Carbon dioxide fracturing flowback carbon emission monitoring device and monitoring method

Abstract

The invention discloses a carbon dioxide fracturing flowback carbon emission monitoring device and monitoring method, and relates to the technical field of reservoir transformation clean production in the oil and gas industry, the monitoring device comprises a three-phase separator, a gas detection pretreatment module, a gas detection pool, a flow control valve and a data analyzer; the three-phase separator, the gas detection pretreatment module and the gas detection pool are sequentially connected through a pipeline; and the gas detection pool is respectively connected with a flow control valve and a data analyzer. Carbon emission of carbon dioxide fracturing flow-back is monitored, and the real-time carbon emission concentration in the fracturing liquid drainage process, the real-time carbon emission in the fracturing liquid drainage process, the accumulated carbon emission in each stage, the carbon emission in the whole process and a carbon emission distribution rule curve in the fracturing liquid drainage process are obtained through calculation. Therefore, the distribution rule of carbon emission in the flow-back process of the carbon dioxide fracturing site can be mastered in time, and a more reasonable and efficient carbon dioxide trapping and liquefying process can be designed.

Description

Technical Field

[0001] This invention relates to the field of clean production technology for reservoir modification in the oil and gas industry, and more specifically to a carbon dioxide fracturing flowback carbon emission monitoring device and monitoring method. Background Technology

[0002] With the introduction of the "dual carbon" target, carbon dioxide fracturing has rapidly been deployed across major oilfields due to its advantages in carbon utilization and carbon emission reduction. However, this has also led to a significant increase in post-fracturing runoff carbon dioxide emissions. Therefore, it is necessary to research carbon emission monitoring devices and methods for the carbon dioxide fracturing runoff process to promptly understand the distribution patterns of carbon emissions during the process. Based on this, a more rational and efficient carbon dioxide capture and liquefaction process is designed to achieve the recovery and reuse of post-fracturing runoff carbon dioxide. This approach not only reduces carbon emissions but also lowers the cost of carbon dioxide fracturing operations while achieving closed-loop carbon management in carbon dioxide fracturing, laying the foundation for the certification of carbon emission reduction capabilities in carbon dioxide fracturing.

[0003] Therefore, there is an urgent need for a carbon emission monitoring device and method for carbon dioxide fracturing backflow to monitor carbon emissions from carbon dioxide fracturing backflow. Summary of the Invention

[0004] In order to overcome the defects in the prior art, the present invention discloses a carbon dioxide fracturing backflow carbon emission monitoring device and monitoring method for monitoring carbon dioxide fracturing backflow.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] A carbon dioxide fracturing backflow carbon emission monitoring device includes a three-phase separator, a gas detection pretreatment module, a gas detection tank, a flow control valve, and a data analyzer;

[0007] The three-phase separator, gas detection pretreatment module, and gas detection tank are connected in sequence through pipelines. The three-phase separator is used to perform three-phase separation on the carbon dioxide fracturing flowback material. The gas detection pretreatment module is used to filter and dry the gas material after three-phase separation. The gas detection tank is used to detect the gas in the pretreated gas material.

[0008] The gas detection pool is connected to a flow control valve and a data analyzer. The flow control valve is used to control the flow rate of the discharged material after the gas detection pool is detected, and the data analyzer is used to monitor carbon emissions based on the gas detection data and the discharged material flow rate data.

[0009] Preferably, the three-phase separator utilizes the gravity and relative density difference of the materials in the fracturing flowback fluid to achieve three-phase separation. It includes a feed inlet, a gas-liquid separation chamber, a gas phase outlet, a liquid phase outlet, and a solid phase outlet. The separated liquid is metered by a flow meter and discharged through the liquid phase outlet. The separated solid is discharged through the solid phase outlet. The separated gas enters the gas detection and pretreatment module through the gas sampling inlet connected to the gas phase outlet.

[0010] Preferably, the three-phase separator, gas detection pretreatment module, gas detection tank, flow control valve and data analyzer are all fixed in a box. The box is provided with a gas sampling inlet, an exhaust outlet, a standard gas inlet, a power interface and a signal input interface. The box panel is equipped with a touch screen, which is electrically connected to the data analyzer.

[0011] Preferably, a pressure reducing valve is installed on the pipeline between the three-phase separator and the gas sampling inlet.

[0012] Preferably, the gas detection pretreatment module includes a pressure regulating valve, a water vapor separator, a triple filter, a vacuum filter, and a dryer connected in sequence. The inlet of the pressure regulating valve is connected to the gas sampling inlet. The water vapor separator, the triple filter, and the vacuum filter are all connected to a peristaltic drainage pump and a stainless steel water washing tank. The outlet of the dryer is connected to the inlet of the gas detection pretreatment module, and a constant pressure valve is installed on the connecting pipeline.

[0013] Preferably, the gas detection pool is equipped with a carbon dioxide and methane dual-gas detection sensor, a temperature sensor, a pressure sensor, and a constant temperature module. The dual-gas detection sensor is electrically connected to the data analyzer. A flow control valve and an exhaust pump are installed on the outlet pipe of the gas detection pool. The flow control valve is electrically connected to the data analyzer.

[0014] Based on the above-mentioned carbon dioxide fracturing flowback carbon emission monitoring device, the present invention also provides a carbon dioxide fracturing flowback carbon emission monitoring method, comprising the following steps:

[0015] S001. A three-phase separator is used to separate the carbon dioxide fracturing flowback mixture into three phases, and the fracturing flowback gas after three-phase separation is subjected to decompression treatment.

[0016] Preferably, in step S001, a pressure reducing valve connected to the outlet of the three-phase separator is used to reduce the pressure of the carbon dioxide fracturing return gas after the three-phase separation. The pressure reducing valve stably controls the flow rate of the fracturing return gas and adjusts the output pressure within a range of 0-0.4 MPa.

[0017] S002. Use the gas detection pretreatment module to perform dust removal, water removal, and oil removal pretreatment on the fracturing return gas after decompression treatment;

[0018] Preferably, in step S002, the fracturing return gas is filtered using a water-vapor separator, a triple filter, and a vacuum filter, and the filtered water is discharged using a peristaltic drainage pump. Oil and impurities in the fracturing return gas are removed using a stainless steel water washing tank, and finally, the fracturing return gas is dried using a dryer.

[0019] S003. The pressure of the pretreated fracturing backflow gas is adjusted to atmospheric pressure through a constant pressure valve;

[0020] S004. The fracturing return gas after being regulated to atmospheric pressure is sent into the gas detection tank. The two-in-one gas detection sensor in the gas detection tank collects the gas concentration change data in the fracturing return gas in real time, and the constant temperature module controls the temperature of the fracturing return gas.

[0021] Preferably, in step S004, the combined gas detection sensor, temperature sensor, and pressure sensor in the gas detection tank detect the concentration values ​​of carbon dioxide and methane gas, as well as the real-time temperature and pressure values ​​in the fracturing return gas; the constant temperature module in the gas detection tank provides heat tracing for the fracturing return gas throughout the process.

[0022] S005. Calculate the real-time carbon emission concentration during the fracturing fluid drainage process using gas concentration change data;

[0023] Preferably, step S005 includes: the data analyzer acquiring real-time concentration values ​​of carbon dioxide backflow gas and methane emission gas at different stages of the fracturing fluid drainage process; the data analyzer using the real-time gas concentration values ​​at different stages to obtain the real-time carbon emission concentration at different times throughout the fracturing fluid drainage process by summing the volume fractions of the two emission gases.

[0024] Preferably, step S005 includes:

[0025] C T =C 1T +C 2T

[0026] Among them, C T Let C be the real-time carbon emission concentration at time T. 1T Let C be the real-time backflow concentration of carbon dioxide gas at time T. 2T Let C be the real-time emission concentration of methane gas at time T; in the early stage of fracturing fluid drainage, the flowback material is carbon dioxide gas and fracturing flowback fluid, with no methane gas emission, then C 2T C is 0 T =C 1T During the middle stage of fracturing flowback, the flowback materials are carbon dioxide gas, methane gas, and fracturing flowback fluid, then C 1T C 2T All are not 0, C T =C 1T +C2T In the later stages of fracturing fluid drainage, the returned materials are carbon dioxide gas and methane gas, then C 1T C 2T All are not 0, C T =C 1T +C 2T .

[0027] S006. Combining the real-time flow data of the flow control valve and the gas concentration change data of the two-in-one gas detection sensor, calculate the real-time carbon emissions during the fracturing fluid drainage process, the cumulative carbon emissions at each stage, and the total carbon emissions for the entire process.

[0028] Preferably, in step S006, the data analyzer acquires the real-time concentration values ​​of carbon dioxide return gas and methane emission gas at different stages of the fracturing fluid drainage process. Using the real-time gas concentration values ​​at different stages, combined with the real-time flow data in the flow control valve, the real-time carbon emissions of the fracturing fluid drainage process are calculated, and then the cumulative carbon emissions of each stage and the total carbon emissions of the entire fracturing fluid drainage process are calculated.

[0029] Preferably, step S006 includes:

[0030] N T =C 1T ×Q T ×q

[0031] P T =C 2T ×Q T ×g

[0032] S T =N T +P T ×2.75

[0033]

[0034] S w =S e +S m +S l

[0035] Among them, S T N represents the real-time carbon emissions during the fracturing flowback process at time T. T P represents the real-time carbon emissions of carbon dioxide gas at time T. T C represents the real-time carbon emissions of methane gas at time T. 1T Let C be the real-time backflow concentration of carbon dioxide gas at time T. 2T Let Q be the real-time emission concentration of methane gas at time T. THere is the real-time flow data in the flow control valve at time T, where q is the density of carbon dioxide gas at room temperature, and g is the density of methane gas at room temperature; S e This represents the cumulative carbon emissions during the initial stage of fracturing fluid drainage, N ei Let be the i-th real-time carbon dioxide backflow value collected by the dual-function gas detection sensor in the early stage and calculated in the later stage, and let 'a' be the total number of real-time carbon dioxide backflow values ​​collected by the dual-function gas detection sensor in the early stage and calculated in the later stage. Let t be the value of the i-th real-time carbon dioxide backflow value. e The time required to complete data detection and collection in the early stages; S m This represents the cumulative carbon emissions during the mid-term of fracturing fluid drainage, N mi P represents the i-th real-time carbon dioxide backflow value collected by the mid-term dual-gas detection sensor and calculated later. mi t represents the i-th real-time methane emission value collected by the mid-term dual-gas detection sensor and calculated later, b represents the total number of real-time carbon dioxide backflow values ​​collected by the mid-term dual-gas detection sensor and calculated later, and t represents the total number of real-time carbon dioxide backflow values ​​collected by the mid-term dual-gas detection sensor and calculated later. m The time required for mid-term data detection and collection; S l This represents the cumulative carbon emissions during the later stages of fracturing fluid drainage, N li P is the value of the i-th real-time carbon dioxide backflow, collected by the dual-function gas detection sensor and calculated later. li t represents the i-th real-time methane emission value collected by the dual-gas detection sensor and calculated later, c represents the total number of real-time carbon dioxide back-emission values ​​collected by the dual-gas detection sensor and calculated later, and t represents the total number of real-time carbon dioxide back-emission values ​​collected by the dual-gas detection sensor and calculated later. l For the time required to complete data detection and collection in the later stages; S w This represents the carbon emissions during the entire fracturing and drainage process.

[0036] S007. Using the real-time carbon emission concentration, real-time carbon emission amount, and cumulative carbon emission amount at each stage of the fracturing and drainage process, plot the carbon emission distribution curve of the fracturing and drainage process.

[0037] Preferably, in step S007, the data analyzer uses the real-time carbon emission concentration of the fracturing fluid drainage process calculated in step S005 to obtain a graph showing the relationship between "real-time carbon emission concentration and fracturing fluid drainage time"; and uses the real-time carbon emission amount of the fracturing fluid drainage process and the cumulative carbon emission amount of each stage calculated in step S006 to obtain graphs showing the relationship between "real-time carbon emission amount and fracturing fluid drainage time" and "stage process carbon emission amount and different fracturing fluid drainage stages".

[0038] In steps S005-S007, the real-time carbon dioxide backflow concentration, real-time methane emission concentration, and real-time flow data in the flow control valve are used to calculate and plot the real-time carbon emission concentration, real-time carbon emission amount, and cumulative carbon emission amount change curves at each stage, thus visualizing the carbon emission change trend and distribution pattern of the entire carbon dioxide fracturing backflow process.

[0039] The beneficial effects of this invention are:

[0040] The carbon dioxide fracturing flowback carbon emission monitoring device provided by this invention, by setting up multi-stage separation filters and dryers, achieves a filtration accuracy of 0.1µm, ensuring that the sample gas entering the gas detection pool is completely dry and clean, and ensuring that the components of the sample gas are not lost during the processing, greatly reducing the maintenance workload for users, while also ensuring the normal use and analysis of the instrument.

[0041] The carbon emission monitoring method for carbon dioxide fracturing flowback provided by this invention monitors carbon emissions from carbon dioxide fracturing flowback, calculates the real-time carbon emission concentration, real-time carbon emission amount, cumulative carbon emission amount at each stage, total carbon emission amount for the entire process, and carbon emission distribution curve for the fracturing flowback process. This allows for timely understanding of the carbon emission distribution pattern during the carbon dioxide fracturing flowback process, and enables the design of a more rational and efficient carbon dioxide capture and liquefaction process to achieve the recovery and reuse of carbon dioxide flowback after fracturing. Attached Figure Description

[0042] Figure 1 This is a simplified diagram of the connection structure of the carbon dioxide fracturing backflow carbon emission monitoring device of the present invention;

[0043] Figure 2 This is a schematic flowchart of an embodiment of the carbon dioxide fracturing flowback carbon emission monitoring method of the present invention;

[0044] Figure label:

[0045] 1. Three-phase separator; 2. Pressure reducing valve; 3. Gas sampling inlet; 4. Pressure regulating valve; 5. Water vapor separator; 6. Triple filter; 7. Vacuum filter; 8. Dryer; 9. Peristaltic drain pump; 10. Stainless steel washing tank; 11. Constant pressure valve; 12. Two-in-one (CO2, CH4) gas detection sensor; 13. Temperature sensor; 14. Pressure sensor; 15. Thermostatic module; 16. Data analyzer; 17. Flow control valve; 18. Exhaust pump. Detailed Implementation

[0046] The following will provide a clear and complete description of the concept, specific structure, and technical effects of the present invention in conjunction with the embodiments and accompanying drawings, so as to fully understand the purpose, features, and effects of the present invention.

[0047] Example 1

[0048] A carbon dioxide fracturing backflow carbon emission monitoring device, such as Figure 1 As shown, it includes a three-phase separator 1, a gas detection pretreatment module, a gas detection tank, a flow control valve 17, and a data analyzer 16;

[0049] The three-phase separator 1, the gas detection pretreatment module, and the gas detection tank are connected in sequence through pipelines. The three-phase separator 1 is used to perform three-phase separation on the carbon dioxide fracturing flowback material. The gas detection pretreatment module is used to filter and dry the gas material after the three-phase separation. The gas detection tank is used to perform gas detection on the pretreated gas material.

[0050] The gas detection pool is connected to a flow control valve 17 and a data analyzer 16. The flow control valve 17 is used to control the flow rate of the discharged material after the gas detection pool is detected, and the data analyzer 16 is used to monitor carbon emissions based on the gas detection data and the discharged material flow rate data.

[0051] In this embodiment, a gas sampling inlet 3 is connected to the outlet of the three-phase separator 1 and the inlet of the gas detection pretreatment module via a pipeline. The outlet of the gas detection pretreatment module is connected to the inlet of the gas detection pool via a pipeline. The outlet of the gas detection pool is connected to the inlet of the flow control valve 17. The outlet of the gas detection pool is connected to the data analyzer 16. The gas-liquid separator 1, the gas detection pretreatment module, the gas detection pool, the flow control valve 17, and the data analyzer 16 are all fixed in a housing.

[0052] The three-phase separator 1 utilizes the gravity and relative density differences of materials in the fracturing flowback fluid to achieve three-phase separation. It includes a feed inlet, a gas-liquid separation chamber, a gas phase outlet, a liquid phase outlet, and a solid phase outlet. The separated liquid is metered by a flow meter and discharged through the liquid phase outlet. The separated solid is discharged through the solid phase outlet. The separated gas enters the gas detection and pretreatment module through the gas sampling inlet 3 connected to the gas phase outlet.

[0053] The three-phase separator 1, gas detection pretreatment module, gas detection tank, flow control valve 17 and data analyzer 16 are all fixed in a box. The box is equipped with a gas sampling inlet 3, an exhaust port, a standard gas inlet, a power interface and a signal input interface. The box panel is equipped with a touch screen, which is electrically connected to the data analyzer 16.

[0054] In this embodiment, the chassis panel is equipped with a touch screen display, which can intuitively show the working status and analysis values ​​of the data analyzer 16, and can perform functions such as calibration and viewing of the analyzer through touch operation.

[0055] A pressure reducing valve 2 is installed on the pipeline between the three-phase separator 1 and the gas sampling inlet 3. All pipelines use 6mm high-pressure gas pipelines and are connected by quick-connect couplings.

[0056] like Figure 1 As shown, the gas detection pretreatment module includes a pressure regulating valve 4, a water vapor separator 5, a triple filter 6, a vacuum filter 7, and a dryer 8 connected in sequence. The inlet of the pressure regulating valve 4 is connected to the gas sampling inlet 3. The water vapor separator 5, the triple filter 6, and the vacuum filter 7 are all connected to a peristaltic drainage pump 9 and a stainless steel water washing tank 10. The outlet of the dryer 8 is connected to the inlet of the gas detection pretreatment module, and a constant pressure valve 11 is installed on the connecting pipeline.

[0057] In this embodiment, the gas detection pretreatment module includes multiple individual reactors connected in series and / or parallel via solid pipelines. The gas sampling inlet 3 is connected to a pressure regulating valve 4 via a pipeline. The pressure regulating valve 4 is sequentially connected to a multi-stage gas filtration module via pipelines. The multi-stage gas filtration module includes a water vapor separator 5, a triple filter 6, a vacuum filter 7, a peristaltic drainage pump 9, and a stainless steel washing tank 10. The multi-stage gas filtration module and the dryer 8 are connected via pipelines. The dryer contains a high-density molecular sieve desiccant. The dryer and the gas detection tank are connected via pipelines to a constant pressure valve 11.

[0058] like Figure 1 As shown, the gas detection pool is equipped with a carbon dioxide and methane combined gas detection sensor 12, a temperature sensor 13, a pressure sensor 14, and a constant temperature module 15. The combined gas detection sensor 12 is electrically connected to the data analyzer 16. A flow control valve 17 and an exhaust pump 18 are installed on the outlet pipe of the gas detection pool. The flow control valve 17 is electrically connected to the data analyzer 16.

[0059] Example 2

[0060] A method for monitoring carbon dioxide fracturing backflow carbon emissions, such as Figure 2 As shown, it includes the following steps:

[0061] S001. The three-phase separator 1 is used to separate the carbon dioxide fracturing flowback mixture into three phases, and the fracturing flowback gas after the three-phase separation is subjected to decompression treatment.

[0062] S002. Use the gas detection pretreatment module to perform dust removal, water removal, and oil removal pretreatment on the fracturing return gas after decompression treatment;

[0063] S003. The pressure of the pretreated fracturing backflow gas is adjusted to normal pressure through the constant pressure valve 11;

[0064] S004. The fracturing return gas after being regulated to atmospheric pressure is sent into the gas detection tank. The two-in-one gas detection sensor 12 in the gas detection tank collects the gas concentration change data in the fracturing return gas in real time. The constant temperature module 15 controls the temperature of the fracturing return gas.

[0065] S005. Calculate the real-time carbon emission concentration during the fracturing fluid drainage process using gas concentration change data;

[0066] S006. Combining the real-time flow data of the flow control valve 17 and the gas concentration change data of the two-in-one gas detection sensor 12, calculate the real-time carbon emissions during the fracturing and drainage process, and then calculate the cumulative carbon emissions at each stage and the total carbon emissions of the entire process.

[0067] S007. Using the real-time carbon emission concentration, real-time carbon emission amount, and cumulative carbon emission amount at each stage of the fracturing and drainage process, plot the carbon emission distribution curve of the fracturing and drainage process.

[0068] In step S001, pressure reducing valve 2 is connected to the outlet of three-phase separator 1 to stabilize and control the flow rate of sample gas and adjust the output pressure within the range of 0-0.4 MPa.

[0069] In step S002, the sample gas is processed through a multi-stage gas pretreatment module. This includes a water vapor separator (5), a triple filter (6), and a vacuum filter (7), achieving a filtration accuracy of 0.1µm. A long-life peristaltic drain pump (9) automatically drains the gas. A stainless steel water washing tank (10) removes oil and other impurities from the sample gas. Finally, a high-density molecular sieve desiccant is used to dry the sample gas, minimizing interference.

[0070] In step S004, the combined gas detection sensor 12, temperature sensor 13, and pressure sensor 14 in the gas detection cell detect the concentration values ​​of carbon dioxide and methane gas, as well as the real-time temperature and pressure values ​​in the fracturing return gas. A temperature control module is used to heat the sample gas throughout the process, and an intelligent digital display temperature controller makes the temperature controllable.

[0071] In steps S005-S007, relevant calculations are performed using the real-time carbon dioxide gas backflow concentration, real-time methane gas emission concentration, and real-time flow data in the fracturing backflow pipeline. Real-time carbon emission concentration, real-time carbon emission amount, and cumulative carbon emission change curves at each stage are plotted to visualize the carbon emission change trend and distribution pattern throughout the entire carbon dioxide fracturing backflow process.

[0072] Step S005 includes: Data analyzer 16 acquires real-time concentration values ​​of carbon dioxide backflow gas and methane emission gas at different stages of the fracturing fluid drainage process; data analyzer 16 uses the real-time gas concentration values ​​at different stages to obtain the real-time carbon emission concentration at different times throughout the fracturing fluid drainage process by summing the volume fractions of the two emission gases, including:

[0073] C T =C 1T +C 2T

[0074] Among them, C T Let C be the real-time carbon emission concentration at time T. 1T Let C be the real-time backflow concentration of carbon dioxide gas at time T. 2T Let C be the real-time emission concentration of methane gas at time T; in the early stage of fracturing fluid drainage, the flowback material is carbon dioxide gas and fracturing flowback fluid, with no methane gas emission, then C 2T C is 0 T =C 1T During the middle stage of fracturing flowback, the flowback materials are carbon dioxide gas, methane gas, and fracturing flowback fluid, then C 1T C 2T All are not 0, C T =C 1T +C 2T In the later stages of fracturing fluid drainage, the returned materials are carbon dioxide gas and methane gas, then C 1T C 2T All are not 0, C T =C 1T +C 2T .

[0075] In step S006, the data analyzer 16 acquires real-time concentration values ​​of carbon dioxide return gas and methane emission gas at different stages of the fracturing fluid drainage process. Using these real-time gas concentration values ​​at different stages, combined with the real-time flow data from the flow control valve 17, the real-time carbon emissions during the fracturing fluid drainage process are calculated. Furthermore, the cumulative carbon emissions at each stage and the total carbon emissions for the entire fracturing fluid drainage process are calculated, including:

[0076] N T =C 1T ×Q T ×q

[0077] P T =C 2T ×Q T ×g

[0078] S T =N T +P T ×2.75

[0079]

[0080] S w =S e +S m +S l

[0081] Among them, S T N represents the real-time carbon emissions during the fracturing flowback process at time T. T P represents the real-time carbon emissions of carbon dioxide gas at time T. T C represents the real-time carbon emissions of methane gas at time T. 1T Let C be the real-time backflow concentration of carbon dioxide gas at time T. 2T Let Q be the real-time emission concentration of methane gas at time T. T Here is the real-time flow data in the flow control valve at time T, where q is the density of carbon dioxide gas at room temperature, and g is the density of methane gas at room temperature; S e This represents the cumulative carbon emissions during the initial stage of fracturing fluid drainage, N ei Let be the i-th real-time carbon dioxide backflow value collected by the dual-function gas detection sensor in the early stage and calculated in the later stage, and let 'a' be the total number of real-time carbon dioxide backflow values ​​collected by the dual-function gas detection sensor in the early stage and calculated in the later stage. Let t be the value of the i-th real-time carbon dioxide backflow value. e The time required to complete data detection and collection in the early stages; S m This represents the cumulative carbon emissions during the mid-term of fracturing fluid drainage, N mi P represents the i-th real-time carbon dioxide backflow value collected by the mid-term dual-gas detection sensor and calculated later. mi t represents the i-th real-time methane emission value collected by the mid-term dual-gas detection sensor and calculated later, b represents the total number of real-time carbon dioxide backflow values ​​collected by the mid-term dual-gas detection sensor and calculated later, and t represents the total number of real-time carbon dioxide backflow values ​​collected by the mid-term dual-gas detection sensor and calculated later. m The time required for mid-term data detection and collection; S l This represents the cumulative carbon emissions during the later stages of fracturing fluid drainage, N li P is the value of the i-th real-time carbon dioxide backflow, collected by the dual-function gas detection sensor and calculated later. li t represents the i-th real-time methane emission value collected by the dual-gas detection sensor and calculated later, c represents the total number of real-time carbon dioxide back-emission values ​​collected by the dual-gas detection sensor and calculated later, and t represents the total number of real-time carbon dioxide back-emission values ​​collected by the dual-gas detection sensor and calculated later. l For the time required to complete data detection and collection in the later stages; S w This represents the carbon emissions during the entire fracturing and drainage process.

[0082] In step S007, the data analyzer 16 uses the real-time carbon emission concentration of the fracturing fluid drainage process calculated in step S005 to obtain a graph showing the relationship between "real-time carbon emission concentration and fracturing fluid drainage time"; and uses the real-time carbon emission amount and cumulative carbon emission amount of each stage of the fracturing fluid drainage process calculated in step S006 to obtain graphs showing the relationship between "real-time carbon emission amount and fracturing fluid drainage time" and "stage process carbon emission amount and different fracturing fluid drainage stages".

[0083] The embodiments of the present invention have been described in detail above, but the present invention is not limited to the described embodiments. Those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of the present invention, and these equivalents or substitutions are all included within the scope defined by the claims of the present invention.

Claims

1. A carbon dioxide fracturing flowback carbon emission monitoring device, characterized in that, It includes a three-phase separator (1), a gas detection pretreatment module, a gas detection tank, a flow control valve (17), and a data analyzer (16); The three-phase separator (1), the gas detection pretreatment module, and the gas detection pool are connected in sequence through pipelines. The three-phase separator (1) is used to perform three-phase separation on the carbon dioxide fracturing return material. The gas detection pretreatment module is used to filter and dry the gas material after the three-phase separation. The gas detection pool is used to perform gas detection on the pretreated gas material. The gas detection pool is connected to a flow control valve (17) and a data analyzer (16). The flow control valve (17) is used to control the flow rate of the discharged material after the gas detection pool is detected. The data analyzer (16) is used to monitor carbon emissions based on the gas detection data and the discharged material flow rate data.

2. The carbon dioxide fracturing flowback carbon emission monitoring device as described in claim 1, characterized in that, The three-phase separator (1) utilizes the gravity and relative density difference of the materials in the fracturing flowback fluid to achieve three-phase separation. It includes a feed inlet, a gas-liquid separation chamber, a gas phase outlet, a liquid phase outlet, and a solid phase outlet. The separated liquid is metered by a flow meter and discharged through the liquid phase outlet. The separated solid is discharged through the solid phase outlet. The separated gas enters the gas detection pretreatment module through the gas sampling inlet (3) connected to the gas phase outlet.

3. The carbon dioxide fracturing flowback carbon emission monitoring device as described in claim 1, characterized in that, The three-phase separator (1), gas detection pretreatment module, gas detection pool, flow control valve (17) and data analyzer (16) are all fixed in a box. The box is provided with a gas sampling inlet (3), an exhaust port, a standard gas inlet, a power interface and a signal input interface. The box panel is equipped with a touch screen, which is electrically connected to the data analyzer (16). A pressure reducing valve (2) is installed on the pipeline between the three-phase separator (1) and the gas sampling inlet (3).

4. The carbon dioxide fracturing flowback carbon emission monitoring device as described in claim 3, characterized in that, The gas detection pretreatment module includes a pressure regulating valve (4), a water vapor separator (5), a triple filter (6), a vacuum filter (7), and a dryer (8) connected in sequence. The inlet of the pressure regulating valve (4) is connected to the gas sampling inlet (3). The water vapor separator (5), the triple filter (6), and the vacuum filter (7) are all connected to a peristaltic drainage pump (9) and a stainless steel water washing tank (10). The outlet of the dryer (8) is connected to the inlet of the gas detection pretreatment module, and a constant pressure valve (11) is installed on the connecting pipeline.

5. The carbon dioxide fracturing flowback carbon emission monitoring device as described in claim 1, characterized in that, The gas detection pool is equipped with a carbon dioxide and methane combined gas detection sensor (12), a temperature sensor (13), a pressure sensor (14), and a constant temperature module (15). The combined gas detection sensor (12) is electrically connected to the data analyzer (16). A flow control valve (17) and an exhaust pump (18) are installed on the outlet pipe of the gas detection pool. The flow control valve (17) is electrically connected to the data analyzer (16).

6. A method for monitoring carbon emissions from carbon dioxide fracturing flowback, characterized in that, Includes the following steps: S001. Use a three-phase separator (1) to perform three-phase separation on the carbon dioxide fracturing flowback mixture, and perform depressurization treatment on the fracturing flowback gas after three-phase separation. S002. Use the gas detection pretreatment module to perform dust removal, water removal, and oil removal pretreatment on the fracturing return gas after decompression treatment; S003, The pressure of the pretreated fracturing backflow gas is adjusted to normal pressure through the constant pressure valve (11); S004. The fracturing return gas after being regulated to atmospheric pressure is transported into the gas detection pool. The two-in-one gas detection sensor (12) in the gas detection pool collects the gas concentration change data in the fracturing return gas in real time. The constant temperature module (15) controls the temperature of the fracturing return gas. S005. Calculate the real-time carbon emission concentration during the fracturing fluid drainage process using gas concentration change data; S006. Combine the real-time flow data of the flow control valve (17) and the gas concentration change data of the two-in-one gas detection sensor (12) to calculate the real-time carbon emissions, cumulative carbon emissions at each stage, and carbon emissions of the entire process during the fracturing and drainage process. S007. Using the real-time carbon emission concentration, real-time carbon emission amount, and cumulative carbon emission amount at each stage of the fracturing and drainage process, plot the carbon emission distribution curve of the fracturing and drainage process.

7. The method for monitoring carbon emissions from carbon dioxide fracturing flowback as described in claim 6, characterized in that, In step S001, the pressure reducing valve (2) connected to the outlet of the three-phase separator (1) is used to reduce the pressure of the carbon dioxide fracturing return gas after the three-phase separation. The pressure reducing valve (2) stably controls the flow rate of the fracturing return gas and adjusts the output pressure. The adjustment range is 0-0.4 MPa.

8. The method for monitoring carbon emissions from carbon dioxide fracturing flowback as described in claim 6, characterized in that, In step S002, the fracturing return gas is filtered using a water-vapor separator (5), a triple filter (6), and a vacuum filter (7), and the filtered water is discharged using a peristaltic drainage pump (9). Oil and impurities in the fracturing return gas are removed using a stainless steel water washing tank (10), and finally the fracturing return gas is dried using a dryer (8).

9. A method for monitoring carbon emissions from carbon dioxide fracturing flowback as described in claim 6, characterized in that, In step S004, the combined gas detection sensor (12), temperature sensor (13), and pressure sensor (14) in the gas detection pool detect the concentration values ​​of carbon dioxide and methane gas, as well as the real-time temperature and pressure values ​​in the fracturing return gas; the constant temperature module (15) in the gas detection pool provides heat tracing for the fracturing return gas throughout the process.

10. A method for monitoring carbon emissions from carbon dioxide fracturing flowback as described in claim 6, characterized in that, In steps S005-S007, the real-time carbon dioxide gas backflow concentration, real-time methane gas emission concentration, and real-time flow data in the flow control valve (17) are used to calculate and plot the real-time carbon emission concentration, real-time carbon emission amount, and cumulative carbon emission amount change curves at each stage, thus visualizing the carbon emission change trend and distribution pattern of the entire carbon dioxide fracturing backflow process.

11. The method for monitoring carbon emissions from carbon dioxide fracturing flowback as described in claim 6, characterized in that, Step S005 includes: the data analyzer (16) acquires the real-time concentration values ​​of carbon dioxide backflow gas and methane emission gas at different stages of the fracturing and drainage process, and the data analyzer (16) uses the real-time gas concentration values ​​at different stages to obtain the real-time carbon emission concentration at different times in the entire fracturing and drainage process by summing the volume fractions of the two emission gases.

12. The method for monitoring carbon emissions from carbon dioxide fracturing flowback as described in claim 11, characterized in that, Step S005 includes: C T =C 1T +C 2T Among them, C T Let C be the real-time carbon emission concentration at time T. 1T Let C be the real-time backflow concentration of carbon dioxide gas at time T. 2T Let C be the real-time emission concentration of methane gas at time T; in the early stage of fracturing fluid drainage, the flowback material is carbon dioxide gas and fracturing flowback fluid, with no methane gas emission, then C 2T C is 0 T =C 1T During the middle stage of fracturing flowback, the flowback materials are carbon dioxide gas, methane gas, and fracturing flowback fluid, then C 1T C 2T All are not 0, C T =C 1T +C 2T In the later stages of fracturing fluid drainage, the returned materials are carbon dioxide gas and methane gas, then C 1T C 2T All are not 0, C T =C 1T +C 2T .

13. The method for monitoring carbon emissions from carbon dioxide fracturing flowback as described in claim 6, characterized in that, In step S006, the data analyzer (16) acquires the real-time concentration values ​​of carbon dioxide return gas and methane emission gas at different stages of the fracturing and drainage process. Using the real-time gas concentration values ​​at different stages, combined with the real-time flow data in the flow control valve (17), the real-time carbon emission of the fracturing and drainage process is calculated, and then the cumulative carbon emission of each stage and the carbon emission of the entire fracturing and drainage process are calculated.

14. The method for monitoring carbon emissions from carbon dioxide fracturing flowback as described in claim 13, characterized in that, Step S006 includes: N T =C 1T ×Q T ×q P T =C 2T ×Q T ×g S T =N T +P T ×2.75 S w =S e +S m +S l Among them, S T N represents the real-time carbon emissions during the fracturing flowback process at time T. T P represents the real-time carbon emissions of carbon dioxide gas at time T. T C represents the real-time carbon emissions of methane gas at time T. 1T Let C be the real-time backflow concentration of carbon dioxide gas at time T. 2T Let Q be the real-time emission concentration of methane gas at time T. T Here is the real-time flow data in the flow control valve at time T, where q is the density of carbon dioxide gas at room temperature, and g is the density of methane gas at room temperature; S e This represents the cumulative carbon emissions during the initial stage of fracturing fluid drainage, N ei Let be the i-th real-time carbon dioxide backflow value collected by the dual-function gas detection sensor in the early stage and calculated in the later stage, and let 'a' be the total number of real-time carbon dioxide backflow values ​​collected by the dual-function gas detection sensor in the early stage and calculated in the later stage. Let t be the value of the i-th real-time carbon dioxide backflow value. e The time required to complete data detection and collection in the early stages; S m This represents the cumulative carbon emissions during the mid-term of fracturing fluid drainage, N mi P represents the i-th real-time carbon dioxide backflow value collected by the mid-term dual-gas detection sensor and calculated later. mi t represents the i-th real-time methane emission value collected by the mid-term dual-gas detection sensor and calculated later, b represents the total number of real-time carbon dioxide backflow values ​​collected by the mid-term dual-gas detection sensor and calculated later, and t represents the total number of real-time carbon dioxide backflow values ​​collected by the mid-term dual-gas detection sensor and calculated later. m The time required for mid-term data detection and collection; S l This represents the cumulative carbon emissions during the later stages of fracturing fluid drainage, N li P is the value of the i-th real-time carbon dioxide backflow, collected by the dual-function gas detection sensor and calculated later. li t represents the i-th real-time methane emission value collected by the dual-gas detection sensor and calculated later, c represents the total number of real-time carbon dioxide back-emission values ​​collected by the dual-gas detection sensor and calculated later, and t represents the total number of real-time carbon dioxide back-emission values ​​collected by the dual-gas detection sensor and calculated later. l For the time required to complete data detection and collection in the later stages; S w This represents the carbon emissions during the entire fracturing and drainage process.

15. The method for monitoring carbon emissions from carbon dioxide fracturing flowback as described in claim 6, characterized in that, In step S007, the data analyzer (16) uses the real-time carbon emission concentration of the fracturing fluid drainage process calculated in step S005 to obtain a graph of the relationship between "real-time carbon emission concentration and fracturing fluid drainage time"; and uses the real-time carbon emission amount of the fracturing fluid drainage process and the cumulative carbon emission amount of each stage calculated in step S006 to obtain graphs of the relationship between "real-time carbon emission amount - fracturing fluid drainage time" and "stage process carbon emission amount - different fracturing fluid drainage stages".

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