About the author: Xu Wenjun, male, born in 1962, is an engineer. Mainly engaged in coalbed methane exploration, development and scientific research management, address: No.88, Anwai Street, Dongcheng District, Beijing (1001), telephone: (0 10) 64267069, and email: Xu Wenjun 0100.
(China United Coalbed Methane Co., Ltd. Beijing 1000 1 1)
The State Council Guo Ban Fa [2006] No.47 "Several Opinions on Accelerating the Extraction and Utilization of Coalbed Methane (Coal Mine Gas)" and Guo Tu Zi Fa [2007] No.96 "Notice on Strengthening the Management of Comprehensive Exploration and Exploitation of Coal and Coalbed Methane Resources" require "gas production first, then coal mining", making overall consideration and coordinating the contradiction between gas production and coal mining, but there are many technical and conceptual problems in actual implementation. According to the different stages of coal production and construction, as well as the actual situation of production, infrastructure, planning and other mine fields, the method of combining different coalbed methane mining methods with coal production and construction is adopted to explore and solve the problems of overlapping resources and crossing time and space. In view of the existing problems, this paper puts forward guidance and coordination from the aspects of national administration, policy adjustment and technical standard requirements to promote its development.
Keywords: coordinated development of coalbed methane and coal
Coalbed methane and cooling are necessary conditions for harmonious development.
Zan Xu is a man.
(China United Coalbed Methane Co., Ltd., Beijing 100083, China)
In 2007, Guo Tu Zi No.96 issued the Notice on Strengthening the Comprehensive Exploration and Management of Coal and Coalbed Methane Resources, requiring overall planning, gas production first, and coal mining later. The purpose is to coordinate the contradiction between gas and coal mining. But in fact, there are many technical problems and conceptual misunderstandings in the implementation. Aiming at different stages of coal mining, such as production, capital construction and planning, this paper combines different coal mining methods and production and construction methods to solve the problems of regional overlap and space-time intersection of resources.
Keywords: coalbed methane; Coal; Coordination; develop
Coalbed methane is an unconventional natural gas, which is mainly adsorbed in coal seams and stored with coal. It is a new clean energy and chemical raw material with high quality and high efficiency, and it is one of the important alternative energy sources for China's sustainable economic development and low-carbon economy in 2 1 century. At the same time, it is also the main component of mine gas, the harmful gas in the process of coal mining and the root of coal mine gas disaster.
Coalbed methane and coal belong to two independent mineral resources, which belong to the mineral industry with fluid and solid physical properties respectively. According to the characteristics of accompanying, co-storing and separate mining, aiming at the phenomenon of overlapping of coalbed methane and coal mining rights and disorderly competition among enterprises at present, the guiding spirit of the State Council Guofa [2006] No.47 "Several Opinions on Accelerating the Extraction and Utilization of Coalbed Methane" and Guo Ban Fa [2007] No.96 "Notice on Strengthening the Management of Comprehensive Exploration and Exploitation of Coal and Coalbed Methane Resources" and the Basic Requirements for Coal Mine Gas Extraction issued by the State Administration of Work Safety require that Therefore, combined with the current actual situation and future development trend, it is necessary to establish a mechanism and technical system for coordinated development of coalbed methane and coal.
1 Present situation and necessity of coal and coalbed methane development
1. 1 development status of coal and coalbed methane
China is a country rich in coal resources (about 5 trillion t). Since 1998, China's coal production and consumption have been ranked first in the world. In 20 10, the cumulative raw coal output in China reached 3.2 billion tons, accounting for 79% and 68% of the total primary energy production and consumption in China respectively. In China, a large amount of methane gas is discharged into the atmosphere every year due to coal mining (according to the United Nations survey report, China's methane emission reaches 65.438+094 billion m3, accounting for about 654.38+0/3 of the global methane emission), which is the main source of air pollution and greenhouse gas emission. At present, high gas mines and coal and gas outburst mines account for about 40% in China's coal mines, and nearly 70% of the deaths in coal mine safety accidents are caused by gas accidents, which poses a great threat to the efficient and safe production of coal mines in China. In 20 10, there were 2433 coal mine safety accidents 1403, and the death rate per million tons dropped to 0.749. Compared with developed countries in international coal mining, the situation of coal mine gas prevention and control in China is still grim (see table 1).
Table 1 Comprehensive Statistics of Coal and Coalbed Methane Production and Coal Mine Deaths in China over the Years
Source: According to statistics published by National Energy Administration and State Administration of Coal Mine Safety.
China is rich in coalbed methane resources. According to the results of a new round of national oil and gas resources evaluation, the gas-bearing area of shallow coal seams with a depth of 2000 meters in China is 375,000 km2, and the total coalbed methane resources are 36.8 trillion m3, which is equivalent to the conventional natural gas resources on land in China. Up to now, more than 5,400 CBM wells have been built in China, including 3,653 CBM development and production wells (including 3,590 vertical wells and 63 horizontal wells). In 20 10, the national coalbed methane output reached 8.53 billion m3, including 6.963 billion m3 extracted from underground coal mines and 0.567 billion m3 developed on the ground.
1.2 Necessity of coal and coalbed methane development
Energy development is the basic industry of national economy, which plays a very important role in promoting and ensuring sustained, rapid and healthy economic development. At present, coal is the main energy source in China, which occupies a large proportion in the consumption structure. With the rapid development of China's economy, the demand for various energy sources is increasing, but coal will still occupy the most important position in China's energy structure. Developing coalbed methane can increase the supply of clean energy and improve China's current energy consumption structure; Effectively reduce the content of coalbed methane in coal seam, fundamentally control and eliminate mine gas disasters, improve the guarantee degree of coal mine safety production and the economic benefits of coal enterprises; Reduce methane emission from coal mines and effectively alleviate the greenhouse effect; It is the basic guarantee for realizing the sustainable development of resources, environment and social benefits, coping with the future global low-carbon economy and realizing the harmonious development of economic and social development and ecological environment.
According to the overall energy demand of China, the Twelfth Five-Year Plan of National Coalbed Methane compiled by the National Energy Administration puts forward the goal and task of increasing the proven reserves of coalbed methane by 654.38+0.8 billion m3, realizing the production scale of 654.38+0.8 billion m3 per year, and guiding the development direction of coalbed methane industry.
Table 2 List of total energy consumption and its composition in China
Source: Statistical Yearbook of China over the years, Statistical Bulletin of National Economic and Social Development in 2009.
To sum up, the development of coal and coalbed methane will be an important part of China's energy industry in the future. It is of great significance for China's energy industry and national economic development to organically combine coal mining with coalbed methane development and realize the coordinated development of coal and coalbed methane resources.
2 the relationship between coal and coalbed methane development
2. 1 Relationship between natural attributes and mineral rights
Coal and coalbed methane are two mineral resources with different properties, which coexist and store together. Their intuitive substances are independent and closely related. According to its occurrence form and development mode, through the technology of "gas production first, then coal mining" and coordinated development of coal and coalbed methane, gas production and coal mining are combined to achieve balanced and reasonable development, achieve mutual benefit and improve the comprehensive benefits of enterprises.
China's "Mineral Resources Law" and "Relevant Provisions on the Registration and Management of Mineral Resources Exploration Blocks" divide coal and coalbed methane into two independent mineral resources management with different physical properties (solid and fluid). As an unconventional natural gas in the series of natural gas resources, coalbed methane is a strategic oil and gas resource managed at the national level, and the mineral rights are subject to the first-level approval and registration management of the Ministry of Land and Resources. Coal is a general solid energy mineral resource, which is approved and registered by the Ministry of Land and Resources and the competent departments of Geology and Mineral Resources of the people's governments of provinces, autonomous regions and municipalities directly under the Central Government according to the resource management authority, with an area of 30km2. Due to the division and management of mining rights, mining rights overlap, and the exploration and development areas of coal and coalbed methane intersect in time and space.
2.2 Relevant requirements of national industry management policies
The State Council Guofa [2006] No.47 Document "Several Opinions on Accelerating the Extraction and Utilization of Coalbed Methane (Coal Mine Gas)" requires that the policy of "gas extraction first, then coal mining" should be implemented in high gas coal mine areas. In high gas mines with suitable conditions, coal mining can only be carried out when the gas content in the coal mine is reduced below the prescribed standard, and coal and coalbed methane can be rationally developed according to the development procedure of "gas mining first, then coal mining".
Document No.96 [2007] of the Ministry of Land and Resources "Notice on Strengthening the Management of Comprehensive Exploration and Exploitation of Coal and Coalbed Methane Resources" requires that comprehensive exploration, evaluation and recycling of resources should be adhered to in the process of resource exploration; According to the actual situation, strengthen resource management and properly solve the problem of overlapping mining rights; According to the economic and reasonable resource exploration and development procedures, the management mechanism of coordinated development of coal and coalbed methane will be further improved.
The Basic Requirements for Coal Mine Gas Drainage issued by the State Administration of Work Safety stipulates that coal mines that exceed the initial outburst depth, gas content or gas pressure of coal seams must be pre-drained in advance.
2.3 technical system for coordinated development of coal and coalbed methane
Judging from the occurrence form and development mode, coal and coalbed methane coexist, share storage and separate mining. At present, it is necessary to explore the coordination of coalbed methane ground development, mine gas drainage and coal mining in coal mining areas, make overall planning in time and space, and rationally arrange coalbed methane drainage methods in undeveloped areas, mining areas, mined-out areas, abandoned mines and other coal mines, so as to form a technical system of coalbed methane ground development wells+mine gas drainage wells+mining area wells+mined-out areas wells+abandoned mine wells, and form a comprehensive development model of coal and coalbed methane.
Through the coal mine three-dimensional drainage method combining ground drilling of coalbed methane, long drilling along coal seam underground and goaf drainage, the "first pumping and then mining" of coal seam is realized. In time, the ground extraction of coalbed methane is coordinated with the coal production process in the mine; Spatially, the layout of ground coalbed methane wells is coordinated with the mining face; Functionally, surface CBM wells can be used for geological exploration, pre-mining pumping, mid-mining pumping and post-mining pumping. And coordinate with the coalfield geological exploration, coal mine capital construction, mine gas control and coal mine production convergence of coal enterprises, realize the rational exploitation of coal and coalbed methane and the comprehensive control of mine gas, and better serve coal mine production and safety.
3. The main problems at present
(1) Due to the disunity of mineral rights management, the resources in different regions overlap, and the development of coal and coalbed methane resources crosses in time and space, which leads to disorderly competition among different enterprises.
(2) The development of coal and coalbed methane lacks a unified coordination mechanism and technical system. Although the document issued by the Ministry of Land and Resources (Guo Tu Zi Fa [2007] No.96) requires "gas production first, then coal mining", overall planning and coordination of the contradiction between gas production and coal mining, there are many technical problems and misunderstandings in actual implementation.
(3) The development between coal production and coalbed methane development is not harmonious. The characteristics of the industry and the nature of enterprises determine that coal and coalbed methane are independently mined, and the development procedures, time and space cannot be coordinated. Coalbed methane resources are stored in coal seams, and coal mining and coalbed methane development will inevitably interact. On the one hand, the development and utilization of coalbed methane is imperative; On the other hand, coal is the most important primary energy composition in China, and its output must maintain sustained growth; Therefore, it is very important for the healthy development of coal and coalbed methane industry to establish a new mode of coordinated development of coal and coalbed methane.
4 Measures and policy recommendations
(1) It is suggested that the national mineral resources management department should manage the mineral rights of coal and coalbed methane in a unified way, strengthen the management order of the two mineral rights, strengthen the information exchange between them, and coordinate them in a unified way to avoid the overlapping of mineral rights in time and space and in regional scope. Standardize the exploration and development procedures, and comprehensively develop and utilize large-scale coalbed methane fields in accordance with the unified energy integration development plan. At present, in the overlapping areas of mining rights in coal mining areas, the main body of coal and coalbed methane resources development is reasonably divided, and coal mining enterprises are the main body of coalbed methane development in the coal production convergence deployment area within five years; In areas where coal production has been deployed for five years, the development of coalbed methane is mainly based on specialized coalbed methane enterprises; Encouraging coal and coalbed methane enterprises to complement each other and jointly develop can effectively solve the problem of overlapping mining rights, ensure the safety of coal mining, realize the benign operation of coalbed methane and coal industry, and achieve the effect of mutual benefit and win-win.
(2) Implement the national policy of "gas production first, then coal mining", further promulgate the detailed rules for coordinated development of relevant resources, and solve the problem of coordinated development of coal and coalbed methane industry from the mechanism and system. According to the spirit of Document No.47 [2006] issued by the State Council and Document No.96 [2007] issued by the Ministry of Land and Resources, the management procedures for exploration and development of coal and coalbed methane resources are established, and the comprehensive exploration, coordinated development and economic and reasonable exploration and development mode of energy and mineral resources are improved.
(3) Develop rationally according to the principle of "gas production first, then coal mining", and coordinate the development procedures, methods and technical issues of coal and coalbed methane. According to the different stages of coal production and construction, as well as the actual situation of production, infrastructure, planning and other mine fields, different coalbed methane mining methods are combined with coal production and construction.
Table 3 Mining Methods and Development Years of CBM in Different Minefields
(4) In the field of coal production mines, for high-gas mines and coal and gas outburst mines with CBM surface development conditions, the CBM surface development method is given priority to carry out CBM surface drainage and comprehensive gas control. According to the State Administration of Work Safety's Basic Requirements for Coal Mine Gas Drainage, (1 003/t.d) high gas mines with absolute gas emission ≥40m3/min or relative gas emission ≥ 65438+1100m3/t.d; (2) Mining coal and gas outburst mines with dangerous coal seams; (3) Where the coalbed methane content is greater than 8m3/t or the coal seam gas pressure is greater than 0.74MPa, which exceeds the coal seam outburst depth, coal seam gas content or coal seam gas pressure, the coalbed methane pre-drainage must be carried out in advance.
(5) In the coal infrastructure and planned mine field, according to the comprehensive exploration results and the evaluation results of coal-bearing, gas-bearing, recoverability and economy in the CBM Reserve Report, the CBM surface mining method is adopted for large-scale production, so that the gas content in the coal seam can be reduced to the maximum allowable CBM content limit for safe coal mining in the mine. However, the development time of coalbed methane should be coordinated with the coal mine infrastructure, and the principle of not affecting the normal production connection and mine ventilation safety should be followed.
(6) The maximum allowable coalbed methane content in coal mine safety mining is influenced by many factors, such as coalbed methane geological conditions, mine gas conditions, coal mining intensity, mine scale, technical conditions, ventilation safety measures, recovery rate, etc. According to "Coal Mine Safety Regulations", the maximum allowable wind speed of return air in coal mining face, tunneling face and roadway is 4m/s, and the maximum allowable methane concentration of return air is 1.5%. Therefore, according to the mathematical relationship between the maximum allowable methane concentration in return air flow and absolute emission, air volume, relative emission, residual gas content, recoverable desorption amount, extracted gas content, geometric parameters of return air roadway, maximum allowable wind speed, advancing speed of coal face and residual desorption amount per ton of coal, a general formula for calculating the maximum allowable methane content in safe coal mining is derived:
Technical progress of coalbed methane in China: 20 1 1 Proceedings of the symposium on coalbed methane.
Where: Cp is the maximum allowable gas content (m3/t); Cic is the original gas content per ton of coal (m3/t); β is the coal recovery rate (%); ε is other influencing factors; Mc is the maximum allowable concentration of methane (%); Sh is the cross-sectional area of return air lane (m2); Vh is the maximum allowable wind speed (m/s) in the return air lane; P is the coal output per unit time (t/s); N is the multiple of mining influence distance and coal mining advancing speed per unit time.
Using the above formula of the maximum allowable gas content model, the calculation and statistical results of the maximum allowable gas content of safe coal mining in national 10 key mining areas are shown in Table 4.
Table 4 Calculation and statistical results of maximum allowable gas content for safe coal mining in national 10 key mining areas
Referring to foreign experience, different countries have different regulations on the maximum allowable coalbed methane content index for safe coal mining in mines, which is 3.0m3/t in Australia and 5.0m3/t in the United States. Because of the great differences in geological conditions, mining technology, coal types and regions in China, most of the high gas mining areas are concentrated in middle and high coal rank areas. According to the comprehensive analysis results of previous test statistics, it is suggested that the evaluation index of the maximum allowable content of coalbed methane for safe mining in coal mines in China is:
(1) 6.0m3/t is suitable for medium and high rank coal;
(2) Low rank coal is calculated as 1.5m3/t;
(3) coefficient of coal seam firmness f
5 concluding remarks
The coordinated development of coalbed methane and coal is mainly to improve the safety of coal mines, improve the comprehensive benefits of the development of coalbed methane and coal enterprises, save energy and reduce emissions, and meet the growing energy demand of the country. With the technical progress and concept innovation, coal mine production has made great achievements in system simplification, layout optimization, production intensification, mining mechanization and equipment enlargement. It promotes the improvement of coal production capacity, the increase of coal mining intensity, the shortening of mining connection time and the increase of mine ventilation difficulty, so it puts forward higher requirements for coal mine gas control. To maintain a balanced and stable coal production and improve the coal supply guarantee capacity, we must adhere to the scientific development path and take the coordinated development of coalbed methane and coal as an important measure to improve economic benefits and safety guarantee. Therefore, it is imperative to establish a coordinated development mechanism and technical system of coalbed methane and coal to promote the coordinated development of coalbed methane and coal in related industries across the country.
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