The United States is a country rich in coalbed methane resources and the first country to successfully explore and develop coalbed methane. At the beginning of the 20th century, coal mine gas drainage technology spread to the United States. 19 15, the horizontal well test of mine roadway was carried out. In 1930s, gas drainage began in the upper sandstone of coal mine goaf. 1952 successfully used shallow coal seam 140m vertical well to drain gas, and the single well output was 1 100 m3/d, so the United States really developed and utilized coalbed methane as a mineral resource. That was after the 1960s, when America's natural gas reserves declined and there was a shortage of energy. In order to make up for the shortage of natural gas reserves, coalbed methane is included in the evaluation of energy and mineral resources. 197 1 A five-point well pattern test was conducted in the Warrior Basin, and the single well production after fracturing was 2800 m3/d. During the period of 1978- 1982, the single-well production technology of coalbed methane was studied. The single-well production of shallow coal seams in Warril basin increased from 2000m3/d to 3000m3/d, and that in San Juan basin reached 42× 104m3/d, with a cumulative production of 5× 108. 1977 to 1982, the exploration and development of coalbed methane in the United States is included in the natural gas exploitation plan. 13 coal-bearing coalbed methane basin has an area of 158× 104km2 and a buried depth of 1829m(6000ft). These sedimentary basins are mainly distributed in the relatively stable areas between the eastern Appalachian fold belt, the western Cordillera fold belt and the central landmass. In the eastern region, there are Carboniferous and Permian coalbed methane basins, such as North Appalachia, Central Appalachia, Illinois, Warrior and Akoma. There are Cretaceous and Tertiary coalbed methane basins in the western region, such as Raton, San Juan, Pischens, Utah, Great Green River, Wende River, Pide River and Washington. Among them, San Juan and Varyl basins are rich in resources, with good resource prospects and high degree of exploration and development. During the decade from the end of 1980s to 1990s, large-scale exploration and development of coalbed methane were carried out in San Juan and Varyl basins, and considerable production capacity was formed. At present, it has expanded from San Juan and Varille basins to six basins, such as Yinta, Fenhe, Raton and Appalachia, and successfully explored the upper Cretaceous coal measures in Yinta and Fenhe basins. According to incomplete statistics, only 644 CBM wells were drilled in the United States in 1988, more than 2,000 wells were drilled in 1990, and 1999 wells were drilled in 10600. During the ten years from 1980 to 1990, the annual production of coalbed methane in the United States jumped from less than 1× 108m3 to 52× 108m3, and from 1990 to198m3.
1988 American Natural Gas Institute estimated that 13 coal-bearing coalbed methane basin resources were1.32×10/2m3, and estimated that 14 coal-bearing coalbed methane basin resources were (shallow resources). 1990, the estimated coalbed methane resources are11.32×10/2m3, and the recoverable geological reserves are 2.55×10/2m3. The estimated recoverable reserves of 1992 are (1.75 ~ 3.82) ×1012m3, accounting for 5% of natural gas reserves. According to the calculation of 1994, the resources of 18 coal-bearing coalbed methane basin or block are19×10/2m3, the recoverable reserves are 3×1kloc-0/2m3, and the remaining proved recoverable. According to the estimation of American Energy Information Center, 1997 coalbed methane reserves are 3,247×108m3, which is 8% higher than the previous year, twice as much as 1990, accounting for 7% of the total natural gas reserves.
Canada and the United States are located in the North American continent, and a vast and stable sedimentary area has developed between the land mass in central Canada and the Cordillera fold belt in the west. Sedimentary rock series developed since Paleozoic, and coal-bearing rock series developed in late Paleozoic and Mesozoic. Since 1980s, coalbed methane exploration has been carried out in Albert Basin in the west. It is estimated that the coalbed methane resources are19×10/2m3, and the recoverable resources are 7×10/2m3. In the early 1980s, coalbed methane resources were extensively explored and evaluated, and the tests of four coalbed methane wells built in Albert Basin showed good results.
The exploration of coalbed methane in Oceania is mainly in Australia and New Zealand. The CBM resources in Australia are (8.5 ~14.6) ×1012m3. Mainly concentrated in Permian-Triassic coal-bearing basins in the east, such as Sydney, Kennedy, Born and Galilee. In order to find natural gas resources closer to the economically developed cities in the southeast coast, Australia has carried out coalbed methane exploration, thus becoming a country with an early commercial breakthrough in coalbed methane exploration and development. From the late 1970s to the early 1990s, hydraulic fracturing technology was used to drill coalbed methane in Australia, but it failed. Until the early 1990s, there was no major breakthrough in CBM exploration and testing. The reason for the long-term unsuccessful exploration of coalbed methane in Australia is that the imported modern exploration and development technology of coalbed methane in the United States has not been better combined with the complex geological and structural conditions in Australia. In recent years, Australia has stepped up its exploration efforts, and has drilled more than one coalbed methane well 100, making a new breakthrough in exploration and development, shifting from exploration to development and production, and some production wells have been commercialized.
Coalbed methane exploration in Australia is mainly concentrated in the Garigli Basin, which is relatively stable between the Tasman fold belt on the east coast and the Australian landmass in the west, the Bowen Basin, the Gunida Basin and the Sydney Basin, and the Permian-Triassic coalbed methane basins such as Clarence Morton, Ipswich and Laura. The widely developed Permian coal measures strata are the target coal seams for coalbed methane exploration.
1994 There are 6 CBM exploration wells in Sydney Basin, and the estimated CBM resource is 3.68× 3× 104km2, that is, 3.68×10/2m3. Two appraisal wells were drilled in Gunida Basin from 1993 to 1995, and the tested permeability reached 45× 10-3μm2. Galilee basin covers an area of 23.4× 104km2, and there are 8 drilled wells and test wells. The tested permeability reaches (13 ~ 52 )× 10-3μ m2, and the geological reserves of coalbed methane are estimated to be 400× 108m3. In recent years, it has been successful in Born Basin. From 1994 to 1995, 17 wells were tested, of which the output of 2 wells was more than 2.8× 104m3/d, and the output of 2 wells in the eastern margin of the basin was 7./kloc-0 /×/kloc-0 respectively. By 1996, the single well production in the south-central part of the basin reached 4000m3/d, the commercial production reached 10.58× 104m3/d, and five horizontal wells were put into operation at the same time, with the well depth of1000m3 ~1300m.
Europe is the ancestor of using coal field gas, but it has fallen behind in modern times. It was not until the 1990s that modern surface vertical drilling and mining technology was adopted. Britain and Central European countries are located in the Beihai-Central European Basin, and the coal measures strata formed since Carboniferous are very developed, which has a good prospect of coalbed methane resources. Britain, Spain, France, Belgium, Czech Republic, Poland and Hungary have successively carried out coalbed methane exploration. Since 1992, exploration experiments have been carried out in different areas and resources have been evaluated. At the beginning of 1992, Britain completed the first coalbed methane well with a depth of 1074.4 m, drilled a coal seam with a thickness of 22 m and fractured it. Recently, three coalbed methane wells were completed in the central coal area, and the daily output of each well exceeded 1000 m3. Belgium established a coalbed methane test area in Kaiping basin in the northeast, and 1992 drilled a coalbed methane well and tested it. The Czech Republic has carried out CBM exploration and development tests in Carboniferous coal measures strata in ostrava-Calfee Na basin, and estimated the resources of three blocks as (150 ~ 200) × 108m3. After successful exploration test, the production capacity of 1998 is 2×108m3/a. ..
Russia, Ukraine and other CIS countries span Eurasia, ranking first in the world in coalbed methane resources and coal resources. However, the exploration and development of coalbed methane started late and is still in the stage of resource evaluation. 1998 drilled three coalbed methane wells with 400~500 m in Lviv-Warren coalfield in southwest Ukraine.
India has also carried out coalbed methane exploration in recent years. Most of the Indian plate is an ancient block (shield), and the sedimentary basins are mainly distributed in the northern and coastal peripheral areas. At present, coalbed methane exploration is mainly located in Kambei Basin, which is a rift basin with stable land mass in the west, and Cretaceous and Tertiary coal measures are the main target coal seams. The coalbed methane resources in India are 0.8× 10 12m3, which also has considerable resource potential.
The coalbed methane resources in Indonesia have a certain potential, and the coal reserves are 320× 108t. Sedimentary rock series has developed well since Carboniferous, and Paleogene coal-bearing rock series is a good target coal seam for coalbed methane exploration. CBM exploration in Indonesia has just begun.
In South America, Chile and Argentina have also carried out coalbed methane exploration. Tertiary lacustrine deposits are developed in Magellan basin, and there are target coal seams for coalbed methane exploration.
South Africa and Zimbabwe are exploring coalbed methane in southern Africa. The coalbed methane resources in South Africa are 0.72× 10 12m3, and the resource potential is considerable. The coal-bearing sedimentary basin in Zimbabwe is not very large, and good coal-bearing strata are developed in Carboniferous Kalu Formation and Permian Wanji Coal Measures. Since 1994, coalbed methane wells have been built to explore and evaluate some blocks in sedimentary basins.
China is a country rich in coal resources and coalbed methane resources. The coal-forming period in China is similar to that in other parts of the world, mainly including Late Carboniferous, Permian, Late Triassic, Early Middle Jurassic, Late Jurassic-Early Cretaceous and Tertiary. The basic structural units of Chinese mainland are the stable area represented by landmass and the active area represented by continental margin. According to the division of plate tectonics, Chinese mainland and the sea area span six plate tectonics, including four plates except Tibet-Yunnan plate, and coal-bearing coalbed methane basins are mainly distributed in Tarim-North China plate, South China plate and Junggar-Xing 'an active belt of Siberia plate in China. According to the statistical data of coalbed methane basin research, the total coalbed methane resources in China coal-bearing basin are 20 1205× 108m3, of which the buried depth of coal seam is 8m3, the buried depth of coal seam is 1500 ~ 2000m, and the resources are 35915.3x1. Mainly distributed in three plate tectonic units: Tarim-North China plate, mainly distributed in North China landmass. Coal seam buried depth of 8m3, coal seam buried depth 1500 ~ 2000m. The resource amount is 27522.5× 108m3, and the total resource amount is 15365. 1× 65438. South China plate is mainly distributed in Yangtze block, with a coal seam depth of 8m3 and a coal seam depth of 1500 ~ 2000m. The resources are 6325.7× 108m3, and the total resources are 41191.4×108m3. The buried depth of coal seam in Junggar-Xing 'an active belt of Siberian plate (including Tianshan-Chifeng active belt) is 8m3, the buried depth of coal seam is 1500 ~ 2000m, the resources are 2020.8× 108m3, and the total resources are 6308.2× 108m3.
According to the statistics of coalbed methane resources in different horizons of coal-bearing basins: Carboniferous and Permian, the coal seam depth is 8m3, the coal seam depth is 1500 ~ 2000m, the resource amount is 341.2×108m3, and the total resource amount is15653. The buried depth of upper Triassic coal seam is 8m3, and the buried depth of coal seam is 1500 ~ 2000m. The resource amount is 0× 108m3, and the total resource amount is 7 1.6× 108m3. The buried depth of Jurassic coal seam is 8m3, and the buried depth of coal seam is 1500 ~ 2000m. The resources are 739.5× 108m3, and the total resources are 4 1025.8× 108. The buried depth of lower Cretaceous coal seam is 8m3, and the buried depth of coal seam is 1500 ~ 2000m. The resource amount is 1033.3× 108m3, and the total resource amount is 3493.6×108m3; . Tertiary coal seam buried depth of 8m3, coal seam buried depth1500 ~ 2000 m.. The resource amount is 3 1.4× 108m3, and the total resource amount is 74.2× 108m3.
According to the statistics of different coal rank (coal rank) of coal-bearing rock series, coalbed methane resources are anthracite and lean coal rank, with a coal seam buried depth of 8m3 and a coal seam buried depth of 1500 ~ 2000m. The resource amount is 71./kloc-0 /×108m3, and the total resource amount is 1877.8× 6508 m3. The rank of lean coal, coking coal and fat coal, the buried depth of coal seam is 8m3, the buried depth of coal seam is 1500 ~ 2000 m, the resource amount is 35825.2× 108m3, and the total resource amount is160986./kloc-0 /×/kloc-0. Gas coal, long-flame coal rank, coal seam buried depth 8m3, coal seam buried depth 1500 ~ 2000 m, resources 19× 108m3, and total resources are 38341.1×/kloc-0.
Since 1980s, China began to study the modern exploration and development technology of coalbed methane in the United States, systematically sorted out the exploration and development data of coalbed methane, conducted exploration tests in some coalfields and mines, and directly introduced exploration and development technology in cooperation with foreign companies, thus gaining a lot of valuable information and experience. In order to meet the needs of economic development and the long-term interests of environmental protection, the government attaches great importance to the development of coalbed methane industry and has accelerated the exploration and development process since the 1990s. The Ministry of Coal has set up a leading group for coalbed methane (1993), which lists the exploration, development and utilization of coalbed methane as one of the three development strategies and the second largest coal resource. The Ministry of Coal, the Ministry of Geology and Mineral Resources and the Oil and Gas Corporation jointly established Zhonglian Coalbed Methane Company (1996). Convene domestic and international seminars on CBM development strategy and specialty. The State Planning Commission, together with the Ministry of Geology and Mineral Resources, listed "Evaluation Selection Area and Engineering Technology Research of CBM Exploration and Development" as one of the national key scientific and technological projects during the Eighth Five-Year Plan period. The Ministry of Foreign Trade and Economic Cooperation, the Ministry of Coal and the Ministry of Geology and Minerals have respectively implemented the CBM exploration and development projects such as "China CBM Resources Development" (UNDP/ CPR /92/G93) and "Deep CBM Exploration" (UNDP/ CPR/91214) funded by the United Nations Development Programme. Coal, geology, petroleum and other departments and local provinces and cities have successively carried out coalbed methane exploration in different regions, and also cooperated with foreign companies such as the United States and Australia to carry out coalbed methane exploration in Hedong and Huainan. By the end of 20001,more than 200 coalbed methane exploration wells have been built in different areas, and some coal-bearing coalbed methane basins or blocks have been pre-explored and evaluated, and breakthroughs in exploration tests have been achieved in Hedong, Qinshui and Tiefa. CBM exploration and test wells are mainly distributed in North China block and Yangtze block. There are about 180 exploratory wells and test wells in the North China landmass, including more than 50 in the eastern margin of Ordos Basin, nearly 50 in the southeastern margin of Qinshui Basin and nearly 80 in the northern and southern margins of North China Basin. Three coalbed methane exploration wells in Yangzi District/KLOC-0 are distributed in Lianshao in central Hunan, Beipingle Basin in Jiangxi and Liupanshui. From the exploration horizon of coalbed methane wells, only five coalbed methane wells are distributed in Tuha basin in Junggar micro-area and Hegang basin in Nensong-Jiamusi micro-area. The target strata of most wells deployed in North China block are Carboniferous Taiyuan Formation and Permian Shanxi Formation, while the target strata of Yangtze block are Permian Longtan Formation. In Ordos Basin, only the target strata in Tuha Basin and Chang Bin area are the Middle and Lower Jurassic, while the target strata in Tiefa and Hegang Basin are the Lower Cretaceous.
In the area east of the Yellow River in the Shanxi Flexural Belt in the eastern margin of Ordos Basin (referred to as Hedong area for short), the "Deep CBM Exploration" project funded by North China Petroleum Bureau evaluated the CBM accumulation conditions of Carboniferous Taiyuan Formation and Permian Shanxi Formation. The well pattern constructed in Liulin experimental area was successfully drained in August 1994, and all seven wells were emptied, with an average single well output of 3,000m3/d, and the highest output of Well Liu 5 reached 7050m3. In recent years, the highest single well production of five well patterns in Qiaokou experimental area of the north wing of Lishi nose uplift in foreign cooperative exploration and development blocks has reached 5500m3/d. The well pattern test of 9 wells in Sanjiao Linjiaping experimental area in the north wing of Lishi nose uplift shows that the maximum output of a single well is 7000m3/d. A well pattern of 10 was formed in Zaoyuan, Guxian County, south slope of Qinshui Basin, and a drainage test was conducted. On the southern slope of Qinshui Basin, Zhonglian CBM Company obtained 402× 108m3 of proven CBM reserves in the control area of panzhuang Block 164 km2, and obtained 16303 m3/d gas production in Well TL-7. China Petroleum Group has obtained 353.26× 108m3 proven coalbed methane reserves in six well patterns in Fanzhuang block, with a controlled area of182.22km2. At the same time, the exploration test of Permian coal-bearing coalbed methane was carried out in the south of Panguan syncline (Liupanshui) in Qianxi basin of Yangtze landmass, and the exploration of Jurassic coal-bearing system and Lower Cretaceous coal-bearing system was also carried out in Fuxin basin and Tiefa basin. ..
While strengthening the process of coalbed methane exploration and development, the research on coalbed methane exploration technology and geological evaluation are carried out simultaneously. Since 1980s, North China Petroleum Bureau, an emerging oil company, has systematically studied the exploration and development technology of coalbed methane abroad, and published the translated collection of coalbed methane for the first time. Since 1990s, the occurrence conditions of Carboniferous and Permian coalbed methane in North China Basin have been evaluated and studied, and the study on geological characteristics and evaluation selection of coalbed methane in North China and its adjacent areas has been written. At the same time, North China, Southwest China, Central South China, East China and Northeast Petroleum Bureau, an emerging oil company, respectively studied the occurrence conditions and evaluation selection areas of coalbed methane in Ordos Basin, Sichuan Basin, Central South Hunan Basin Group, Lower Yangtze Region and Songliao Basin, and wrote special reports. In the early 1990s, North China Petroleum Bureau started the project of "Exploration and Development Experiment of Coalbed Methane in North China", at the same time, it started the national key scientific and technological research project of "Evaluation Selection and Engineering Technology Research of Coalbed Methane Exploration and Development" and the project of "Deep Coalbed Methane Exploration" funded by the United Nations Development Programme. Through the implementation of the trinity project, a number of domestic leading research results and the success of funded projects have been achieved. At the same time, domestic counterparts are speeding up the exploration process of coalbed methane and strengthening the research on geological theory and exploration technology of coalbed methane. The CBM exploration department of China Petroleum Group timely summarized the exploration, and after the exploration, summarized and evaluated Dacheng, Qinshui and Hedong blocks. Combined with the data at home and abroad, the author has written CBM Geology and Exploration Technology, Development Status of CBM Industry in the World, CBM Geology in China and New Progress of CBM Geological Evaluation and Exploration Technology in China. 199 1 year, Xi' an Coal Research Branch published Coal Seam Methane in China (Zhang Xinmin, Zhang Sui), and China Coal Geology Bureau compiled Coal Seam Methane Resources in China and Coal Seam Methane Resources Map in China (1:2 million). In cooperation with domestic research departments, Zhonglian CBM Company evaluated the CBM exploration prospects in Qinshui Basin, Sanjiang Basin, Liaozhong Region and Liupanshui Region, and conducted selective evaluation research for the whole country. At the same time, the handbook of coalbed methane development and utilization (Sun Maoyuan, etc. ). In addition, there are examples of CBM exploration and development abroad (Wang Xinmin, etc. ), coalbed methane reservoir evaluation and production technology (Telly et al. ) and coalbed methane geology and exploration in western Guizhou and eastern Yunnan (Guangxi).
The breakthrough of coalbed methane exploration test in China is of great strategic significance, which shows that similar events have occurred in the geological history of the North American continental plate and the Eurasian China plate, thus proving that the regularity of the formation and evolution of coal-bearing coalbed methane basins and coalbed methane reservoirs is of global significance. The breakthrough of coalbed methane exploration test in China and the exploration test results in Liulin experimental area in the eastern margin of Ordos Basin not only prove the exploration prospect of coalbed methane in Carboniferous and Permian coal-bearing measures in Ordos Basin, but also indicate that Carboniferous and Permian coal-bearing measures widely distributed in northern China since Paleozoic have the exploration prospect of coalbed methane. Tiefa fault basin in the southeastern margin of Songliao Basin is a Mesozoic fault basin developed on ancient bedrock, and there are relatively developed coal-bearing strata in the Lower Cretaceous, which also indicates that Songliao Basin also has a good prospect for coalbed methane exploration.
At the15th World Petroleum Congress, people were generally worried that there would be an energy crisis in the next century due to oil shortage. The congress affirmed that fossil fuels such as oil and natural gas were still the main energy sources for human survival before the 1950s. However, human beings are also soberly aware that non-renewable fossil fuels such as oil, natural gas and coal are limited after all. Marchctti's (1979) energy system change and theoretical substitution pattern diagram shows the evolution trend of energy structure from 1850 to 2050. Since human beings replaced wood energy with fossil fuels, in the century and a half before 2000, both coal (1920) and oil (1980) rose to the peak of energy composition ratio, and turned into a trough. Natural gas will reach its peak in 2020, while solar energy and nuclear energy are gradually on the rise.
In the energy composition of the next century, the proportion of coal will gradually decrease, but the absolute value of its exploitation will not necessarily decrease. Therefore, whether the coal mining industry continues to use new technology to increase gas drainage in mine roadway, or adopts ground vertical drilling technology to extract undeveloped coal seam in advance or extract roadway in the later stage, it is an essential measure to reduce gas disaster in mine field. While strengthening scientific and technological progress to ensure the safe production of mining industry, it will inevitably promote the development of coalbed methane industry.
China is one of the countries with high gas emissions, accounting for 1/3 of the world total. In order to discharge coal mine roadway gas into the atmosphere, it not only caused serious air pollution, but also consumed a lot of power resources. Protecting the global ozone layer has become a major event that human beings care about their own living environment. The greenhouse effect caused by methane (CH4) emission is 20 times higher than that of carbon dioxide, and its ability to penetrate the ozone layer is 7 times higher. In order to maintain the living environment and protect the earth's atmosphere, human beings should put the development and utilization of coalbed methane on the agenda of 2 1 century, which will inevitably accelerate the development of coalbed methane industry.
In the process of global economic integration, environment and resources are both important propositions. China's economic development will also conform to the world trend and accelerate the development of clean energy, and natural gas will be the first choice. Evaluation and prediction of energy resources in China: the prospective natural gas resources are 38× 10 12m3, and the recoverable resources are10.5×10/2m3. 1997 China's natural gas output was nearly 2 10× 108m3/a, and it has been maintained at about 200× 108m3/a in recent years. The output in 2000 was 262× 108m3, and it is expected to reach 500× 108 m3 in 2005. In 20 10, the reserve is (5.1~ 5.6 )×10/2m3, and the output is (660 ~ 770) × 108m3/a, and the reserve in 2020 is (7. It is predicted that from 2000 to 2020, natural gas reserves will double and output will double, which is the stage of rapid development of natural gas industry. According to the forecast of China's national economy's demand for natural gas, the consumption of natural gas needs to increase by 50% ~ 100% in 20 10, double before 20 10, 20 1000× 108 m3 and 20/kloc-0. In 2020, China's natural gas demand will reach (1877 ~ 2088) ×108m3/a. The above data show that the natural gas demand predicted according to the national economic growth is far greater than the natural gas industrial output predicted by resources, which shows that the market potential for developing natural gas industry is huge.
Judging from the sudden emergence of coalbed methane industry in China, the breakthrough of exploration test was achieved before 2000, and it began to enter the regional exploration stage, initially completing the historical mission of preparation stage before high-speed development. It can be imagined that the year 2000 to 20 10 is the key period for the development of coalbed methane industry, which will start from the zero point of reserves and output and realize the development from1×108m3/a-1×108m3/a-/kloc. Achieving this goal is equivalent to the total output predicted for the development of natural gas industry (970 ~1200 )×108m3/a, and only in this way can we basically meet the needs of national economic development.
The potential of coalbed methane resources in China is huge, with the prospective resources of 20× 10 12m3, which is equivalent to (11.32 ~ 24 )×1012m3 in the United States and 240×/2m3 in the world. It is equivalent to half of China's prospective natural gas resources, that is, 38× 10 12m3. Therefore, from the perspective of resource conservation, it is fully qualified to realize the envisaged goal of high-speed development of coalbed methane industry at the beginning of 2 1 century.