CN112304988A - Method, device and equipment for determining occurrence state of natural gas hydrate - Google Patents
Method, device and equipment for determining occurrence state of natural gas hydrate Download PDFInfo
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- G01N23/00—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00
- G01N23/02—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by transmitting the radiation through the material
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- G01N23/046—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by transmitting the radiation through the material and forming images of the material using tomography, e.g. computed tomography [CT]
Abstract
The embodiment of the specification provides a method, a device and equipment for determining occurrence state of natural gas hydrate. The method comprises the following steps: measuring X-CT image information corresponding to a natural gas hydrate sample in the process of carrying out decompression decomposition on the natural gas hydrate sample; constructing a hydrate three-dimensional data volume corresponding to the natural gas hydrate sample by using the X-CT image information; identifying at least one hydrate sub-block in the hydrate three-dimensional data volume; respectively obtaining the structure type and the structure evaluation value of each hydrate sub-block based on the morphological characteristics of the hydrate sub-blocks; acquiring an Euler coefficient corresponding to the natural gas hydrate sample according to the structure type; and determining the occurrence state of the natural gas hydrate sample through the structure evaluation value and the Euler coefficient. The method quantitatively determines the corresponding occurrence state, further determines the corresponding exploitation scheme according to the occurrence state, and guarantees effective exploitation of the natural gas hydrate.
Description
Technical Field
The embodiment of the specification relates to the technical field of natural gas hydrates, in particular to a method, a device and equipment for determining occurrence states of natural gas hydrates.
Background
The natural gas hydrate is a cage-shaped ice-like solid substance formed by water molecules and gas molecules under the conditions of low temperature and high pressure. The natural gas hydrate has the advantages of high energy density, large resource amount and the like, and is a potential alternative energy source. The exploitation and utilization of the natural gas hydrate can greatly relieve the energy requirement.
Because the natural gas hydrate only stably exists under the conditions of low temperature and high pressure. In the actual development process, even natural gas hydrates with similar initial saturation levels are stored, the occurrence states of the natural gas hydrates are obviously different, such as different occurrence states of a pore filling type, a particle contact type, a contact bearing type and the like. With the exploitation of the natural gas hydrate, the natural gas hydrate under different occurrence states may have different evolution laws under the same exploitation conditions. When the natural gas hydrate is produced in an inappropriate way, the occurrence state of the natural gas hydrate can be influenced, so that the migration capacity of a pore structure, a gas-water two-phase fluid and the like can be influenced, and the production result can be further influenced. Therefore, the determination of the occurrence form of the natural gas hydrate has important guiding significance for capacity prediction and exploitation scheme formulation.
Disclosure of Invention
An object of the embodiments of the present specification is to provide a method, an apparatus, and a device for determining an occurrence state of a natural gas hydrate, so as to solve a problem of how to determine an occurrence form corresponding to a natural gas hydrate.
In order to solve the above technical problem, an embodiment of the present specification provides a method for determining an occurrence state of a natural gas hydrate, including:
measuring X-CT image information corresponding to a natural gas hydrate sample in the process of carrying out decompression decomposition on the natural gas hydrate sample;
constructing a hydrate three-dimensional data volume corresponding to the natural gas hydrate sample by using the X-CT image information;
identifying at least one hydrate sub-block in the hydrate three-dimensional data volume; the hydrate sub-blocks correspond to morphological characteristics;
respectively obtaining the structure type and the structure evaluation value of each hydrate sub-block based on the morphological characteristics of the hydrate sub-blocks; the structure evaluation value is used for representing the structure complexity degree of the hydrate sub-block;
acquiring an Euler coefficient corresponding to the natural gas hydrate sample according to the structure type; the Euler coefficient is used for representing the topological connectivity of the natural gas hydrate sample;
and determining the occurrence state of the natural gas hydrate sample through the structure evaluation value and the Euler coefficient.
An embodiment of the present specification further provides a natural gas hydrate occurrence state determining device, including:
the X-CT image information measuring module is used for measuring X-CT image information corresponding to the natural gas hydrate sample in the process of carrying out decompression decomposition on the natural gas hydrate sample;
the hydrate three-dimensional data volume construction module is used for constructing a hydrate three-dimensional data volume corresponding to the natural gas hydrate sample by using the X-CT image information;
the hydrate sub-block identification module is used for identifying at least one hydrate sub-block in the hydrate three-dimensional data volume; the hydrate sub-blocks correspond to morphological characteristics;
the structure calculating module is used for calculating the structure category and the structure evaluation value of each hydrate sub-block based on the morphological characteristics of the hydrate sub-blocks; the structure evaluation value is used for representing the structure complexity degree of the hydrate sub-block;
the Euler coefficient acquisition module is used for acquiring the Euler coefficient corresponding to the natural gas hydrate sample according to the structure type; the Euler coefficient is used for representing the topological connectivity of the natural gas hydrate sample;
and the occurrence state determining module is used for determining the occurrence state of the natural gas hydrate sample through the structure evaluation value and the Euler coefficient.
The embodiment of the present specification further provides a natural gas hydrate occurrence state determining device, which includes a memory and a processor; the memory to store computer program instructions; the processor to execute the computer program instructions to implement the steps of: measuring X-CT image information corresponding to a natural gas hydrate sample in the process of carrying out decompression decomposition on the natural gas hydrate sample; constructing a hydrate three-dimensional data volume corresponding to the natural gas hydrate sample by using the X-CT image information; identifying at least one hydrate sub-block in the hydrate three-dimensional data volume; the hydrate sub-blocks correspond to morphological characteristics; respectively obtaining the structure type and the structure evaluation value of each hydrate sub-block based on the morphological characteristics of the hydrate sub-blocks; the structure evaluation value is used for representing the structure complexity degree of the hydrate sub-block; acquiring an Euler coefficient corresponding to the natural gas hydrate sample according to the structure type; the Euler coefficient is used for representing the topological connectivity of the natural gas hydrate sample; and determining the occurrence state of the natural gas hydrate sample through the structure evaluation value and the Euler coefficient.
According to the technical scheme provided by the embodiment of the specification, in the process of carrying out depressurization decomposition on the natural gas hydrate sample, the embodiment of the specification acquires the X-CT image information of the natural gas hydrate sample, so that a corresponding hydrate three-dimensional data body can be constructed, the structure evaluation value and the Euler coefficient of each hydrate sub-block of the natural gas hydrate sample are further determined, and the occurrence form of the natural gas hydrate sample is further quantitatively determined. The natural gas hydrate occurrence state determining method is used for detecting the form of the hydrate sample based on X-CT, so that the corresponding occurrence state can be quantitatively determined according to the structural complexity corresponding to the hydrate sub-blocks and the communication condition between the hydrate sub-blocks, a corresponding mining scheme can be determined according to the occurrence state, and effective mining of the natural gas hydrate is guaranteed.
Drawings
In order to more clearly illustrate the embodiments of the present specification 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 described in the specification, and other drawings can be obtained by those skilled in the art without creative efforts.
Fig. 1 is a flowchart of a method for determining an occurrence state of a natural gas hydrate according to an embodiment of the present disclosure;
FIG. 2A is a schematic diagram of X-CT image information according to an embodiment of the present disclosure;
FIG. 2B is a schematic diagram of X-CT image information according to an embodiment of the present disclosure;
FIG. 2C is a schematic diagram of X-CT image information according to an embodiment of the present disclosure;
FIG. 2D is a schematic diagram of X-CT image information according to an embodiment of the present disclosure;
FIG. 3A is a schematic view showing a change in the pore-forming amount of a hydrate according to an embodiment of the present disclosure;
FIG. 3B is a schematic diagram showing the change in the amount of pore formation of a hydrate according to an embodiment of the present disclosure;
FIG. 4 is a schematic diagram of the volume change of a hydrate sub-block according to an embodiment of the present disclosure;
FIG. 5A is a schematic diagram of a connected hydrate cluster according to an embodiment of the disclosure;
FIG. 5B is a schematic illustration of an isolated hydrate mass according to an embodiment of the disclosure;
FIG. 6 is a diagram illustrating a variation of a structural evaluation value according to an embodiment of the present disclosure;
FIG. 7 is a diagram illustrating a variation of Euler coefficients in accordance with an embodiment of the present disclosure;
FIG. 8 is a schematic diagram illustrating the variation of the number of hydrate sub-blocks in the example of the present disclosure;
fig. 9 is a block diagram of a natural gas hydrate occurrence state determination apparatus according to an embodiment of the present disclosure;
fig. 10 is a block diagram of a natural gas hydrate occurrence state determination apparatus according to an embodiment of the present disclosure.
Detailed Description
The technical solutions in the embodiments of the present disclosure will be clearly and completely described below with reference to the drawings in the embodiments of the present disclosure, and it is obvious that the described embodiments are only a part of the embodiments of the present disclosure, and not all of the embodiments. All other embodiments obtained by a person of ordinary skill in the art based on the embodiments in the present specification without any creative effort shall fall within the protection scope of the present specification.
In order to solve the above technical problem, an embodiment of the present specification provides a method for determining an occurrence state of a natural gas hydrate. The execution main body of the natural gas hydrate occurrence state determining method is natural gas hydrate occurrence state determining equipment, and the natural gas hydrate occurrence state determining equipment comprises a server, an industrial personal computer, a Personal Computer (PC) and the like. As shown in fig. 1, the method for determining the natural gas hydrate occurrence state may specifically include the following steps.
S110: and measuring the X-CT image information corresponding to the natural gas hydrate sample in the process of carrying out decompression decomposition on the natural gas hydrate sample.
The gas hydrate sample may be an extracted sample corresponding to a gas hydrate reservoir or a sample prepared based on corresponding reservoir conditions. For example, natural gas hydrate can be produced by using natural sea sand having a particle size of 200 to 600 μm and a sodium chloride solution (degree of mineralization: 3.5%) and methane gas having a purity of 99.99% at 2 ℃ under 8 MPa. In practical application, the natural gas hydrate sample may also be obtained in other manners as needed, and details are not described herein.
The X-CT image information is an image acquired based on a microfocus X-CT technique. Because the gas hydrate sample only maintains a steady state at low temperature and high pressure, if a general scanning imaging technology, such as FIB-SEM, nanoct, helium ion microscope and the like, is adopted, the gas hydrate sample cannot be stably detected due to factors such as ion polishing thermal effect, sample preparation difficulty and the like. Therefore, the micro-focus X-CT technology can be applied to the detection of the pore structure and the microscopic occurrence state of the hydrate deposit by being combined with a low-temperature and high-pressure device.
Specifically, when the X-CT technology is used for scanning, the spatial resolution of a scanned image can be set to be 16.6 μm, namely the pixel size of a rectangular characterization unit body of a truncated CT image is 150 multiplied by 150, and correspondingly, the standard deviation of the effective porosity of the sediment can be enabled to be less than 5.0%.
As shown in fig. 2A, 2B, 2C, and 2D, the gas hydrate sample corresponds to X-CT image information at different stages in the decomposition process, where different image information corresponds to different threshold segmentation results.
In some embodiments, during the depressurization decomposition of the gas hydrate sample, at least one decomposition time may be set, and the X-CT image information corresponding to the gas hydrate sample is acquired at the decomposition times. By acquiring the X-CT image information at different decomposition moments, occurrence states corresponding to the decomposition moments can be acquired in the subsequent analysis process, and the dynamic change situation of the occurrence states of the natural gas hydrate sample can be acquired.
The setting time of the decomposition time and the corresponding interval can be set according to the requirements of practical application, and are not described herein again.
In some embodiments, the gas hydrate sample may be decomposed under reduced pressure using an X-CT experimental facility. The X-CT experimental equipment comprises a pressure control system, a semiconductor temperature control system, an X-ray microfocus CT chromatographic scanner and a high-pressure reaction kettle, namely the X-CT experimental equipment can control the pressure and the temperature of the natural gas hydrate sample and can also utilize the X-ray microfocus CT chromatographic scanner to acquire X-CT image information corresponding to the natural gas hydrate sample, so that the effective operation of the measurement process is ensured.
Correspondingly, in the process of carrying out experiments by using the experimental equipment, the equipment pressure and the sample temperature in the X-CT experimental equipment can also be obtained. Since the natural gas hydrate is decomposed into endothermic reactions accompanied by a significant volume expansion phenomenon, the decomposition process can be adaptively adjusted by acquiring temperature information and pressure information.
When the device pressure and the sample temperature are obtained, the decomposition state corresponding to the natural gas hydrate sample can be determined according to the device pressure and the sample temperature, so that the content of gas-phase and non-gas-phase samples in the device can be correspondingly determined, and the occurrence state of the natural gas hydrate sample is further determined by combining the decomposition state in the subsequent experiment process.
S120: and constructing a hydrate three-dimensional data volume corresponding to the natural gas hydrate sample by using the X-CT image information.
After the X-CT image information is obtained, a hydrate three-dimensional data volume corresponding to the natural gas hydrate sample can be constructed by using the X-CT image information. The hydrate three-dimensional data volume can describe the natural gas hydrate sample according to the constructed shape, so that the morphological characteristics of the hydrate three-dimensional data volume can be accurately identified.
The specific method for constructing the hydrate three-dimensional data volume can be set according to the requirements of practical application, and is not described herein again.
In some embodiments, after the X-CT image information is obtained, digital analysis may be performed on the X-CT image information to realize operations such as intercepting a characterization unit, preprocessing an image, and segmenting a threshold, so that sample component information such as a sediment particle content, a hydrate phase content, a water phase content, and a free gas phase content corresponding to the natural gas hydrate sample can be obtained, and further, a communication state of the natural gas hydrate sample can be better determined in a subsequent step.
The specific process for executing the above operation may be set based on the requirement of the actual application, and is not described herein again.
S130: identifying at least one hydrate sub-block in the hydrate three-dimensional data volume; the hydrate sub-blocks correspond to morphological features.
When the hydrate three-dimensional data volume is obtained, at least one hydrate sub-block can be identified from the hydrate three-dimensional data volume. The hydrate sub-block may be an independent sub-block of the natural gas hydrate sample that is not linked to other hydrate sub-blocks
In some embodiments, the morphological characteristics may include distribution frequency and topological properties of the hydrate sub-blocks. Accordingly, determining the morphological characteristics may be based on the 26-critical domain connectivity principle, and determining the morphological characteristics of the hydrate sub-block by the volume, surface area and contact area with the sediment particles of the hydrate sub-block.
In practical application, other features may also be set as the morphological features, and corresponding calculation is performed based on the requirements of practical application, which is not limited to the above examples and is not described herein again.
S140: respectively obtaining the structure type and the structure evaluation value of each hydrate sub-block based on the morphological characteristics of the hydrate sub-blocks; the structure assessment value is used for representing the structural complexity degree of the hydrate sub-block.
Structural classification the hydrate sub-blocks may be classified on the basis of their structural characteristics.
In some embodiments, the structural classes may include connected hydrate clusters and isolated hydrate masses. Connected hydrate clusters mean that the hydrate sub-blocks are still formed by the union of some smaller hydrate groups, while isolated hydrate blocks are hydrate groups that are gradually isolated as the gas hydrate sample decomposes.
Specifically, the structure category of the hydrate sub-block may be determined according to a comparison result between the volume of the hydrate sub-block and a critical volume threshold. For example, the critical volume threshold may be set to 1.0×107μm3And taking the hydrate sub-blocks with the volume larger than the critical volume threshold value as connected hydrate clusters, and taking the hydrate sub-blocks with the volume smaller than the critical volume threshold value as isolated hydrate blocks.
The structure evaluation value can be used for quantitatively evaluating the structure complexity degree of the hydrate subblock. For example, the structural complexity of the hydrate sub-block may be determined from the ratio between the surface area and the volume of the hydrate sub-block. For example, spheres have the smallest structure estimate, whereas hydrate sub-blocks with more complex structures have larger structure estimates.
In some embodiments, a formula may be utilized
And calculating a structure evaluation value, wherein G is the structure evaluation value, S is the surface area of the hydrate sub-block, and V is the volume of the hydrate sub-block.
Fig. 5A is a schematic diagram of a connected hydrate cluster, whose structure evaluation value is 450.12; fig. 5B is a schematic diagram of an isolated hydrate mass, with a structure evaluation of 1.16, much smaller than a connected hydrate cluster. Therefore, based on the corresponding examples in the above figures, it can be seen that the connected hydrate clusters have a much more complex structure than the isolated hydrate masses.
FIGS. 3A and 3B are schematic diagrams for showing the change of the microscopic amount of hydrate in the partially saturated sediment according to the decomposition process under reduced pressure. Based on the comparison in the figures, it can be seen that the number of isolated hydrate blocks present in the pores of the deposit is much greater than the number of clusters of continuous hydrates. In the decomposition process, the number of continuous hydrate clusters in a partial saturated sediment system is gradually reduced, but the number of isolated hydrate blocks shows an inconsistent evolution law, which is caused by the influence of complex hydrate pore decomposition dynamic behaviors. For a partially saturated sediment system, the number of isolated hydrate blocks is not obviously changed at the initial decomposition stage of the hydrate; when the hydrate saturation degree is reduced to a certain critical value, the number of isolated hydrate blocks is increased sharply.
Figure 4 is a schematic of the volume of the sub-block of hydrate used in the deposit as a function of decomposition. Based on the data in the figures, it can be seen that as hydrate saturation decreases, the average volume of hydrate mass in both sediment systems gradually decreases; the average volume of hydrate lumps present in the pores of a fully saturated deposit is smaller than for a partially saturated deposit.
FIG. 6 is a graph of the structural evaluation of hydrates in two deposit systems as a function of the dynamics of the decomposition process. At the initial stage of decomposition, the average shape factor of a single hydrate mass in a partially saturated deposit gradually increases; when the hydrate saturation is less than 0.15, the average shape factor is drastically reduced, indicating an increase in the number of isolated, spheroidal hydrate masses among the interstitial pores. The geometric topology and degree of irregularity of individual hydrate masses in isolated sediment pores is more complex than for fully saturated sediments.
FIG. 7 is a graph of the Euler coefficient of hydrates versus decomposition dynamics for two sediment systems. The average euler coefficient has a similar trend of change as the hydrate saturation decreases. The average euler coefficient of the hydrate gradually decreases at the initial stage of decomposition, and gradually increases when the saturation degree of the hydrate is less than a critical threshold value. The average euler coefficient of hydrate in partially saturated sediments varied more significantly than in fully saturated sediments, indicating more complex topological connectivity of the hydrate.
S150: acquiring an Euler coefficient corresponding to the natural gas hydrate sample according to the structure type; the Euler coefficient is used to represent topological connectivity of the gas hydrate sample.
According to the structure types of different hydrate sub-blocks, the Euler coefficient of the natural gas hydrate sample can be determined, and the Euler coefficient can be used for representing the topological connectivity of the natural gas hydrate sample. For example, the more smaller isolated hydrate sub-blocks in the natural gas hydrate sample, the poorer the topological connectivity; the less small isolated hydrate sub-blocks in the natural gas hydrate sample, the stronger the topological connectivity.
Specifically, the euler coefficient can be correspondingly determined by the number of isolated hydrates and the number of pore throats of connected hydrate clusters in the natural gas hydrate sample.
In some embodiments, the formula χ ═ β may be utilized0-β1+β2Calculating Euler coefficient, where χ is Euler coefficient, β0Is the number of isolated hydrates, beta, in a gas hydrate sample1The pore throat number of the connected hydrate cluster is beta2The number of isolated water drops surrounded by the hydrate.
Figure 8 is a graph of the dynamic variation of the number of hydrate blocks in two deposits as a function of the decomposition process. At the initial stage of the decomposition experiment, isolated hydrate blocks in partially saturated sediments are easier to decompose, and when the saturation of the hydrate is reduced to a critical threshold, hydrate clusters communicated with pore throats are gradually decomposed, so that the number of the isolated hydrate blocks is increased rapidly, and the topological connectivity of the hydrate is rapidly deteriorated. However, hydrates in a fully saturated deposit system exhibit an opposite decomposition kinetic behavior: the pore-throat communicated hydrate cluster is preferentially decomposed, so that the number of isolated hydrate blocks is continuously increased; when the critical hydrate saturation is reached, a large number of isolated hydrate masses present in the pores begin to decompose and the topological connectivity of the hydrate phase deteriorates. After the hydrate is decomposed, the Euler coefficient approaches zero, which indicates that the hydrate existing in the pores and pore throats has been completely converted into methane gas and liquid water.
In some embodiments, after step S110, sample composition information of the gas hydrate sample may also be determined based on the X-CT image information. The sample component information comprises sediment particle content, hydrate phase content, water phase content and free gas phase content, namely content for representing each component in the natural gas hydrate sample.
Correspondingly, when the Euler coefficient is calculated, the Euler coefficient corresponding to the natural gas hydrate sample can be obtained according to the structure type and the sample component information, so that the accuracy of the calculated Euler coefficient is further guaranteed.
S160: and determining the occurrence state of the natural gas hydrate sample through the structure evaluation value and the Euler coefficient.
After the structure evaluation value and the euler coefficient are obtained, the occurrence form of the natural gas hydrate sample can be determined based on the microscopic occurrence quantity, the occurrence form and the topological connectivity of the natural gas hydrate sample. For example, the corresponding relation between the structure evaluation value and the euler coefficient and the occurrence state can be defined in advance, and the occurrence state actually corresponding to the structure evaluation value and the euler coefficient is determined according to the corresponding relation, so that the quantitative determination of the occurrence state of the natural gas hydrate sample is realized.
In practical application, the occurrence state of the natural gas hydrate sample may also be determined by other manners through the structure evaluation value and the euler coefficient, which is not limited to the above example and is not described herein again.
Based on the introduction of the embodiment, it can be seen that, in the process of performing depressurization decomposition on the natural gas hydrate sample, the method obtains the X-CT image information of the natural gas hydrate sample, so that a corresponding hydrate three-dimensional data volume can be constructed, and further, the structure evaluation value and the euler coefficient of each hydrate sub-block of the natural gas hydrate sample are determined, and further, the occurrence form of the natural gas hydrate sample is quantitatively determined. The natural gas hydrate occurrence state determining method is used for detecting the form of the hydrate sample based on X-CT, so that the corresponding occurrence state can be quantitatively determined according to the structural complexity corresponding to the hydrate sub-blocks and the communication condition between the hydrate sub-blocks, a corresponding mining scheme can be determined according to the occurrence state, and effective mining of the natural gas hydrate is guaranteed.
Based on the natural gas hydrate occurrence state determination method, the present specification also provides an embodiment of a natural gas hydrate occurrence state determination device. As shown in fig. 9, the apparatus for determining an occurrence state of a natural gas hydrate specifically includes the following modules.
The X-CT image information measuring module 910 is configured to measure X-CT image information corresponding to a natural gas hydrate sample during depressurization decomposition of the natural gas hydrate sample;
a hydrate three-dimensional data volume construction module 920, configured to construct a hydrate three-dimensional data volume corresponding to the gas hydrate sample by using the X-CT image information;
a hydrate sub-block identification module 930 configured to identify at least one hydrate sub-block in the hydrate three-dimensional data volume; the hydrate sub-blocks correspond to morphological characteristics;
a structure calculating module 940, configured to calculate a structure category and a structure evaluation value of each hydrate sub-block based on the morphological characteristics of the hydrate sub-block; the structure evaluation value is used for representing the structure complexity degree of the hydrate sub-block;
an euler coefficient obtaining module 950, configured to obtain an euler coefficient corresponding to the gas hydrate sample according to the structure type; the Euler coefficient is used for representing the topological connectivity of the natural gas hydrate sample;
a presence state determining module 960, configured to determine a presence state of the gas hydrate sample according to the structural assessment value and the euler coefficient.
Based on the natural gas hydrate occurrence state determination method, the embodiment of the specification further provides natural gas hydrate occurrence state determination equipment. As shown in fig. 10, the natural gas hydrate occurrence state determination device includes a memory and a processor.
In this embodiment, the memory may be implemented in any suitable manner. For example, the memory may be a read-only memory, a mechanical hard disk, a solid state disk, a U disk, or the like. The memory may be used to store computer program instructions.
In this embodiment, the processor may be implemented in any suitable manner. For example, the processor may take the form of, for example, a microprocessor or processor and a computer-readable medium that stores computer-readable program code (e.g., software or firmware) executable by the (micro) processor, logic gates, switches, an Application Specific Integrated Circuit (ASIC), a programmable logic controller, an embedded microcontroller, and so forth. The processor may execute the computer program instructions to perform the steps of: measuring X-CT image information corresponding to a natural gas hydrate sample in the process of carrying out decompression decomposition on the natural gas hydrate sample; constructing a hydrate three-dimensional data volume corresponding to the natural gas hydrate sample by using the X-CT image information; identifying at least one hydrate sub-block in the hydrate three-dimensional data volume; the hydrate sub-blocks correspond to morphological characteristics; respectively obtaining the structure type and the structure evaluation value of each hydrate sub-block based on the morphological characteristics of the hydrate sub-blocks; the structure evaluation value is used for representing the structure complexity degree of the hydrate sub-block; acquiring an Euler coefficient corresponding to the natural gas hydrate sample according to the structure type; the Euler coefficient is used for representing the topological connectivity of the natural gas hydrate sample; and determining the occurrence state of the natural gas hydrate sample through the structure evaluation value and the Euler coefficient.
The systems, devices, modules or units illustrated in the above embodiments may be implemented by a computer chip or an entity, or by a product with certain functions. One typical implementation device is a computer. In particular, the computer may be, for example, a personal computer, a laptop computer, a cellular telephone, a camera phone, a smartphone, a personal digital assistant, a media player, a navigation device, an email device, a game console, a tablet computer, a wearable device, or a combination of any of these devices.
From the above description of the embodiments, it is clear to those skilled in the art that the present specification can be implemented by software plus a necessary general hardware platform. Based on such understanding, the technical solutions of the present specification may be essentially or partially implemented in the form of software products, which may be stored in a storage medium, such as ROM/RAM, magnetic disk, optical disk, etc., and include instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to execute the methods described in the embodiments or some parts of the embodiments of the present specification.
The embodiments in the present specification are described in a progressive manner, and the same and similar parts among the embodiments are referred to each other, and each embodiment focuses on the differences from the other embodiments. In particular, for the system embodiment, since it is substantially similar to the method embodiment, the description is simple, and for the relevant points, reference may be made to the partial description of the method embodiment.
The description is operational with numerous general purpose or special purpose computing system environments or configurations. For example: personal computers, server computers, hand-held or portable devices, tablet-type devices, multiprocessor systems, microprocessor-based systems, set top boxes, programmable consumer electronics, network PCs, minicomputers, mainframe computers, distributed computing environments that include any of the above systems or devices, and the like.
This description may be described in the general context of computer-executable instructions, such as program modules, being executed by a computer. Generally, program modules include routines, programs, objects, components, data structures, etc. that perform particular tasks or implement particular abstract data types. The specification may also be practiced in distributed computing environments where tasks are performed by remote processing devices that are linked through a communications network. In a distributed computing environment, program modules may be located in both local and remote computer storage media including memory storage devices.
While the specification has been described with examples, those skilled in the art will appreciate that there are numerous variations and permutations of the specification that do not depart from the spirit of the specification, and it is intended that the appended claims include such variations and modifications that do not depart from the spirit of the specification.
Claims (11)
1. A natural gas hydrate occurrence state determination method is characterized by comprising the following steps:
measuring X-CT image information corresponding to a natural gas hydrate sample in the process of carrying out decompression decomposition on the natural gas hydrate sample;
constructing a hydrate three-dimensional data volume corresponding to the natural gas hydrate sample by using the X-CT image information;
identifying at least one hydrate sub-block in the hydrate three-dimensional data volume; the hydrate sub-blocks correspond to morphological characteristics;
respectively obtaining the structure type and the structure evaluation value of each hydrate sub-block based on the morphological characteristics of the hydrate sub-blocks; the structure evaluation value is used for representing the structure complexity degree of the hydrate sub-block;
acquiring an Euler coefficient corresponding to the natural gas hydrate sample according to the structure type; the Euler coefficient is used for representing the topological connectivity of the natural gas hydrate sample;
and determining the occurrence state of the natural gas hydrate sample through the structure evaluation value and the Euler coefficient.
2. The method of claim 1, wherein the measuring the gas hydrate sample corresponds to X-CT image information, comprising:
measuring X-CT image information of the natural gas hydrate sample corresponding to at least one decomposition time;
correspondingly, the determining the occurrence state of the natural gas hydrate sample through the structure evaluation value and the Euler coefficient comprises the following steps:
and determining the occurrence state dynamic change condition of the natural gas hydrate sample through the structure evaluation value and the Euler coefficient corresponding to each decomposition moment.
3. The method of claim 1, wherein the depressurizing the gas hydrate sample comprises:
carrying out decompression decomposition on the natural gas hydrate sample by using X-CT experimental equipment; the X-CT experimental equipment comprises a pressure control system, a semiconductor temperature control system, an X-ray microfocus CT chromatographic scanner and a high-pressure reaction kettle.
4. The method of claim 3, wherein during the depressurizing decomposition of the gas hydrate sample, further comprising:
acquiring equipment pressure and sample temperature in X-CT experimental equipment;
determining a decomposition state corresponding to the gas hydrate sample from the device pressure and the sample temperature;
correspondingly, the determining the occurrence state of the natural gas hydrate sample through the structural evaluation value and the euler coefficient further includes:
and determining the occurrence state of the natural gas hydrate sample by combining the decomposition state through the structure evaluation value and the Euler coefficient.
5. The method of claim 1, wherein after measuring X-CT image information corresponding to the gas hydrate sample during the depressurizing decomposition of the gas hydrate sample, further comprising:
determining sample composition information of the natural gas hydrate sample based on the X-CT image information; the sample component information comprises sediment particle content, hydrate phase content, water phase content and free gas phase content;
correspondingly, the obtaining the euler coefficient corresponding to the natural gas hydrate sample according to the structure type includes:
and acquiring an Euler coefficient corresponding to the natural gas hydrate sample according to the structure type and the sample component information.
6. The method of claim 1, wherein the morphological characteristics include distribution frequency and topological properties of hydrate sub-blocks; the identifying at least one hydrate sub-block in the hydrate three-dimensional data volume comprises:
based on the 26 critical region communication principle, the morphological characteristics of the hydrate sub-block are determined through the volume, the surface area and the contact area with sediment particles of the hydrate sub-block.
7. The method of claim 1, wherein the structure category and the structure evaluation value of each hydrate sub-block are respectively obtained based on the morphological characteristics of the hydrate sub-block; the structure evaluation value is used for representing the structure complexity of the hydrate sub-block and comprises the following steps:
using formulas
And calculating a structure evaluation value, wherein G is the structure evaluation value, S is the surface area of the hydrate sub-block, and V is the volume of the hydrate sub-block.
8. The method of claim 1, wherein the structural classes comprise connected hydrate clusters and isolated hydrate masses; respectively obtaining the structure type and the structure evaluation value of each hydrate sub-block based on the morphological characteristics of the hydrate sub-blocks; the structure evaluation value is used for representing the structure complexity of the hydrate sub-block and comprises the following steps:
and determining the structure class of the hydrate sub-block according to the comparison result between the volume of the hydrate sub-block and the critical volume threshold value.
9. The method of claim 8, wherein the obtaining the euler coefficient corresponding to the gas hydrate sample from the structure type; the Euler coefficient is used for representing the topological connectivity of the natural gas hydrate sample, and comprises the following steps:
using the formula χ ═ β0-β1+β2Calculating Euler coefficient, where χ is Euler coefficient, β0Is the number of isolated hydrates, beta, in a gas hydrate sample1The pore throat number of the connected hydrate cluster is beta2The number of isolated water drops surrounded by the hydrate.
10. A natural gas hydrate occurrence state determination device, characterized by comprising:
the X-CT image information measuring module is used for measuring X-CT image information corresponding to the natural gas hydrate sample in the process of carrying out decompression decomposition on the natural gas hydrate sample;
the hydrate three-dimensional data volume construction module is used for constructing a hydrate three-dimensional data volume corresponding to the natural gas hydrate sample by using the X-CT image information;
the hydrate sub-block identification module is used for identifying at least one hydrate sub-block in the hydrate three-dimensional data volume; the hydrate sub-blocks correspond to morphological characteristics;
the structure calculating module is used for calculating the structure category and the structure evaluation value of each hydrate sub-block based on the morphological characteristics of the hydrate sub-blocks; the structure evaluation value is used for representing the structure complexity degree of the hydrate sub-block;
the Euler coefficient acquisition module is used for acquiring the Euler coefficient corresponding to the natural gas hydrate sample according to the structure type; the Euler coefficient is used for representing the topological connectivity of the natural gas hydrate sample;
and the occurrence state determining module is used for determining the occurrence state of the natural gas hydrate sample through the structure evaluation value and the Euler coefficient.
11. A natural gas hydrate occurrence state determination device comprises a memory and a processor;
the memory to store computer program instructions;
the processor to execute the computer program instructions to implement the steps of: measuring X-CT image information corresponding to a natural gas hydrate sample in the process of carrying out decompression decomposition on the natural gas hydrate sample; constructing a hydrate three-dimensional data volume corresponding to the natural gas hydrate sample by using the X-CT image information; identifying at least one hydrate sub-block in the hydrate three-dimensional data volume; the hydrate sub-blocks correspond to morphological characteristics; respectively obtaining the structure type and the structure evaluation value of each hydrate sub-block based on the morphological characteristics of the hydrate sub-blocks; the structure evaluation value is used for representing the structure complexity degree of the hydrate sub-block; acquiring an Euler coefficient corresponding to the natural gas hydrate sample according to the structure type; the Euler coefficient is used for representing the topological connectivity of the natural gas hydrate sample; and determining the occurrence state of the natural gas hydrate sample through the structure evaluation value and the Euler coefficient.
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