A natural gas hydrate exploitation output gas multi-component high-precision stripping identification system and method

Abstract

The present application belongs to the technical field of natural gas hydrate development, and particularly relates to a system and method for high-precision stripping and identification of multiple components of produced gas from natural gas hydrate exploitation. The technical solution is as follows: a system for high-precision stripping and identification of multiple components of produced gas from natural gas hydrate exploitation, comprising a three-dimensional reaction kettle, a gas collection tank, a data collector and a computer, wherein the upper part of the three-dimensional reaction kettle is set as a hydrate synthesis zone, and the lower part is set as a underlying gas cavity, and a temperature and pressure sensing array is arranged in the three-dimensional reaction kettle; the gas collection tank is communicated with the three-dimensional reaction kettle through a pipeline, and a pressure sensor and a temperature sensor are arranged in the gas collection tank; the temperature and pressure sensing array, the pressure sensor and the temperature sensor are connected with the data collector through wires, and the data collector is connected with the computer through wires. The present application can realize accurate stripping and identification of hydrate decomposition gas, free gas in the hydrate synthesis zone and gas contribution of the underlying gas cavity.

Description

Technical Field

[0001] This invention belongs to the field of natural gas hydrate development technology, specifically relating to a high-precision stripping and identification system and method for multi-components in natural gas hydrate extraction. Background Technology

[0002] Natural gas hydrates, as a vast unconventional natural gas resource, pose a significant research challenge worldwide in terms of their safe and efficient extraction. However, in actual production and physical simulation experiments, the produced natural gas is typically a mixture of multiple gas source components. Accurately identifying the contribution ratio of these different gas source components to the total gas production is crucial for scientifically evaluating the effectiveness of extraction methods, calculating hydrate decomposition efficiency, and revealing the dynamic mechanisms of extraction.

[0003] Current experimental techniques lack effective means for identifying and quantitatively separating the gas source components of mixed produced gas. Typically, only macroscopic estimations or empirical extrapolations can be made based on initial reservoir parameters and limited data, failing to accurately quantify the contribution ratios of multiple components such as hydrate decomposition gas and free gas. This leads to a vague understanding of the hydrate decomposition process, gas production timing characteristics, and the contribution of each gas source, becoming a key bottleneck for deepening research on the mechanism of natural gas hydrate extraction and optimizing process parameters. Summary of the Invention

[0004] This invention provides a high-precision stripping and identification system and method for multi-component gas produced in natural gas hydrate extraction, enabling accurate stripping and identification of the contributions of hydrate decomposition gas, free gas in the hydrate synthesis zone, and gas in the underlying gas cavity. This provides key data support for revealing the dynamic mechanism of natural gas hydrate extraction, evaluating extraction efficiency, and optimizing experimental schemes.

[0005] The technical solution of the present invention is as follows:

[0006] A high-precision stripping and identification system for multi-component gas produced from natural gas hydrate extraction includes a three-dimensional reactor, a gas collecting tank, a data acquisition unit, and a computer. The upper part of the three-dimensional reactor is designated as a hydrate synthesis zone, and the lower part as a subsurface gas chamber. A temperature and pressure sensor array is installed inside the three-dimensional reactor. The gas collecting tank is connected to the three-dimensional reactor via pipelines and contains pressure and temperature sensors. The temperature and pressure sensor array, pressure sensors, and temperature sensors are connected to the data acquisition unit via wires, and the data acquisition unit is connected to the computer via wires.

[0007] Furthermore, the high-precision stripping and identification system for multi-component gas produced from natural gas hydrate extraction uses a distributed array network of high-precision temperature sensors and pore pressure sensors to collect spatial temperature gradient changes and pore pressure data in the hydrate synthesis zone and underlying gas cavity.

[0008] Furthermore, the high-precision stripping and identification system for multi-component gas produced from natural gas hydrate extraction includes 20 high-precision temperature sensors, with 10 arranged in the hydrate synthesis zone and 10 arranged in the underlying gas cavity; and 2 pore pressure sensors, with 1 arranged in the hydrate synthesis zone and 1 arranged in the underlying gas cavity.

[0009] Furthermore, in the aforementioned high-precision stripping and identification system for multi-component gas produced during natural gas hydrate extraction, the gas collection tank is used to collect all the gases produced during the extraction process.

[0010] Furthermore, in the aforementioned high-precision stripping and identification system for multi-component gas produced from natural gas hydrate extraction, the data acquisition unit is used to receive, convert, and upload signals collected by the temperature and pressure sensor array, pressure sensor, and temperature sensor to the computer; the computer is used to receive, store, and display the data collected by the data acquisition unit.

[0011] A high-precision stripping and identification method for multi-components in natural gas hydrate extraction produced gas, utilizing the aforementioned high-precision stripping and identification system for multi-components in natural gas hydrate extraction produced gas, includes the following steps:

[0012] 1) Synchronous acquisition of experimental data: Real-time pressure and temperature data of the hydrate synthesis zone and the underlying gas chamber are collected by an array of temperature and pressure sensors deployed in the three-dimensional reactor; real-time pressure and temperature data of the gas collecting tank are collected synchronously by temperature and pressure sensors deployed in the gas collecting tank.

[0013] 2) Calculation of contribution from each gas source: Based on the initial effective volume of the hydrate synthesis zone and the underlying gas chamber, and the pressure and temperature data collected in step 1), the production of free gas in the underlying gas chamber is calculated using the real gas equation of state. and the release of free gas in the hydrate synthesis zone ;

[0014] 3) Separation of gas source contribution: from total gas production The amount of free gas produced in the lower gas chamber calculated in step 2) is gradually deducted. and the release of free gas in the hydrate synthesis zone The amount of residual gas obtained is the amount of hydrate decomposition gas. , .

[0015] Furthermore, in the aforementioned high-precision stripping and identification method for multi-component gas produced from natural gas hydrate extraction, in step 2), the production amount of free gas in the underlying gas cavity... The calculation formula is:

[0016]

[0017] in, These are the initial pressure, gas compressibility factor, and pore volume of the underlying gas cavity, respectively. This represents the initial average temperature of the underlying air chamber; These are the real-time pressure, gas compressibility factor, and pore volume of the underlying gas cavity, respectively. This represents the average real-time temperature of the underlying gas chamber during the pressure drop process; is the gas constant.

[0018] Furthermore, in the aforementioned high-precision stripping and identification method for multi-component gas produced from natural gas hydrate extraction, in step 2), the release amount of free gas in the hydrate synthesis zone... The calculation formula is:

[0019]

[0020] in, These represent the initial pressure, gas compressibility factor, and pore volume of the hydrate synthesis zone, respectively. This represents the initial average temperature of the hydrate synthesis region; These represent the real-time pressure, gas compressibility factor, and pore volume of the hydrate synthesis zone, respectively. This represents the average real-time temperature of the hydrate synthesis zone during the pressure drop process; The value is The increase in pore volume due to hydrate decomposition sum.

[0021] Furthermore, the high-precision stripping and identification method for multi-components in natural gas hydrate extraction includes the method for identifying the increase in pore volume caused by hydrate decomposition. The changes in reservoir physical parameters caused by hydrate decomposition are obtained through inversion calculations, that is, by coupling the material balance principle with temperature and pressure data. The changes in physical parameters are used to infer the changes in hydrate saturation, and then the increase in pore volume caused by hydrate decomposition is calculated.

[0022] Furthermore, the aforementioned high-precision stripping and identification method for multi-component gas produced from natural gas hydrate extraction, with a total gas production... To ensure that the produced gas is collected into a gas collection tank of known volume during the extraction process, the cumulative gas production under standard conditions is calculated by monitoring the real-time pressure and temperature within the collection tank and applying the gas state equation. The calculation formula is as follows:

[0023]

[0024] in, These are the real-time pressure, temperature, and gas compressibility factor inside the gas collecting tank, respectively. This refers to the volume of the gas collection tank.

[0025] The beneficial effects of this invention are as follows:

[0026] 1. This invention achieves quantitative and precise separation of multi-component gases, revealing a profound mechanism. This invention pioneers a "total gas volume - component deduction" calculation method based on full-process experimental data and the real gas law, accurately and quantitatively separating the contributions of hydrate decomposition gas, reservoir free gas, and underlying gas cavity gas from the mixed produced gas for the first time. This solves the bottleneck problem of existing technologies that can only macroscopically estimate and cannot accurately quantify the proportions of each component.

[0027] 2. This invention constructs a data acquisition system to support high-precision calculations. For complex reservoir structures, the system employs a distributed temperature and pressure sensor array to simultaneously acquire spatial profile data of the hydrate synthesis zone and the underlying gas cavity, forming a complete closed loop with the data from the gas collecting tank. This complete, synchronous, and high-precision raw data provides a reliable data foundation for subsequent accurate calculations.

[0028] 3. This invention has a wide range of applications and strong compatibility; it can be seamlessly adapted to depressurization method, heat injection method, chemical agent method and combined mining process, and is applicable to different types of hydrate reservoirs such as marine areas and terrestrial permafrost areas. It provides a transferable technical solution for gas source identification and stripping in actual mining scenarios, and its scope of application far exceeds that of existing single-scenario technologies. Attached Figure Description

[0029] Figure 1 Schematic diagram of a high-precision stripping and identification system for multi-component gas produced from natural gas hydrate extraction;

[0030] Figure 2 This is a schematic diagram of a temperature and pressure sensing array inside a three-dimensional reactor.

[0031] Figure 3 A schematic diagram showing the change in the contribution of gas source over time. Detailed Implementation

[0032] like Figure 1 , 2As shown, a high-precision stripping and identification system for multi-component gas produced from natural gas hydrate extraction includes a three-dimensional reactor 1, a gas collecting tank 4, a data acquisition unit 5, and a computer 6. The upper part of the three-dimensional reactor 1 is designated as a hydrate synthesis zone 2, and the lower part as an underlying gas chamber 3. A temperature and pressure sensing array is installed inside the three-dimensional reactor 1. The temperature and pressure sensing array is a distributed array network composed of high-precision temperature sensors 7 and pore pressure sensors 8. The high-precision temperature sensors 7 are model Pt100, with an accuracy of ±0.1K, and there are 20 of them, with 10 arranged in the hydrate synthesis zone 2 and 10 arranged in the underlying gas chamber 3. The pore pressure sensors 8 are model AISSTEC HM-PT04, and there are 2 of them, with 1 arranged in the hydrate synthesis zone 2 and 1 arranged in the underlying gas chamber 3. They are used to collect spatial temperature gradient changes and pore pressure data in the hydrate synthesis zone 2 and the underlying gas chamber 3. The gas collecting tank 4 is used to collect all the gas produced during the mining process. The gas collecting tank 4 is connected to the three-dimensional reaction vessel 1 via a pipeline. The gas collecting tank 4 is equipped with a pressure sensor and a temperature sensor. The pressure sensor array, pressure sensor, and temperature sensor are connected to the data acquisition unit 5 via wires. The data acquisition unit 5 is connected to the computer 6 via wires. The data acquisition unit 5 is used to receive, convert, and upload the signals collected by the pressure sensor array, pressure sensor, and temperature sensor to the computer 6. The computer 6 is used to receive, store, and display the data collected by the data acquisition unit.

[0033] A high-precision stripping and identification method for multi-components in natural gas hydrate extraction produced gas, utilizing the aforementioned high-precision stripping and identification system for multi-components in natural gas hydrate extraction produced gas, includes the following steps:

[0034] 1) Synchronous acquisition of experimental data: With depressurization mining initiated, the real-time pressure of the hydrate synthesis zone is continuously and synchronously acquired through a temperature and pressure sensor array deployed within the three-dimensional reactor. ,temperature and the real-time pressure of the underlying air chamber. ,temperature The real-time pressure inside the gas collecting tank is simultaneously collected by temperature and pressure sensors installed in the tank. ,temperature data;

[0035] 2) Calculation of contribution from each gas source: Based on the initial effective volume of the hydrate synthesis zone and the underlying gas chamber, and the pressure and temperature data collected in step 1), the production of free gas in the underlying gas chamber is calculated using the real gas equation of state. and the release of free gas in the hydrate synthesis zone ;

[0036] Production of free gas in the subsurface air chamber The calculation formula is:

[0037]

[0038] in, These are the initial pressure, gas compressibility factor, and pore volume of the underlying gas cavity, respectively. This represents the initial average temperature of the underlying air chamber; These are the real-time pressure, gas compressibility factor, and pore volume of the underlying gas cavity, respectively. This represents the average real-time temperature of the underlying gas chamber during the pressure drop process, i.e. The average value; It is the gas constant;

[0039] Release of free gas in the hydrate synthesis zone The calculation formula is:

[0040]

[0041] in, These represent the initial pressure, gas compressibility factor, and pore volume of the hydrate synthesis zone, respectively. This represents the initial average temperature of the hydrate synthesis region; These represent the real-time pressure, gas compressibility factor, and pore volume of the hydrate synthesis zone, respectively. This represents the average real-time temperature of the hydrate synthesis zone during the pressure drop process, i.e. The average value; The value is The increase in pore volume due to hydrate decomposition sum;

[0042] Increase in pore volume due to hydrate decomposition The changes in reservoir physical parameters caused by hydrate decomposition are obtained through inversion calculations, that is, by coupling the material balance principle with temperature and pressure data; the changes in physical parameters are used to deduce the changes in hydrate saturation, and then the increase in pore volume caused by hydrate decomposition is calculated.

[0043] 3) Total gas production To ensure that the produced gas is collected into a gas collection tank of known volume during the extraction process, the cumulative gas production under standard conditions is calculated by monitoring the real-time pressure and temperature within the collection tank and applying the gas state equation. The calculation formula is as follows:

[0044]

[0045] in, These are the real-time pressure, temperature, and gas compressibility factor inside the gas collecting tank, respectively. This refers to the volume of the gas collection tank;

[0046] 4) Separation of gas source contribution: from total gas production The amount of free gas produced in the lower gas chamber calculated in step 2) is gradually deducted. and the release of free gas in the hydrate synthesis zone The amount of residual gas obtained is the amount of hydrate decomposition gas. , .

[0047] By processing the experimental data using the above procedure, it was successfully achieved that different gas source components and hydrate decomposition gas in the mixed product gas could be analyzed. Free gas in the hydrate synthesis zone , lower air cavity air High-precision quantitative stripping and identification of contribution. For example... Figure 3 As shown, the method of the present invention can clearly reveal the dynamic production patterns and contribution ratios of each gas source during continuous extraction. This embodiment verifies the effectiveness and reliability of the method and system.

[0048] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention in any way. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention shall still fall within the scope of the technical solution of the present invention.

Claims

1. A high-precision stripping and identification system for multi-components in natural gas hydrate extraction, characterized in that, The system includes a three-dimensional reactor, a gas collecting tank, a data acquisition unit, and a computer. The upper part of the three-dimensional reactor is designated as a hydrate synthesis zone, and the lower part as a submerged gas chamber. A temperature and pressure sensor array is installed inside the three-dimensional reactor. The gas collecting tank is connected to the three-dimensional reactor via pipelines and contains pressure and temperature sensors. The temperature and pressure sensor array, pressure sensors, and temperature sensors are connected to the data acquisition unit via wires, and the data acquisition unit is connected to the computer via wires.

2. The high-precision stripping and identification system for multi-component gas produced from natural gas hydrate extraction according to claim 1, characterized in that, The temperature and pressure sensing array is a distributed array network composed of high-precision temperature sensors and pore pressure sensors, used to collect spatial temperature gradient changes and pore pressure data in the hydrate synthesis zone and the underlying gas cavity.

3. The high-precision stripping and identification system for multi-component gas produced from natural gas hydrate extraction according to claim 2, characterized in that, There are 20 high-precision temperature sensors, with 10 arranged in the hydrate synthesis zone and 10 arranged in the underlying gas cavity; there are 2 pore pressure sensors, with 1 arranged in the hydrate synthesis zone and 1 arranged in the underlying gas cavity.

4. The high-precision stripping and identification system for multi-component gas produced from natural gas hydrate extraction according to claim 1, characterized in that, The gas collection tank is used to collect all the gases produced during the mining process.

5. The high-precision stripping and identification system for multi-component gas produced from natural gas hydrate extraction according to claim 1, characterized in that, The data acquisition unit is used to receive, convert, and upload signals collected by the temperature and pressure sensor array, pressure sensor, and temperature sensor to the computer; the computer is used to receive, store, and display the data collected by the data acquisition unit.

6. A high-precision stripping and identification method for multi-components in natural gas hydrate extraction, characterized in that, The high-precision stripping and identification system for multi-components of natural gas hydrate extraction produced gas as described in any one of claims 1-5 includes the following steps: 1) Synchronous acquisition of experimental data: Real-time pressure and temperature data of the hydrate synthesis zone and the underlying gas chamber are collected by an array of temperature and pressure sensors deployed in the three-dimensional reactor; real-time pressure and temperature data of the gas collecting tank are collected synchronously by temperature and pressure sensors deployed in the gas collecting tank. 2) Calculation of contribution from each gas source: Based on the initial effective volume of the hydrate synthesis zone and the underlying gas chamber, and the pressure and temperature data collected in step 1), the production of free gas in the underlying gas chamber is calculated using the real gas equation of state. and the release of free gas in the hydrate synthesis zone ; 3) Separation of gas source contribution: from total gas production The amount of free gas produced in the lower gas chamber calculated in step 2) is gradually deducted. and the release of free gas in the hydrate synthesis zone The amount of residual gas obtained is the amount of hydrate decomposition gas. , .

7. The high-precision stripping and identification method for multi-components of natural gas hydrate extraction gas according to claim 6, characterized in that, In step 2), the amount of free gas produced in the lower gas chamber The calculation formula is: in, These are the initial pressure, gas compressibility factor, and pore volume of the underlying gas cavity, respectively. This represents the initial average temperature of the underlying air chamber; These are the real-time pressure, gas compressibility factor, and pore volume of the underlying gas cavity, respectively. This represents the average real-time temperature of the underlying gas chamber during the pressure drop process; is the gas constant.

8. The high-precision stripping and identification method for multi-components in natural gas hydrate extraction as described in claim 7, characterized in that, In step 2), the amount of free gas released from the hydrate synthesis zone The calculation formula is: in, These represent the initial pressure, gas compressibility factor, and pore volume of the hydrate synthesis zone, respectively. This represents the initial average temperature of the hydrate synthesis region; These represent the real-time pressure, gas compressibility factor, and pore volume of the hydrate synthesis zone, respectively. This represents the average real-time temperature of the hydrate synthesis zone during the pressure drop process; The value is The increase in pore volume due to hydrate decomposition sum.

9. The high-precision stripping and identification method for multi-components in natural gas hydrate extraction as described in claim 8, characterized in that, Increase in pore volume due to hydrate decomposition The changes in reservoir physical parameters caused by hydrate decomposition are obtained through inversion calculations, that is, by coupling the material balance principle with temperature and pressure data. The changes in physical parameters are used to infer the changes in hydrate saturation, and then the increase in pore volume caused by hydrate decomposition is calculated.

10. The high-precision stripping and identification method for multi-components of natural gas hydrate extraction gas according to claim 7, characterized in that, Total gas production To collect the produced gas during the extraction process into a gas collection tank of known volume, the cumulative gas production under standard conditions is calculated by monitoring the real-time pressure and temperature inside the gas collection tank and combining it with the gas state equation. The calculation formula is: in, These are the real-time pressure, temperature, and gas compressibility factor inside the gas collecting tank, respectively. This refers to the volume of the gas collection tank.

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