A method for coordinated treatment of abandoned oil wells and hydrogen sulfide wells in coal mining areas

Abstract

The present invention belongs to the field of coal mine safety, and relates to the prevention and control of hydrogen sulfide disasters in mines, and in particular to a method for coordinated upper and lower control of hydrogen sulfide wells in abandoned oil wells in coal mine areas. The method firstly performs advance control by injecting alkaline absorption liquid in the ground area through the abandoned oil well drilling holes on the ground, and then performs local area pressure injection of alkaline absorption liquid control by drilling holes in the coal seam during the construction of underground mining tunnels. Finally, during the mining of the working face, short-hole alkaline absorption liquid supplementary control is performed by drilling holes in the coal wall construction direction and in the layer, and the effect is tested, so as to realize the advance, efficient and refined control of hydrogen sulfide in the coal seam in the area affected by the abandoned oil well.

Description

Technical Field

[0001] The invention belongs to the field of coal mine safety, relates to the prevention and control of hydrogen sulfide disasters in mines, and in particular to a method for coordinated management of hydrogen sulfide wells in abandoned oil wells in coal mine areas. Background Art

[0002] In many sedimentary basins at home and abroad, there are many examples of the coexistence and even symbiosis of coal, oil and gas. In coal mining areas where resources are superimposed, due to the early development or superimposed exploitation of oil and gas resources, a large number of abandoned oil and gas wells left over from the early exploitation of oil and gas have caused great difficulties for the subsequent exploitation of coal resources. Abandoned oil wells exposed by the mining face of the mine are at risk of high-pressure oil and gas gushing or gushing out. When mining activities are carried out in oil and gas infiltration areas, there are major safety hazards such as serious over-limit of gas and hydrogen sulfide. Hydrogen sulfide is the main toxic and harmful gas in the process of oil and gas well field exploitation, and it is also the main toxic and harmful gas in coal mining. The hazards of hydrogen sulfide mainly cause coughing in contacts, irritation of the eyes, causing severe pain and redness and swelling. In severe cases, it can cause contacts to lose consciousness, respiratory arrest, death, etc. In addition, it is also explosive and corrosive to underground coal mine equipment and monitoring facilities. Serious hazards of hydrogen sulfide in coal mines.

[0003] At present, the main prevention and control measures for hydrogen sulfide disasters in coal mines include increasing the ventilation volume of mines to dilute, extracting hydrogen sulfide from coal bodies, spraying alkaline solutions, and pre-injecting alkaline absorption liquid into coal bodies for absorption. The control effects of increasing air volume and coal body extraction measures are limited, and the spraying of alkaline solution control measures are passive measures, and it is difficult to fundamentally solve the problem. The coal body pre-injection of alkaline absorption liquid control measures actively neutralizes and absorbs hydrogen sulfide in the coal body before mining, which can avoid the passivity of hydrogen sulfide control work. The conventional method is to inject alkaline absorption liquid into the coal body through the mining tunnel, but due to the influence of coal body hardness, coal seam water injection ability, etc., the best effect is often not achieved. In particular, for the control of hydrogen sulfide in mining faces affected by abandoned oil wells in coal mining areas, it is urgent to seek an efficient control method to control hydrogen sulfide before mining at the working face to avoid the large-scale outburst of hydrogen sulfide affected by mining and ensure safe production in coal mining areas. Summary of the invention

[0004] In view of this, the purpose of the present invention is to provide a method for coordinated management of abandoned oil wells and hydrogen sulfide wells in coal mining areas, so as to solve the problem that coal mining in coal and oil resource co-storage areas is affected by hydrogen sulfide disasters.

[0005] To achieve the above object, the present invention provides the following technical solution: a method for coordinated treatment of hydrogen sulfide wells in abandoned oil wells in coal mining areas, comprising the following steps:

[0006] S1, advance treatment by injecting alkaline absorption liquid into the ground area;

[0007] S11, collect and analyze abandoned oil well data, determine the oil well type, completion method, well structure, abandonment situation, coal-bearing strata, specific location and coordinate parameters, and formulate a construction plan for ground injection of alkaline absorption liquid;

[0008] S12, find the specific location of the abandoned oil well and excavate the oil well entrance. According to the situation of the oil well drilling hole penetrating the coal-bearing strata, make the bottom platform when the hole is 80 to 100 meters below the bottom plate of the lowest mineable coal seam;

[0009] S13, according to the coal penetration situation of the oil well, the alkaline absorption liquid process is implemented in each coal seam section by section, and after the fracturing is completed, the oil well borehole is fully plugged;

[0010] S14, monitoring the impact range of fracturing by means of microseismic monitoring fracture monitoring technology;

[0011] S2, comprehensive analysis of underground monitoring to delineate local areas;

[0012] During the excavation of underground mining tunnels, the hydrogen sulfide outburst is monitored and test holes are constructed. After the test holes are completed, the hydrogen sulfide concentration in the holes is measured after plugging for 48 hours to determine whether there is hydrogen sulfide gas in the holes. Combined with the surface monitoring of the fracturing influence range, the underground alkaline absorption liquid injection drilling implementation area is comprehensively delineated;

[0013] S3, injection of alkaline absorption liquid for local area treatment in the underground well;

[0014] In the designated underground alkaline absorption liquid injection drilling implementation area, the alkaline absorption liquid injection drilling is constructed along the coal seam inclination through the return air lane or the transport lane, and the alkaline absorption liquid is injected into the coal seam through the coal seam pre-injection alkaline absorption liquid implementation system. At the same time, it is determined whether to repeat the injection of alkaline absorption liquid according to the treatment effect of the drilling hole injection alkaline absorption liquid;

[0015] S4, supplementary treatment during the mining period of the working face;

[0016] During the mining period of the working face, according to the situation of hydrogen sulfide outburst caused by mining, holes are drilled along the direction of the coal seam through the coal wall of the working face, and alkaline absorption liquid is injected locally for supplementary treatment to further reduce the hydrogen sulfide content in the coal body.

[0017] Optionally, in the injection alkaline absorption liquid treatment process of step S13, if the distance between the mineable coal seams is within 10m, joint injection is carried out at one time.

[0018] Optionally, in step S2, the detection boreholes are constructed along the inclination of the coal seam through the return air lane or the transport lane, and are arranged on both sides with the oil well borehole as the center, and the detection borehole strike spacing is 30 to 50 m.

[0019] Optionally, during the excavation of underground mining tunnels, one or a combination of control measures such as spraying alkaline absorption liquid, extraction and purification with dust removal fans, injection of alkaline absorption liquid, and ventilation dilution may be adopted according to the situation of hydrogen sulfide outburst during excavation.

[0020] Optionally, in step S3, the alkaline absorption liquid is injected into the drilling holes along the dip of the coal seam, with a designed spacing of 10 to 15 m, an injection pressure of 20 to 30 MPa, and an injection pump flow rate of 150 to 300 L / min.

[0021] Optionally, in step S3, the test method for the treatment effect of the borehole injection of alkaline absorption liquid is: after the completion of the drilling construction, the borehole hydrogen sulfide volume fraction is measured as C1 after plugging for 48 hours, and the borehole hydrogen sulfide volume fraction is measured as C2 after plugging for 48 hours after the completion of the alkali injection, then the alkali injection treatment efficiency of hydrogen sulfide is A = (C1-C2) / C1×100%;

[0022] If A≥90% and C2≤50ppm, there is no need to repeat the alkali injection. Otherwise, it is necessary to repeat the alkali paper injection until the test result meets the standard.

[0023] Optionally, if the volume fraction of hydrogen sulfide in the borehole of the hydrogen sulfide-containing coal seam is measured to be lower than 50 ppm 48 hours after the borehole is sealed, the hydrogen sulfide emitted during mining can be solved by spraying and ventilation dilution measures.

[0024] Optionally, in step S4, the condition for implementing the short-hole alkaline absorption liquid injection supplementary treatment process is: measuring the hydrogen sulfide volume fraction C3 before and after the coal mining machine and support spray are turned on during the working face mining, and the hydrogen sulfide treatment efficiency of the coal mining machine and support spray is B = (C3-C4) / C3×100%; if B≥70% and C4≤20ppm, or C3≤50ppm, local supplementary measures are not implemented, otherwise, local supplementary measures are required.

[0025] Optionally, the length of the strike-bedding borehole shall not be less than 3 times the daily advancement distance of the working face and shall not be less than 20m.

[0026] The beneficial effects of the present invention are as follows: the present invention provides a method for coordinated treatment of hydrogen sulfide in abandoned oil wells in coal mining areas, by making full use of the ground abandoned oil well drilling holes for ground fracturing advance injection, and then combining the division of underground affected areas and effect inspection to carry out regional drilling and injection supplementary measures, thereby achieving advanced, efficient and refined treatment of hydrogen sulfide in coal seams in the abandoned oil well affected areas

[0027] Other advantages, objectives and features of the present invention will be described in the following description to some extent, and to some extent, will be obvious to those skilled in the art based on the following examination and study, or can be taught from the practice of the present invention. The objectives and other advantages of the present invention can be realized and obtained through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention will be described in detail below in conjunction with the accompanying drawings, wherein:

[0029] Figure 1 This is a flow chart of the method for coordinated treatment of hydrogen sulfide wells in abandoned oil wells in coal mining areas according to the present invention;

[0030] Figure 2 It is a plan view of the drilling arrangement of the up-and-down well coordinated treatment method of the present invention;

[0031] Figure 3 It is a cross-sectional arrangement diagram of the drilling holes of the up-and-down well coordinated management method of the present invention.

[0032] Figure numerals: mining tunnel 1, detection borehole 2, oil well borehole 3, alkaline absorption liquid injection borehole 4, strike-beam borehole 5, coal seam 6. DETAILED DESCRIPTION

[0033] The following describes the embodiments of the present invention by specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the following embodiments only illustrate the basic concept of the present invention in a schematic manner, and the following embodiments and features in the embodiments can be combined with each other without conflict.

[0034] Among them, the drawings are only used for illustrative explanations, and they only represent schematic diagrams rather than actual pictures, and should not be understood as limitations on the present invention. In order to better illustrate the embodiments of the present invention, some parts of the drawings may be omitted, enlarged or reduced, and do not represent the size of actual products. For those skilled in the art, it is understandable that some well-known structures and their descriptions in the drawings may be omitted.

[0035] The same or similar numbers in the drawings of the embodiments of the present invention correspond to the same or similar parts; in the description of the present invention, it should be understood that if the terms "upper", "lower", "left", "right", "front", "rear", etc. indicate the orientation or position relationship, they are based on the orientation or position relationship shown in the drawings, which is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation. Therefore, the terms describing the position relationship in the drawings are only used for illustrative purposes and cannot be understood as limiting the present invention. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.

[0036] See also Figure 1 to Figure 3 , which is a method for coordinated treatment of hydrogen sulfide in abandoned oil wells in coal mining areas. First, alkaline absorption liquid is injected in the ground area through the abandoned oil well drilling hole 3 for advanced treatment, and then alkaline absorption liquid is injected in the local area through the drilling hole in the coal seam constructed in the underground mining tunnel 1. Finally, during the mining of the working face, short-hole alkaline absorption liquid is injected in the drilling hole 5 in the direction of the coal wall construction to supplement treatment, and the effect is tested, so as to achieve coordinated treatment of hydrogen sulfide in the coal seam in the area affected by abandoned oil wells in the coal mining area from the regional to the local wells; specifically, the following steps are included:

[0037] 1) Advanced treatment of ground area by injection of alkaline absorption liquid; the main process flow is:

[0038] a. Collect and analyze abandoned oil well data, determine the oil well type, completion method, well structure, abandonment, coal-bearing strata, specific location and coordinates, and formulate a construction plan for ground injection of alkaline absorption liquid;

[0039] b. Find the specific location of the abandoned oil well and excavate the oil well entrance. According to the situation of the oil well drilling hole 3 penetrating the coal-bearing stratum, make the bottom platform when the hole is 80 to 100 meters below the bottom plate of the lowest mineable coal seam;

[0040] c. According to the coal penetration situation of the oil well, the alkaline absorption liquid process is implemented in each coal seam section by section, and after the fracturing is completed, the oil well borehole 3 is fully plugged;

[0041] In this embodiment, the ground injection alkaline absorption liquid treatment process is used. If the distance between the mineable coal seams is within 10m, joint injection is performed at one time. In addition, the fracture influence range needs to be monitored by microseismic monitoring and other fracture monitoring techniques.

[0042] 2) Comprehensive analysis of underground monitoring to delineate local areas; that is, during the excavation of underground mining tunnel 1, the hydrogen sulfide outflow is monitored, and the inspection borehole 2 is constructed to determine whether there is hydrogen sulfide gas in the borehole. Combined with the surface monitoring of the fracturing influence range, the implementation area of ​​underground alkaline absorption liquid injection borehole 4 is comprehensively delineated;

[0043] In this embodiment, the detection borehole 2 is constructed along the coal seam 6 through the return air lane or the transport lane, and is arranged on both sides with the oil well borehole 3 as the center, and the strike spacing of the detection borehole 2 is 30 to 50 meters; after the construction of the detection borehole 2 is completed, the hydrogen sulfide concentration of the borehole is measured after plugging for 48 hours;

[0044] In this embodiment, during the excavation of the underground mining tunnel 1, according to the hydrogen sulfide gushing during the excavation, one or more of the following treatment measures are adopted: spraying alkaline absorption liquid, extracting and purifying with a dust removal fan, injecting alkaline absorption liquid, ventilation dilution, etc.;

[0045] 3) Alkaline absorption liquid injection treatment in local areas underground; that is, in the designated area for the implementation of alkaline absorption liquid injection drilling hole 4 underground, the alkaline absorption liquid injection drilling hole 4 is constructed along the coal seam 6 through the return air lane or the transport lane, and the alkaline absorption liquid is injected into the coal seam 6 through the coal seam 6 pre-injection alkaline absorption liquid implementation system, and at the same time, it is determined whether to repeat the injection of alkaline absorption liquid according to the treatment effect of the drilling hole injection alkaline absorption liquid;

[0046] In this embodiment, the alkaline absorption liquid injection drilling hole 4 is constructed along the coal seam 6, the design spacing is 10-15m, the injection pressure is 20-30MPa, the injection pump flow rate is 150-300L / min, and it is adjusted according to the actual on-site investigation results;

[0047] In this embodiment, the test method for the treatment effect of the alkaline absorption liquid injection into the borehole is as follows: after the completion of the drilling construction, the borehole hydrogen sulfide volume fraction is measured as C1 after the plugging is completed for 48 hours, and the borehole hydrogen sulfide volume fraction is measured as C2 after the plugging is completed for 48 hours, then the alkali injection treatment efficiency of hydrogen sulfide is A=(C1-C2) / C1×100%; if A≥90% and C2≤50ppm (according to field experience, the borehole hydrogen sulfide volume fraction is measured to be lower than 50ppm 48 hours after the plugging of the borehole of the hydrogen sulfide-containing coal seam, then the hydrogen sulfide gushing out during the mining period can be solved by spraying and ventilation dilution measures), then there is no need to repeat the alkali injection, otherwise it is necessary to repeat the alkali paper injection until the test effect meets the standard;

[0048] 4) Supplementary treatment during the mining of the working face; that is, during the mining of the working face, according to the hydrogen sulfide outburst situation, the working face coal wall is drilled along the direction of the coal seam 6 (the mining direction of the working face) to carry out local injection of alkaline absorption liquid for supplementary treatment, so as to further reduce the hydrogen sulfide content in the coal body;

[0049] In this embodiment, the condition for implementing the short-hole alkaline absorption liquid injection supplementary treatment process is: measuring the hydrogen sulfide volume fraction C3 before the coal mining machine and support spray are turned on and the hydrogen sulfide volume fraction C4 after the spray is turned on during the working face mining, then the coal mining machine and support spray hydrogen sulfide treatment efficiency is B = (C3-C4) / C3×100%; if B≥70% and C4≤20ppm, or C3≤50ppm, then local supplementary measures are not implemented, otherwise, local supplementary measures need to be implemented.

[0050] In this embodiment, the length of the borehole along the strike direction is not less than 3 times the daily advancement distance of the working face and is not less than 20m.

[0051] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution, which should be included in the scope of the claims of the present invention.

Claims

1. A method for coordinated treatment of hydrogen sulfide wells in abandoned oil wells in coal mining areas, characterized in that: The following steps are involved: S1, advance treatment by injecting alkaline absorption liquid into the ground area; S11, collect and analyze abandoned oil well data, determine the oil well type, completion method, well structure, abandonment situation, coal-bearing strata crossed, specific location, and formulate a construction plan for ground injection of alkaline absorption liquid; S12, find the specific location of the abandoned oil well and excavate the oil well entrance. According to the situation of the oil well drilling hole penetrating the coal-bearing strata, make the bottom platform when the hole is 80 to 100 meters below the bottom plate of the lowest mineable coal seam; S13, according to the coal penetration situation of the oil well, the alkaline absorption liquid process is implemented in each coal seam section by section, and after the fracturing is completed, the oil well borehole is fully plugged; S14, monitoring the impact range of fracturing by means of microseismic monitoring fracture monitoring technology; S2, comprehensive analysis of underground monitoring to delineate local areas; During the excavation of underground mining tunnels, the hydrogen sulfide outburst is monitored and test holes are constructed. After the test holes are completed, the hydrogen sulfide concentration in the holes is measured after plugging for 48 hours to determine whether there is hydrogen sulfide gas in the holes. Combined with the surface monitoring of the fracturing influence range, the underground alkaline absorption liquid injection drilling implementation area is comprehensively delineated; S3, injection of alkaline absorption liquid for local area treatment; In the designated underground alkaline absorption liquid injection drilling implementation area, the alkaline absorption liquid injection drilling is constructed along the coal seam inclination through the return air lane or the transport lane, and the alkaline absorption liquid is injected into the coal seam through the coal seam pre-injection alkaline absorption liquid implementation system. At the same time, it is determined whether to repeat the injection of alkaline absorption liquid according to the treatment effect of the drilling hole injection alkaline absorption liquid; S4, supplementary treatment during the mining period of the working face; During the mining period of the working face, according to the situation of hydrogen sulfide outburst caused by mining, holes are drilled along the direction of the coal seam through the coal wall of the working face, and alkaline absorption liquid is injected locally for supplementary treatment to further reduce the hydrogen sulfide content in the coal body.

2. The method for coordinated treatment of hydrogen sulfide wells in abandoned oil wells in coal mining areas according to claim 1, characterized in that: In the injection alkaline absorption liquid treatment process of step S13, if the distance between the mineable coal seams is within 10m, joint injection is carried out at one time.

3. The method for coordinated treatment of hydrogen sulfide wells in abandoned oil wells in coal mining areas according to claim 1, characterized in that: In step S2, the detection boreholes are constructed along the inclination of the coal seam through the return air tunnel or the transport tunnel, and are arranged on both sides with the oil well borehole as the center. The detection borehole strike spacing is 30 to 50 m.

4. The method for coordinated treatment of hydrogen sulfide wells in abandoned oil wells in coal mining areas according to claim 1, characterized in that: During the excavation of underground mining tunnels, according to the situation of hydrogen sulfide outburst during excavation, one or a combination of control measures such as spraying alkaline absorption liquid, extraction and purification by dust removal fans, injection of alkaline absorption liquid, and ventilation dilution are adopted.

5. The method for coordinated treatment of hydrogen sulfide wells in abandoned oil wells in coal mining areas according to claim 1, characterized in that: In step S3, the alkaline absorption liquid is injected into the drilling holes along the coal seam inclination, with a designed spacing of 10 to 15 m, an injection pressure of 20 to 30 MPa, and an injection pump flow rate of 150 to 300 L / min.

6. The method for coordinated treatment of hydrogen sulfide wells in abandoned oil wells in coal mining areas according to claim 1, characterized in that: In step S3, the test method for the treatment effect of drilling hole injection of alkaline absorption liquid is as follows: after the completion of drilling construction, the borehole hydrogen sulfide volume fraction is measured by plugging for 48 hours, which is C1; after the completion of alkali injection, the borehole hydrogen sulfide volume fraction is measured by plugging for 48 hours, which is C2. The efficiency of alkali injection for hydrogen sulfide treatment is A=(C1-C2) / C1×100%; If A≥90% and C2≤50ppm, there is no need to repeat the alkali injection. Otherwise, it is necessary to repeat the alkali paper injection until the test result meets the standard.

7. The method for coordinated treatment of hydrogen sulfide wells in abandoned oil wells in coal mining areas according to claim 6, characterized in that: If the volume fraction of hydrogen sulfide in the borehole of a hydrogen sulfide-containing coal seam is measured to be lower than 50 ppm 48 hours after the borehole is sealed, the hydrogen sulfide gushing out during mining will be solved by spraying and ventilation dilution measures.

8. The method for coordinated treatment of hydrogen sulfide wells in abandoned oil wells in coal mining areas according to claim 1, characterized in that: In step S4, the condition for implementing the short-hole alkaline absorption liquid supplementary treatment process is: determine the hydrogen sulfide volume fraction C3 before the coal mining machine and support spray are turned on and the hydrogen sulfide volume fraction C4 after they are turned on during the working face mining period, then the coal mining machine and support spray hydrogen sulfide treatment efficiency is B = (C3-C4) / C3×100%; if B≥70% and C4≤20ppm, or C3≤50ppm, then local supplementary measures will not be implemented, otherwise, local supplementary measures need to be implemented.

9. The method for coordinated treatment of hydrogen sulfide wells in abandoned oil wells in coal mining areas according to claim 8, characterized in that: The length of the borehole drilled along the strike direction shall not be less than 3 times the daily advancement distance of the working face and shall not be less than 20m.

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