Method for judging reaction degree of underground fire area based on isotope labeling

Abstract

The invention discloses a method for judging the reaction degree of an underground fire area based on isotope labeling, which comprises the following steps of: injecting 2H-labeled 2H2O and 2O, enabling the 2H2O and the 2O to reach a gasification working surface, and performing a series of redox reactions with underground coal under the heating action to generate a series of gases such as methane, hydrogen, carbon monoxide and the like; when the proportion of a 2H gas compound in exhausted gas is measured through a deuterium metabolism spectrum of a gas collection channel opening and an imaging technology instrument, and the proportion of 2H2O is almost 1, it is indicated that the basic reaction of coal on the underground gasification working face is completed, the continuous oil pipe is controlled to retreat through a roller arranged on the ground so as to control the underground fire area to move backwards, and a new gasification working face is formed.

Description

Technical Field

[0001] The present invention belongs to the technical field of underground coal gasification, and in particular, relates to a method for judging the reaction degree of an underground fire zone based on isotope labeling. Background Art

[0002] Underground coal gasification technology is a new mining method for deep coal mining, which has broad development prospects. However, it still has some difficulties to be overcome in some key technical fields, including underground fire zone detection technology. Traditional detection methods mainly include electrical resistance tomography and transient electromagnetic method. However, both methods have problems such as response lag and unclear response to the actual situation of the fire zone, and cannot control the movement of the gas injection point in time according to the combustion situation of the fire zone. Therefore, a method for judging the reaction degree of underground fire zone based on isotope labeling with accurate detection results and timely detection is needed. Summary of the invention

[0003] The purpose of the present invention is to provide a method for determining the reaction degree of underground fire zone based on isotope labeling with accurate and timely detection results. 2 H-labeled 2 H2O and 2 O, make 2 H2O and 2 After O reaches the gasification working face, it undergoes a series of redox reactions with underground coal under the action of heating, generating a series of gases such as methane, hydrogen, and carbon monoxide. The deuterium metabolism spectrum and imaging technology instruments at the gas collection channel mouth measure the content of the discharged gas. 2 H gas compound ratio, 2 When the proportion of H2O is almost 1, it means that the basic reaction of coal in the underground gasification working face is completed. The roller installed on the ground controls the retreat of the continuous oil pipe to control the backward movement of the underground fire zone and form a new gasification working face.

[0004] To achieve the above object, the present invention adopts the following technical solutions: The method for determining the reaction degree of underground fire zone based on isotope labeling comprises the following steps: (1) will be 2 H-labeled 2 H2O same 2 O is injected into the coiled tubing; (2) 2 H2O and 2 After passing through the coal seam through the continuous oil pipe to reach the gasification working face, underground ignition is carried out; (3) 2 H2O and 2 O undergoes a series of redox reactions with underground coal under heating, and the generated gas is discharged through the gas collecting channel; (4) The deuterium metabolism spectrum and imaging technology instrument at the gas collection channel mouth measures the content of deuterium in the exhaust gas. 2 H gas compound ratio; (5) When the instrument at the gas collection channel outlet measures 2 When the proportion of H2O is close to 1, it indicates that the basic reaction of coal in the underground gasification working face is completed. At this time, the roller installed on the ground controls the retreat of the continuous oil pipe to control the backward movement of the underground fire zone and form a new gasification working face.

[0005] In step (2), the chemical reaction includes: ①C+2H2O=2H2+CO2 ②C+H2O=H2+CO ③C+2H2=CH4.

[0006] The gases generated in step (3) include hydrogen, methane, carbon monoxide, carbon dioxide and water vapor. As the reaction proceeds, the content of water vapor gradually increases, while the content of the remaining gases gradually decreases.

[0007] In step (4), the deuterium metabolic spectroscopy and imaging technology instrument at the gas collection channel port uses proton magnetic resonance spectroscopy to identify and analyze the related 2 H concentration of labeled compound.

[0008] After the underground fire zone is moved back to form a new gasification working face in step (5), steps (1) to (5) are continuously repeated until the coal seam is mined.

[0009] The present invention is injected 2 H-labeled 2 H2O and 2 O, make 2 H2O and 2 After O reaches the gasification working face, it undergoes a series of redox reactions with underground coal under the action of heating, generating a series of gases such as methane, hydrogen, and carbon monoxide. The deuterium metabolism spectrum and imaging technology instruments at the gas collection channel mouth measure the content of the discharged gas. 2 H gas compound ratio, 2 When the proportion of H2O is almost 1, it means that the basic reaction of coal in the underground gasification working face is completed. The roller installed on the ground controls the retreat of the continuous oil pipe to control the backward movement of the underground fire zone and form a new gasification working face. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 It is a flow chart of the determination method of the present invention.

[0011] Figure 2It is a structural schematic diagram of underground coal gasification and main chemical reactions in the judgment method of the present invention.

[0012] Figure 3 It is a schematic diagram of the structure of controlling the backward gas injection point in the judgment method of the present invention. DETAILED DESCRIPTION

[0013] The embodiments of the present invention are further described below with reference to the accompanying drawings.

[0014] like Figure 1-3 As shown, the method for determining the reaction degree of underground fire zone based on isotope labeling includes the following steps: (1) will be 2 H-labeled 2 H2O same 2 O is injected into the coiled tubing 2; (2) 2 H2O and 2 After passing through the coal seam 1 through the coiled tubing 2 to reach the gasification working face, underground ignition is performed; (3) 2 H2O and 2 O undergoes a series of redox reactions with underground coal under heating, and the generated gas is discharged through the gas collecting channel 3; (4) The deuterium metabolism spectrum and imaging technology instrument 4 at the gas collection channel mouth measures the content of deuterium in the exhaust gas. 2 H gas compound ratio; (5) When the instrument at the gas collection channel outlet measures 2 When the proportion of H2O is close to 1, it means that the basic reaction of coal in the underground gasification working face is completed. At this time, the roller 5 set on the ground controls the continuous tubing 2 to retreat, thereby controlling the underground fire zone to move backward and forming a new gasification working face. The rotation of the roller 5 set on the ground controls the backward movement of the continuous tubing 2, wherein the continuous tubing 2 is a flexible hose; the continuous tubing is conventionally set and is directly arranged in the gas injection well. Since the continuous tubing 2 directly reaches the gasification working face through the gas injection well, the continuous backward movement of the continuous tubing 2 causes the gas injection point to move backward, thereby controlling the backward movement of the underground fire zone and forming a new gasification working face.

[0015] The present application utilizes the working principle that underground coal gasification requires the injection of water vapor, and selectively injects deuterium ( 2 After a series of redox reactions occur underground, the methane (CH4), hydrogen (H2), and water vapor ( 2 H2O) ratio to determine whether the underground reaction is complete, and then move the gas injection port to control the movement of the gasification working surface. Since water vapor is continuously and excessively injected, the gas at the outlet still contains2 Water vapor marked by H. In addition, the present application is mainly based on the controlled retreat gas injection point technology (CRIP technology), that is, the movement of the gasification working face can be artificially controlled by gas injection using the retreat movement of the gas injection point, thereby realizing effective control of the gasification working face. A gas injection pipe is set in the gasification channel, and the gas injection pipe is continuously or intermittently retreated to realize continuous or intermittent retreat movement of the gas injection point. In this process, the production well is a vertical well, and the injection well is a directional well connected to the production well. An oxygen supply pipe is sent into the directional well, and the oxygen supply pipe directly delivers oxygen and water vapor to the gasification working face. The end of the injection well starts the gasification reaction at the horizontal section in the coal seam 1. When the coal near the reaction chamber is burned out, the injection point is withdrawn to form a new gasification reaction zone. Through this method, it is possible to control the movement of the gas injection point as the gasification working face retreats.

[0016] Due to the complex underground environment, there are various impurities in addition to coal. This method assumes that the underground coal is uniform. In step (2), the chemical reactions in which water vapor mainly participates include: ①C+2H2O=2H2+CO2 ②C+H2O=H2+CO ③C+2H2=CH4.

[0017] The gas generated in step (3) includes hydrogen, methane, carbon monoxide, carbon dioxide and water vapor. Since the injection of water vapor at the gas injection port is continuous, at the beginning of the reaction, the gas content ratio measured at the gas outlet is mainly composed of hydrogen, carbon monoxide, methane and a small amount of water vapor. However, as time goes by, the underground gasification area gradually expands, and the generated hydrogen, carbon monoxide, methane and other gases are also being continuously reduced. At the same time, the proportion of water vapor is increasing. By measuring the proportion of each gas content at the gas outlet, the degree of underground gasification reaction can be judged, so as to prepare for moving the gas injection point in advance. Under normal circumstances, when the underground gasification working surface just starts to burn, the main gas components measured at the gas injection port are hydrogen and methane. However, as the reaction continues, the gasification working surface gradually expands, the content of hydrogen, methane and other gases measured at the gas injection port continues to decrease, and the water vapor content continues to increase. At this time, it should be considered that the underground gasification working surface is constantly expanding and the amount of carbon that can participate in the reaction is constantly decreasing. Based on this, the gas injection point can be moved back to control the movement of the gasification working surface.

[0018] In step (4), the deuterium metabolic spectrum and imaging technology instrument 4 at the gas collection channel port uses proton magnetic resonance spectroscopy to identify and analyze the related 2 H concentration of labeled compound. 2 H has the advantages of being simple, fast and cheap. 2When H reacts and combines with other compounds, it will not change the chemical structure, physical properties, biological characteristics, etc. of the original compounds. 2 The determination of H concentration mainly relies on "deuterium metabolic spectroscopy and imaging technology (DMS / DMI)". The main principle is based on 2 Compounds labeled with different H have different chemical shifts, which can be identified by proton magnetic resonance spectroscopy (MRS). Combined with spatial localization encoding, the related 2 H concentration of labeled compound.

[0019] After the underground fire zone is moved back to form a new gasification working face in step (5), steps (1) to (5) are continuously repeated until the coal seam 1 is mined.

[0020] The present invention is injected 2 H-labeled 2 H2O and 2 O, make 2 H2O and 2 After O reaches the gasification working face, it undergoes a series of redox reactions with underground coal under the action of heating, generating a series of gases such as methane, hydrogen, and carbon monoxide. The deuterium metabolism spectrum and imaging technology instrument 4 at the gas collection channel mouth measures the content of the discharged gas. 2 H gas compound ratio, 2 When the proportion of H2O is almost 1, it indicates that the basic reaction of coal in the underground gasification working face is completed. The roller 5 set on the ground controls the continuous oil pipe 2 to retreat, thereby controlling the underground fire zone to move backward and forming a new gasification working face.

[0021] The above embodiments are only used to illustrate rather than limit the technical solutions of the present invention. Although the present invention is described in detail with reference to the above embodiments, those skilled in the art should understand that the present invention can still be modified or replaced by equivalents. Any modification or partial replacement that does not depart from the spirit and scope of the present invention should be included in the scope of the claims of the present invention.

Claims

1. A method for determining the reaction degree of underground fire zones based on isotope labeling, characterized in that: The steps include: (1) will be 2 H-labeled 2 H2O same 2 O is injected into the coiled tubing; (2) 2 H2O and 2 After passing through the coal seam through the continuous oil pipe to reach the gasification working face, underground ignition is carried out; (3) 2 H2O and 2 O undergoes a series of redox reactions with underground coal under heating, and the generated gas is discharged through the gas collecting channel; (4) The deuterium metabolism spectrum and imaging technology instrument at the gas collection channel mouth measures the content of deuterium in the exhaust gas. 2 H gas compound ratio; (5) When the instrument at the gas collection channel outlet measures 2 When the proportion of H2O is close to 1, it means that the basic reaction of coal in the underground gasification working face is completed. At this time, the roller set on the ground controls the retreat of the continuous oil pipe to control the backward movement of the underground fire zone and form a new gasification working face.

2. The method for determining the reaction degree of underground fire zone based on isotope labeling according to claim 1, characterized in that: In step (2), the chemical reaction includes: ①C+2H2O=2H2+CO2 ②C+H2O=H2+CO ③C+2H2=CH4.

3. The method for determining the reaction degree of underground fire zone based on isotope labeling according to claim 2, characterized in that: The gases generated in step (3) include hydrogen, methane, carbon monoxide, carbon dioxide and water vapor. As the reaction proceeds, the content of water vapor gradually increases, while the content of the remaining gases gradually decreases.

4. The method for determining the reaction degree of underground fire zone based on isotope labeling according to claim 3, characterized in that: In step (4), the deuterium metabolic spectroscopy and imaging technology instrument at the gas collection channel port uses proton magnetic resonance spectroscopy to identify and analyze the related 2 H concentration of labeled compound.

5. The method for determining the reaction degree of underground fire zone based on isotope labeling according to claim 4 is characterized in that: After the underground fire zone is moved back to form a new gasification working face in step (5), steps (1) to (5) are continuously repeated until the coal seam is mined.

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