvious effects of evaluating the temperature, the pressure and the gas saturation of the coal sample by utilizing the imaginary part frequency dispersion of the complex resistivity, and is also a corroboration for the effectiveness of the method.
It should be noted that, based on the coal sample electrical spectrum experiment under the conditions of high temperature and high pressure, the invention discovers that the complex resistivity of the coal sample has a dispersion phenomenon and is influenced by the gas saturation. The method utilizes the interface polarization frequency and the frequency divergence to quantitatively evaluate the influence of the gas saturation on the electrical frequency dispersion of the coal sample, and the result shows that the interface polarization frequency and the gas saturation have a better linear relationship and the frequency divergence and the gas saturation have a better linear relationship.
An embodiment of the present invention further provides a device for evaluating coal seam gas saturation, and with reference to fig. 10, fig. 10 is a schematic structural diagram of an embodiment of the device for evaluating coal seam gas saturation according to the present invention, where the device 1000 for evaluating coal seam gas saturation includes:
an obtaining unit 1001 configured to obtain a master control factor;
the processing unit 1002 is configured to determine a classification category according to the master control factor; the dessert evaluation model is constructed based on the random forest according to the main control factors and the classification categories, and dessert evaluation factors are determined;
an analyzing unit 1003, configured to determine a favorable exploration area for shale gas according to the sweet spot evaluation factor.
The more specific implementation of each unit of the coal seam gas saturation evaluation device can be referred to the description of the coal seam gas saturation evaluation method, and has similar beneficial effects, and details are not repeated here.
The embodiment of the invention also provides a computer-readable storage medium, on which a computer program is stored, and when the program is executed by a processor, the method for evaluating the coal seam gas saturation is implemented.
Generally, computer instructions for carrying out the methods of the present invention may be carried using any combination of one or more computer-readable storage media. Non-transitory computer readable storage media may include any computer readable medium except for the signal itself, which is temporarily propagating.
A computer readable storage medium may be, for example, but not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination of the foregoing. More specific examples (a non-exhaustive list) of the computer readable storage medium would include the following: an electrical connection having one or more wires, a portable computer diskette, a hard disk, a Random Access Memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing. In the context of this document, a computer readable storage medium may be any tangible medium that can contain, or store a program for use by or in connection with an instruction execution system, apparatus, or device.
Computer program code for carrying out operations for aspects of the present invention may be written in any combination of one or more programming languages, including an object oriented programming language such as Java, Smalltalk, C + +, and conventional procedural programming languages, such as the "C" programming language or similar programming languages, and in particular may employ Python languages suitable for neural network computing and TensorFlow, PyTorch-based platform frameworks. The program code may execute entirely on the user's computer, partly on the user's computer, as a stand-alone software package, partly on the user's computer and partly on a remote computer or entirely on the remote computer or server. In the case of a remote computer, the remote computer may be connected to the user's computer through any type of network, including a Local Area Network (LAN) or a Wide Area Network (WAN), or the connection may be made to an external computer (for example, through the Internet using an Internet service provider).
Fig. 11 is a schematic structural diagram of an embodiment of the electronic device provided in the present invention, and with reference to fig. 11, the electronic device 1100 includes a processor 1101, a memory 1102, and a computer program that is stored in the memory 1102 and can be run on the processor 1101, and when the processor 1101 executes the program, the method for evaluating the saturation of coal bed methane as described above is implemented.
As a preferred embodiment, the electronic device 1100 further includes a display 1103 for displaying that the processor 1101 performs the coal seam gas saturation evaluation method as described above.
Illustratively, the computer programs may be partitioned into one or more modules/units, which are stored in memory 1102 and executed by processor 1101 to implement the present invention. One or more modules/units may be a series of computer program instruction segments capable of performing certain functions, the instruction segments describing the execution of a computer program in the electronic device 1100. For example, the computer program may be divided into the obtaining unit 1001, the processing unit 1002 and the analyzing unit 1003 in the above embodiments, and specific functions of each unit are as described above, which are not described herein again.
The electronic device 1100 may be a desktop computer, a notebook, a palm top computer, or a smart phone with an adjustable camera module.
The processor 1101 may be an integrated circuit chip having signal processing capability. The Processor 1101 may be a general-purpose Processor, including a Central Processing Unit (CPU), a Network Processor (NP), and the like; but also Digital Signal Processors (DSPs), Application Specific Integrated Circuits (ASICs), Field-Programmable Gate arrays (FPGAs) or other Programmable logic devices, discrete Gate or transistor logic devices, discrete hardware components. The various methods, steps, and logic blocks disclosed in the embodiments of the present invention may be implemented or performed. A general purpose processor may be a microprocessor or the processor may be any conventional processor or the like.
The Memory 1102 may be, but not limited to, a Random Access Memory (RAM), a Read Only Memory (ROM), a Programmable Read Only Memory (PROM), an Erasable Read Only Memory (EPROM), an electrically Erasable Read Only Memory (EEPROM), and the like. The memory 1102 is configured to store a program, and the processor 1101 executes the program after receiving an execution instruction, and the method defined by the flow disclosed in any of the foregoing embodiments of the present invention may be applied to the processor 1101, or implemented by the processor 1101.
The display 1103 may be an LCD display or an LED display. Such as a display screen on a cell phone.
It is understood that the configuration shown in fig. 11 is only one schematic configuration of the electronic device 1100, and that the electronic device 1100 may include more or less components than those shown in fig. 11. The components shown in fig. 11 may be implemented in hardware, software, or a combination thereof.
According to the computer-readable storage medium and the electronic device provided by the above embodiments of the present invention, the content specifically described for implementing the method for evaluating the coal seam gas saturation according to the present invention may be referred to, and the method has similar beneficial effects to the method for evaluating the coal seam gas saturation according to the above, and details are not repeated herein.
The invention discloses a method, a device and a storage medium for evaluating the gas saturation of a coal bed, which comprises the following steps of firstly, effectively acquiring coal sample electric spectrum curves under different gas saturation conditions; then, inverting the coal sample electrical spectrum curve, and calculating corresponding complex resistance parameters; and finally, constructing a model between the complex resistance parameter and the gas saturation based on the complex resistance parameter, determining the influence of the complex resistance parameter on the gas saturation, and effectively analyzing the gas saturation through the complex resistance parameter.
The technical scheme of the invention provides a method for calculating and constructing by using the electrical spectrum experimental data of the coal sample under the conditions of high temperature and high pressure to obtain the evaluation coal sample gas saturation, determines the relation between the gas saturation condition and the complex resistance parameter obtained by the electrical spectrum curve of the coal sample, effectively explores the influence of the complex resistance parameter on the gas saturation under different conditions of high temperature and high pressure, constructs a corresponding model, and can achieve the purpose of effectively and quantitatively analyzing the gas saturation through the complex resistance parameter based on the model.
The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are included in the scope of the present invention.
Claims (10)
1. A coal seam gas saturation evaluation method is characterized by comprising the following steps:
acquiring coal sample electric spectrum curves with different gas saturation conditions;
performing inversion according to the coal sample electrical spectrum curve to determine complex resistance parameters;
and constructing a model between the complex resistance parameter and the gas saturation according to the complex resistance parameter so as to quantitatively analyze the gas saturation.
2. The method for evaluating the gas saturation of the coal seam according to claim 1, wherein the step of obtaining the electrical spectrum curves of the coal samples under different gas saturation conditions comprises the following steps:
determining complex resistivity according to the voltage and current vectors loaded on the coal sample;
determining a real part of complex resistivity and an imaginary part of complex resistivity according to the complex resistivity;
and determining the coal sample electrical spectrum curve according to the real part of the complex resistivity and the imaginary part of the complex resistivity.
3. The method for evaluating coal seam gas saturation according to claim 2, wherein the complex resistance parameters include interface polarization frequency and divergence, and the inverting according to the coal sample electrical spectrum curve to determine the complex resistance parameters includes:
performing inversion according to the coal sample electrical spectrum curve to determine electrical spectrum parameters;
and determining the interface polarization frequency and the frequency dispersion according to the electric spectrum parameters.
4. The method for evaluating the coal seam gas saturation according to claim 3, wherein the electrical spectrum parameters comprise low-frequency complex resistivity, high-frequency complex resistivity and relaxation time, and the inverting according to the coal sample electrical spectrum curve to determine the electrical spectrum parameters comprises:
based on a Cole-Cole model equivalent circuit, performing inversion according to the coal sample electrical spectrum curve, wherein the corresponding model is represented by the following formula:
where ρ represents the coal sample impedance, ρ0Representing the zero-frequency resistivity of the coal sample, m representing the polarizability, omega representing the angular frequency, tau representing the relaxation time, and i representing the imaginary number unit;
and determining the low-frequency complex resistivity, the high-frequency complex resistivity and the relaxation time according to an inversion result.
5. The method for evaluating coal seam gas saturation according to claim 3, wherein the determining the interface polarization frequency and the frequency divergence according to the electrical spectrum parameter comprises:
determining the interface polarization frequency according to the reciprocal of relaxation time of the coal sample interface polarization in the electrical spectrum parameters, wherein the interface polarization frequency is a frequency point corresponding to the maximum value of the imaginary part amplitude of the complex resistivity of the coal sample;
and determining the frequency divergence according to the low-frequency complex resistivity and the high-frequency complex resistivity in the electrical spectrum parameters, wherein the frequency divergence is used for representing the frequency divergence characteristic of the coal sample.
6. The coal seam gas saturation evaluation method according to claim 5, wherein the correspondence relationship between the interface polarization frequency and the relaxation time is expressed by the following formula:
wherein τ represents the relaxation time and FI represents the interface polarization frequency.
7. The method for evaluating coal seam gas saturation according to claim 5, wherein the frequency dispersion is expressed by the following formula:
wherein PFE represents the frequency dispersion, RαA modulus, R, representing said low frequency complex resistivityβA modulus value representing the high frequency complex resistivity.
8. The method for evaluating coal seam gas saturation according to claim 1, wherein the complex resistance parameters comprise interface polarization frequency and divergence, and the constructing a model between the complex resistance parameters and gas saturation according to the complex resistance parameters to quantitatively analyze the gas saturation comprises:
constructing a first linear relation according to different interface polarization frequencies and corresponding gas saturation;
and constructing a second linear relation according to the different frequency dispersion degrees and the corresponding gas saturation degrees.
9. A coal seam gas saturation evaluation device is characterized by comprising:
the acquisition unit is used for acquiring coal sample electric spectrum curves with different gas saturation conditions;
the processing unit is used for carrying out inversion according to the coal sample electric spectrum curve and determining complex resistance parameters;
and the analysis unit is used for constructing a model between the complex resistance parameter and the gas saturation according to the complex resistance parameter so as to quantitatively analyze the gas saturation.
10. A computer-readable storage medium, on which a computer program is stored, which, when executed by a processor, implements the method for assessing coal seam gas saturation according to any one of claims 1 to 8.
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| CN115015086A (en) * | 2022-07-26 | 2022-09-06 | 中国石油大学(华东) | Complex conductivity based hydrate formation permeability on-site in-situ quantitative evaluation method |
| CN115931667A (en) * | 2022-07-26 | 2023-04-07 | 中国石油大学(华东) | Complex conductivity parameter-based method for evaluating permeability of hydrate-containing sediment sample |
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| CN115015086A (en) * | 2022-07-26 | 2022-09-06 | 中国石油大学(华东) | Complex conductivity based hydrate formation permeability on-site in-situ quantitative evaluation method |
| CN115931667A (en) * | 2022-07-26 | 2023-04-07 | 中国石油大学(华东) | Complex conductivity parameter-based method for evaluating permeability of hydrate-containing sediment sample |
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