(China Petroleum Coalbed Methane Co., Ltd., Beijing 100028)
Abstract: "Clean and low carbon" is a global trend. Accelerating the exploration and development of coalbed methane is of great strategic significance for reducing coal mine gas accidents, protecting atmospheric environment, improving energy structure and ensuring energy security. China has been increasing the development of coalbed methane, and has issued a series of encouraging policies such as price concessions, tax concessions, development subsidies, resource management, and mineral rights protection, forming three major coalbed methane enterprises, namely PetroChina, Jinmei Group and Zhonglian Coal, but the overall scale of the industry is small at present. Aiming at the problem of mineral rights, three cooperation modes are formed to promote the coordinated development of coal mining and natural gas production. Namely: Qinnan mode, Lu 'an mode and Sanjiao mode. Technically, supporting technologies for coalbed methane exploration and development under different coal ranks and geological conditions have been initially formed, a high-level coalbed methane laboratory has been built, and substantial breakthroughs have been made in the development of low-rank coal reservoirs in areas below 800 meters.
By the end of 20 10, 5,426 coalbed methane wells had been drilled in China, and the proven geological reserves of coalbed methane exceeded 290 billion cubic meters. The cumulative production capacity exceeds 30× 108m3/a, the annual output is 15× 108m3, and the commodity gas volume is11.8×108m3. The transportation, compression/liquefaction capacity of the completed pipeline is 56×108m3/a/a. By June of 201year, the daily output of coalbed methane in China exceeded 400× 104m3. A relatively complete coalbed methane pipe network has been built or is under construction. Qinnan, Hancheng, Daning-Jixian and Baode are all adjacent to the existing natural gas trunk lines.
China is rich in coalbed methane resources, with great potential and good prospects. In particular, it is suggested to strengthen research and development in four aspects, relying on technological progress: first, adjust countermeasures according to resource distribution research; Second, the implementation of national policies and mutual cooperation between enterprises need to be further strengthened; Third, strengthen the technical research on improving single well production and comprehensive benefits; The fourth is to establish a unified information platform to avoid disorderly competition and repeated investment. This will greatly promote the rapid development of coalbed methane industry.
Keywords: China; Coalbed methane; Development; Industry; Technology; Current situation; prospect
Present situation and prospect of coalbed methane exploration and development in China
Xu, Liu Lin, Zeng, Dong Yushan, and
(China Petroleum Coalbed Methane Co., Ltd., Beijing 100028, China)
Abstract: The global trend of "clean and low carbon" has been formed. Accelerating the exploration and development of coalbed methane is of great significance for reducing coal mine gas accidents, protecting atmospheric environment and improving energy structure. The development of coalbed methane has been intensified, and a series of incentive policies have been introduced, such as preferential prices, tax incentives, development subsidies, resource management and mineral rights protection. Three coal-bed methane enterprises have emerged, including PetroChina, JAMG and CUCBM, but the current industrial scale is relatively small. Considering the problem of exploration right, three cooperation modes, Qinnan mode, Lu 'an mode and Sanjiao mode, were developed to promote the coordinated development of gas drainage and coal mining. In terms of technology, several exploration and development technologies have been developed, which are suitable for various coal rank coalbed methane and different geological conditions, and a high-profile coalbed methane laboratory has been established. In addition, substantial breakthroughs have been made in coalbed methane exploration over 800 meters and development of low-rank coalbed methane.
By the end of 20 10, 5,426 coalbed methane wells have been drilled, with proven geological reserves of about 290 billion cubic meters. The annual production capacity of surface mining exceeds 3 billion cubic meters, with a production capacity of10.50 billion cubic meters/year, including commercial production of1.10.80 billion cubic meters/year, and the production capacity of pipeline transportation, CNG and LNG is 5.6 billion cubic meters/year. As of June, the national coalbed methane production has exceeded 4 million cubic meters/day. Qinnan, Hancheng, Daning-Jixian and Baode are all close to the main existing pipelines.
China is rich in coalbed methane resources, with great potential and broad prospects. To this end, the following four suggestions are put forward: (1) make a plan according to the allocation of resources; Further coordinate government policies and entrepreneurs' performance; Strive to make technological breakthroughs in improving single well production and comprehensive economic benefits; Establish a unified information platform to avoid disorderly competition and repeated investment. These four suggestions are likely to promote the development of coalbed methane industry.
Keywords: China; CBM development; Industry; Technology; Status; prospect
introduce
Coalbed methane, commonly known as gas, is mainly composed of methane, which is formed during coalification. It mainly exists in three forms: adsorption on the surface of coal pores, distribution in coal pores and cracks, and dissolution in coal water, with adsorption as the main form. When the amount of hydrocarbon generation in coal seam increases or the external temperature and pressure conditions change, the three forms of occurrence can be transformed into each other. "Clean and low-carbon" is a global trend, and energy transformation and low-carbon economy have become an important strategy for economic and social development of all countries in the world.
The development and utilization of coalbed methane has the advantage of "killing three birds with one stone". First of all, it is a clean, efficient and safe new energy source, and combustion hardly produces any waste gas, which is conducive to optimizing the energy structure and making up for the energy shortage; Moreover, gas is the "first killer" of coal mine safety, and its development is beneficial to coal mine safety production and reduces coal mine gas accidents; At the same time, it is also a gas with strong greenhouse effect, which is 20 times that of CO2. Developing coalbed methane can effectively reduce the greenhouse effect. Generally speaking, it embodies three major benefits: economy, safety and environmental protection. Accelerating the exploration and development of coalbed methane is of great strategic significance for reducing coal mine gas accidents, protecting atmospheric environment, improving energy structure and ensuring energy security. Coal bed methane mining methods are divided into underground drainage and surface drainage. Surface drainage is basically the same as conventional oil and gas production technology in drilling and completion, logging, fracturing, drainage and gathering and transportation.
1 World CBM resources and industry status
1. 1 resource allocation
The resources of coalbed methane with a buried depth of less than 2000m in the world are about 260× 1 0/2m3, which are mainly distributed in Russian, Canadian, China, American, Australian and other countries (Figure1).
Figure 1 Distribution of coalbed methane resources in the world
1.2 industry status
At present, the development of coalbed methane industry in the United States, Canada, Australia and other countries tends to be mature. Since the 1980s, 14 coal-bearing basins in the United States have been put into exploration and development of coalbed methane, with proven recoverable reserves of 3× 1, 01.2m3. In 2009, there were more than 50,000 coalbed methane production wells with an output of 542× 108m3. The proportion of coalbed methane production in the total natural gas production is increasing day by day, and the proportion of coalbed methane production reached 9% in 2009. Canada's coalbed methane industry has developed rapidly. 1987 started exploration and was developed on a large scale in 2002. In 2009, 7,700 wells were produced, and the output reached 60× 108m3. Australia has also formed an industrial scale. It is mainly distributed in the three coal-bearing basins of Sydney, surat and Bowen in the east. In 2005, the number of production wells was 1.300, and the output was1.2×1.08m3. In 2009, the output reached 48×1.08m3. ..
1.3 technical status quo
Through long-term theoretical and technical research and development, there are currently four major technologies and four major engineering technologies in the world. The four main technologies include: geological selection theory and high-yield enrichment area prediction technology, coalbed methane reservoir evaluation technology, air drilling, open hole cave completion technology and multi-branch horizontal well drilling technology.
The four major engineering technologies include: coiled tubing drilling, small-scale nitrogen reservoir reconstruction technology, short-radius drilling and U-shaped horizontal well technology, coal-bed methane production technology by injecting nitrogen and carbon dioxide, and integration technology of coal mining and gas production.
2 Status of CBM industry in China
2. 1 current situation of exploration and development
Influenced by the rapid development of coalbed methane in the United States, Canada, Australia and other countries, and a series of preferential policies issued by the state, the scale and enterprises of coalbed methane development in China have developed rapidly, forming three major coalbed methane production enterprises: China Petroleum, Shanxi Coal Group and China United Coal.
By the end of 20 10, 5,426 coalbed methane wells had been drilled in China, and the proven geological reserves of coalbed methane exceeded 290 billion cubic meters. The cumulative production capacity is over 30× 108m3/ year, the annual output of surface drainage is 15× 108m3, and the commodity gas volume is11.8×108m3. The transportation, compression/liquefaction capacity of the completed pipeline is 56×108m3/a/a. By June of 201year, the daily output of coalbed methane in China exceeded 400× 104m3.
China Petroleum: 2010/2, Ministry of Commerce and other four ministries and commissions announced that in order to further expand foreign cooperation in coalbed methane mining, three new enterprises, namely China Youshi, China Petrochemical and Henan CBM Company, were added as the first batch of pilot units. At present, the registered coalbed methane resources of China Petroleum exceed 3× 10 12m3, and the proven geological reserves account for 64% of the whole country, mainly distributed in Qinshui and eastern Hubei coalbed methane basins. In recent years, the initial evaluation, exploration selection and development pilot test of coalbed methane have been actively carried out, and the investment has been greatly increased. At present, two CBM fields above the quota of 100 billion cubic meters have been discovered in Qinshui and eastern Hubei, and the development pattern of four blocks in Qinnan, Weibei, Linfen and Lvliang has gradually taken shape. By the end of 20 10, the commodity gas volume was nearly 4× 108m3.
Through several years' exploration, we have cooperated with coal enterprises and local governments to form three cooperation modes to promote the coordinated development of coal mining and natural gas production. Namely: Qinnan model: the overlapping areas of mineral rights are divided by agreement, developed separately, and the two sides carry out downstream cooperation; Lu' an model: overall planning, step-by-step implementation, * * * maintaining mining order and avoiding repeated investment; Trinity model: gas production first, coal mining later and joint development. These models have been affirmed by Zhang Dejiang, deputy general manager and relevant state ministries.
A relatively complete coalbed methane pipe network has been built or is under construction. Qinnan, Hancheng, Daning-Jixian and Baode are all adjacent to the existing natural gas main pipeline (Figure 2).
A high-level coalbed methane laboratory has been built, and the test samples cover the vast majority of coalbed methane exploration and development zones in China, accounting for 80% of the national workload, and the technical level ranks first in the country.
The main experimental techniques include: gas content testing technology, isothermal adsorption testing technology, coal reservoir physical property analysis technology, coal seam fracturing damage testing technology and so on.
Jinmei Group: By the end of 20 10, 25 wells have been drilled, and the surface drainage output has reached 9× 108m3. Construction of Sihe-Jincheng 10× 108m3/a gas pipeline; Participate in the construction of Jincheng-Aibo gas pipeline. The daily liquefaction capacity of the coal-bed methane liquefaction project jointly invested with Hongkong Hua Gang * * can reach 25×104m3; ; Put into operation 120 MW coalbed methane power plant. The development zone involves Qinshui, Yangquan, Shouyang, Xishan, Ningxian and Jiaozuo, Henan.
Merger of Zhonglian Coal and CNOOC: At present, Zhonglian Coal has a mining right area of 2× 104km2, of which the foreign cooperation block area is 1.6× 104km2. By the end of 20 10, the national Qinnan high-tech industrialization demonstration project and Duanshi national oil and gas strategic selection demonstration project will be completed in Panhe, Qinshui Basin.
At present, 672 wells have been drilled and 230 wells have been put into production, with a daily gas production of 50× 104m3. 20 10 CNOOC successfully intervened in the exploration and development of coalbed methane by acquiring 50% shares of Zhonglian Coal, which laid the foundation for the development of coalbed methane industry.
Fig. 2 Schematic diagram of main oil and gas pipelines in China.
Fuxin Coal Industry: Fuxin Mining Group cooperated with Liaohe Petroleum Exploration Bureau to develop three cooperative mining modes of coalbed methane, which significantly improved the overall development efficiency. Three development modes include: short-radius hydraulic jet drilling in underdeveloped areas has achieved practical results; In the dynamic mining area, the surface negative pressure drainage technology is applied to realize gas linkage mining; Drilling through the goaf is successful. In 20 10, 52 wells have been drilled, with daily gas production of 10× 104m3 and commercial gas of 3226× 104m3. Three CNG filling stations have been built, which are mainly used in Panjin and Fuxin.
Sinopec: The coalbed methane mineral rights are mainly Heshun block in the north of Qinshui Basin and Yanchuan block in the southeast of Hubei Province. 34 wells were drilled in 20 10, and the gas production was 84× 104m3. At present, the daily gas production is nearly 3000m3. 20 10 East China Bureau and Huainan Mining signed the Letter of Intent for CBM R&D Cooperation, and selected 100km2 favorable block in Huainan Panxie Mining Area to jointly develop CBM resources. 20 1 1 signed a framework agreement with Australia Pacific in Beijing, and both parties established non-binding key commercial terms.
Others: Joint ventures such as Longmen, Greco, Far East Energy, Asian-American continent and other private enterprises have set foot in the exploration and development of coalbed methane one after another, and increased the scale of capacity construction, among which the Asian-American continent currently produces gas per day 19.7× 104 m3.
Generally speaking, the southern Qinshui Basin has become a hot spot of coalbed methane development in China, with a production capacity of nearly 25× 108m3/a and a daily gas production of nearly 380× 104m3, realizing the scale of pipeline transportation and commercial operation, and initially forming an industrial pattern integrating production, transportation and marketing.
2.2 Government preferential policies and technical support
In order to encourage the development of coalbed methane industry, China government has issued a series of preferential policies, including price concessions, tax concessions, development subsidies, resource management and mineral rights protection. (table 1), the effect is remarkable.
Table 1 Preferential Policies of China Government to Encourage the Development of Coalbed Methane Industry
At the same time, it also gave strong support at the technical level. Since 2007, the National Development and Reform Commission has set up two national engineering research centers, namely, the development and utilization of coalbed methane and coal mine gas control, and the Ministry of Science and Technology has set up a major national science and technology project of "large oil and gas fields and coalbed methane development". China Petroleum has established a professional coalbed methane company, and set up a major scientific and technological project of "Key Technology and Demonstration Project of CBM Exploration and Development". All these have created conditions for the development and technological progress of coalbed methane industry.
2.3 technical status quo
The geological conditions in China are different from those in the United States. At present, the development of coalbed methane originates from the earliest theory in the United States. With the expansion of development scale, the reservoir characteristics of coalbed methane under different types of coal rank, coal structure, structural conditions and hydrogeological conditions were tested on site. Practice has proved that whether this theory is fully applicable to the geological conditions of coalbed methane in China needs further confirmation. According to the geological conditions of different basins in China, different exploration and development technologies have been developed, and some have made breakthroughs.
2.3. 1 There is a new understanding in geology.
There is a new breakthrough in the evaluation method of favorable areas: through the comprehensive geological study of coal and rock characteristics, gas content, permeability and gas production, the evaluation standard of high-concentration producing areas is established, and the division standard and method of development units in capacity building areas are put forward.
There is a breakthrough in the production of 800-meter-deep coalbed methane wells: it is generally believed that with the increase of coal seam buried depth, the pressure increases, the permeability drops sharply and the gas production decreases. At present, the depth of domestic commercial development is in the shallow area of 800m, with the deepening of exploration and development, industrial airflow has been obtained from deep wells with a depth of 800 m (the maximum gas production is 2885m3/d) (Figure 3), but the law of coal seam gas production is still unclear, which is being confirmed by strengthening research and drainage tests of large well groups.
Figure 3 Drainage-production curve of 800-meter deep well
The permeability of coal reservoirs is generally low, and reservoir protection is the key; the study of coal reservoir conditions is the key restrictive factor for coalbed methane development. The permeability of No.3 coal in Qinshui Basin is (0.013 ~ 0.43 )×10-3 μ m2, with an average value of 0.12×10-3 μ m2; Eastern Hubei (0.22 ~ 12) × 10-3μ m2, with an average of 1× 10-3μm2. Generally speaking, coal seam has poor physical properties and strong heterogeneity, so strengthening reservoir protection during drilling is the key. In the process of drilling and fracturing, try to use underbalanced drilling and low-damage fracturing fluid with little damage to coal reservoirs around the wellbore.
2.3.2 There are new measures for site management.
The well spacing of high coal rank development well pattern is explored. Because the physical properties of high rank coalbed methane reservoirs in China are quite different from those in foreign countries, it has been proved that the well spacing of 300m×300m, which has been used all the time, is not completely appropriate, mainly due to the small number of high-yield wells, low production and unreasonable production structure. Therefore, through fine geological research, with the goal of increasing single well production, numerical simulation and pilot test are carried out on gas production effects with different well spacing, and the 200m×200m well pattern and well spacing for high rank coalbed methane development are explored. At the same time, the implementation of drainage aid in horizontal underground has also achieved initial results.
2.3.3 New progress has been made in supporting engineering technology.
3-D seismic exploration: A 3-D earthquake of 100km2 was carried out in Hancheng area, and the data quality was obviously better than that of 2-D, and the description of small faults was clearer (Figure 4), which effectively guided the well pattern deployment.
Fig. 4 Comparison of 3D and 2D profiles in Hancheng area
Feather horizontal well drilling: Through market-oriented operation, it broke the monopoly position of foreign companies in the field of feather horizontal well construction, got rid of the situation that feather horizontal well drilling was completely dependent on foreign companies, and the cost was greatly reduced.
Matching fracturing technology: On the basis of experimental analysis of coal seam, combined with a large number of fracturing practices, new technologies such as "variable displacement, low damage", "high pressure well treatment technology, layered fracturing technology" have been formed, using low-density proppant, plugging and decompression, and one trip of two-layer partial pressure.
Drainage gas recovery technology: forming the principle of slow, stable, long-term and continuous; Three key links for cultivating high-yield wells are formed: liquid level control, casing pressure control and pulverized coal control; In view of the low cost strategy, two kinds of wellhead drainage and gas production equipment combinations are formed: motor+pumping unit and pneumatic motor+pumping unit.
Ground gathering and transportation processing: standardized design, modular construction and automatic management, basically achieving low-cost and efficient operation.
2.4 Utilization status quo
In 2009, six coal-bed methane liquefaction plants were built nationwide, with liquefaction capacity of 260× 104m3/d, 20 10/0, 300× 104m3/d and 700× 104m3/d in 2020. In addition, it is mainly used for low-concentration gas power generation, residents' life, synthetic ammonia, formaldehyde, methanol, carbon black and other chemical raw materials, and gradually established an industrial system for the development and utilization of coalbed methane and coal mine gas.
2.5 Existing problems
Technology: Technology is the main problem that restricts the slow progress of the industry at present. At present, the main problems faced include: gas control factors in high permeability and enrichment areas of coalbed methane, development theory that conforms to China's coalbed methane geological conditions and is used to guide production practice, and key technologies and corresponding equipment suitable for China's geological conditions such as completion, fracturing and drainage.
Management: It mainly includes: the overlapping of coalbed methane and coal mining rights, the difficulty in implementing policies such as gas production first, coal mining later and power generation on the Internet, high dependence on foreign cooperation, limited self-operated projects, small pipeline scale, scattered market and great uncertainty.
3 CBM development prospects and suggestions
With the development of national economy, the rapid growth of natural gas demand provides opportunities for the development of coalbed methane. Since 2000, the average annual growth rate of natural gas has reached 16% (Figure 5). At the end of 2009, the total consumption of natural gas in China was 875× 108m3, the demand for natural gas in 20 10 exceeded 1400× 108m3, and the supply capacity was about 65,438. In 20 15, the estimated natural gas demand is 2600× 108m3, and the supply capacity is only 1600× 108m3. By 2020, the natural gas gap will exceed 1000× 108m3, which is unconventional natural gas such as coalbed methane.
3. 1 Development prospect
According to the relevant planning, by 20 15, the national CBM production will reach100×108m3; In 2020, the natural gas output will be about 2020× 108m3, of which the unconventional natural gas output will reach 620× 108m3, and the ground developed coalbed methane will reach 200× 108m3.
Figure 5 Trend of natural gas consumption in China from 2000 to 2008.
At the same time, relevant enterprises have also formulated the development goals of the Twelfth Five-Year Plan (Table 2).
Table 2 Prediction Table of CBM Ground Development in National Key Areas and Enterprises
Whether the above-mentioned objectives can be successfully realized, what is the prospect, and whether the exploration and development and industrial scale can develop rapidly mainly depend on the further implementation of national policies and the investment of several major enterprises. What is particularly important is that these enterprises must pay great attention to the technological progress and breakthrough of coalbed methane occurrence conditions, rather than the problem of funds. China Petroleum will further increase investment to promote the rapid development of coalbed methane industry. It is necessary to intensify the exploration and development of two key industrial bases in the south of Qinshui Basin and the east of Ordos Basin, and actively explore supporting technologies for coalbed methane development in peripheral basins. It is estimated that the proven geological reserves of coalbed methane will increase by 2000× 108m3 in 20 12, which will provide resource guarantee for the construction capacity. The annual production capacity of 20 13 is 45× 108m3/ year. The output of 20 15 reached 45× 108m3, and the commodity volume was 40× 108m3, making it the first CBM production enterprise in China. At the same time, it has become a leader in business technology, a standard setter and a leader in industry development. By 2020, the commercial volume of coalbed methane is expected to reach 100× 108m3, which will become an important part of China's main oil industry and a strategic economic growth point.
3.2 Countermeasures and Suggestions
3.2. 1 Adjust the countermeasures according to the resource distribution research.
The total resources of coalbed methane with buried depth less than 2000m in China are 36.8× 10 12m3, and the recoverable resources are about10.8×10/2m3. There are 8 river basins with resources greater than1×10/2m3, and the total resources are 28× 10 12m3, accounting for 76% of the whole country, mainly distributed in the central and western regions. The resources with the buried depth less than 1000m are14×10/2m3, which is the main resources developed at present. Low rank coalbed methane resources account for 43%, but at present, medium and high rank coalbed methane resources are mainly developed. Therefore, it is necessary to strengthen the R&D experiments on the development of coalbed methane in the middle and deep layers (buried more than 800 meters) and low-rank coal in the western region, and strive for a substantial breakthrough in a wider scope.
3.2.2 The implementation of national policies and mutual cooperation among enterprises should be further strengthened.
Improve relevant policies and measures, formulate a unified plan for coalbed methane and coal development, realize seamless connection, effectively implement "gas production first, then coal mining" and make full use of resources. The three cooperation modes of coal mining and gas production need to be further expanded; Actively promote the development of coalbed methane industry and the integrated cooperation of coal mine gas prevention and control.
3.2.3 Strengthen technical research on improving single well production and comprehensive benefits.
In view of the key technology of coalbed methane exploration and development, it is necessary to strengthen research. According to the geological characteristics of coalbed methane, the corresponding supporting facilities and equipment for drilling, fracturing, drainage and pipeline transportation will be further developed, and the research and development of key technologies for the development of pinnate horizontal wells will be intensified.
3.2.4 Establish a unified information platform to avoid disorderly competition and repeated investment.
Strengthen information channels, realize resource sharing, and avoid disorderly competition and repeated investment. It is a very important basic work to establish a unified information management system for coalbed methane industry. It includes two aspects: strengthening the digital construction of coalbed methane fields within enterprises, and strengthening the statistics, exchange and release of industry technology and industry information at the national level to provide a unified information construction standard for coalbed methane industry.
Concluding remarks
Low-carbon economy is the only way to develop China's energy economy. In order to reduce carbon emissions from the source and lead the diversification of energy structure and industry, the gap between supply and demand of natural gas will exist for a long time, and the demand for coalbed methane will continue to increase. China is rich in coalbed methane resources. At present, the overall scale of the industry is small, but it has great potential and good prospects. Strengthening research and development and relying on technological progress will greatly promote the rapid development of coalbed methane industry.
refer to
Xu et al. Development direction of CBM exploration and development theory and technology [J]. China Petroleum Exploration, 2008, (5)
[2] Song Yan et al. The mechanism of coalbed methane accumulation and the theoretical basis of economic development [M]. Beijing: Science Press, 2005
[3] Li Jingming et al. Characteristics of coalbed methane resources in China and development countermeasures [J]. Natural gas industry, 2009, (4)
[4] Guo Present situation and enlightenment of coalbed methane exploration and development in Hancheng block, Proceedings of 2006 symposium on coalbed methane [C]. Beijing: Geological Publishing House.
Zhao Qingbo and others. Evaluation theory and exploration technology of coalbed methane geological selection [M]. Beijing Petroleum Industry Press 2009
Chen et al. Influence of pulverized coal production on the productivity of high-rank coalbed methane wells and its control [J]. Acta Sinica Sinica, 2009, (34)2
[7] Sun Maoyuan. Some problems in the development and utilization of coalbed methane resources [J]. China Coal, 2005, (3)
Liu Honglin, Li Jingming, Ningning, Li Guizhong. Present situation, prospect and suggestions on the industrialization of coalbed methane exploration and development in China [J]. Natural Gas Technology, 2007, (04)
Xian Baoan, Cui, Lan Haifeng, Li. Key technologies and comprehensive utilization of coalbed methane development in China [J]. Natural gas industry, 2004, (05)
[10] Ye Jianping. Summary of the progress of coalbed methane exploration and development in China [J]. Geological Bulletin, 2006, (Z2)
Cui. Development and utilization of coalbed methane at home and abroad [J]. Land and Resources Information, 2005, (1 1)
Into a TV. Progress and trend of coalbed methane exploration and development in China [J]. China Coalfield Geology, 2007, (1)
[13] Peng Xianqiang, Zhang Baosheng, Chu, Comprehensive benefit evaluation of coalbed methane development in China [J]. Natural gas industry, 2008, (3)
[14] Li Wuzhong, Tian,,. Reservoir forming characteristics and exploration and development technology of low rank coalbed methane [J]. Natural gas industry, 2008, (3)
Yan and Hao. Development and utilization of coalbed methane abroad and its technical level [J]. Petroleum Science and Technology Forum, 2007, (6)
Zhai Guangming, He. Seize the opportunity to accelerate the development of China's coalbed methane industry [J]. Natural gas industry, 2008, (3)
[17]NPC's working paper on global oil and gas research. Special Paper #29 Unconventional Natural Gas. July 2007 18.
[18] Si Guangyao, Cai Wu, Zhang Qiang. Present situation and prospect of CBM utilization at home and abroad [J]. China CBM, 2009, (6)
Facing the grim facts about energy. Washington, DC: National Petroleum Commission, 2007.
Hou Yupin, Zhang. Discussion on mining coalbed methane with ultra-short radius horizontal wells [J]. Mining Machinery, 2005, (6)
[2 1] Yan, Hao. Development and utilization of coalbed methane abroad and its technical level [J]. Petroleum Science and Technology Forum, 2006, (6)
[22] Liu Yijun. Applying new technology to promote coalbed methane development [J]. Geological Bulletin, 2007, (26)