Overview of Coalbed Methane Resource Development

(1) Current status of coalbed methane drainage in coal mining areas

Since the successful underground gas drainage test at Longfeng Coal Mine in Fushun Mining Area, Liaoning Province in 1952, underground coal mine gas drainage has been promoted to High gas mining areas across the country. At present, nearly 190 large coal mines across the country have established underground drainage systems and ground gas transmission and distribution systems. The annual drainage volume (pure methane) is increasing year by year. Among them, the annual drainage volumes of Fushun, Yangquan, Huainan, Jincheng and other mining areas have all exceeded 1×108m3. According to statistics, in 2004, key state-owned coal mines had 308 sets of surface coal mine gas extraction systems and 272 sets of underground mobile extraction systems, with a gas extraction volume of 18.66×108m3 and a extraction rate of 26.5%. The gas extraction volume of the 45 coal enterprises under key safety monitoring is 16.95×108m3. The mining areas with annual extraction volume exceeding 1×108m3 include Yangquan, Huainan, Shuicheng, Panjiang, Songzao, Jincheng, Fushun, etc. In 2005, the national coalbed methane extraction volume reached 23×108m3, and the total utilization volume exceeded 10×108m3. In 2006, there were 5227 high gas and coal and gas outburst mines in my country, of which 67 key state-owned coal mining enterprises had 286 high gas and coal and gas outburst mines. Coal and gas outburst mines. Among the 286 mines with high gas and gas outbursts in the former key state-owned coal mines, 264 mines actually carried out gas drainage, accounting for 92.3% of the mines with high gas and gas outbursts in the former key state-owned coal mines. In 2006, a total of 26.14×108m3 of gas was extracted from 286 mines with high gas and gas outbursts in key state-owned coal mines in my country. In 2008, the total gas extraction volume of underground coal mines nationwide was 50×108m3 (Figure 4-2).

Figure 4-2 Total gas extraction volume from key state-owned coal mines in my country from 2001 to 2007

(2) Current status of coalbed methane surface development

Since the 1990s Since the 1990s, as the U.S. surface development technology for coalbed methane has matured, my country has also actively carried out experiments in ground exploration and development of coalbed methane resources. It has successively included Shenyang Gas Company, Kailuan Mining Bureau, Jincheng Mining Bureau, former North China Petroleum Geology Bureau of the Ministry of Geology and Mines, China General Administration of Coalfield Geology and its subordinate provincial bureaus (Northeast Bureau, Shaanxi Bureau, Shanxi Bureau, etc.), Zhongyuan Oilfield , PetroChina Coalbed Methane Project Management Department, Xi'an Branch of Coal Research Institute, China United Coal Company and other enterprises have invested in the Qinshui Basin, Hedong Coalfield, Anhui and Lianghuai areas, and Tiefa, Kailuan, Shenbei, Hongyang, Dacheng, CBM exploration and development tests have been carried out in Fengfeng, Anyang, Xingyang, Hancheng, Fengcheng, western Guizhou, eastern Yunnan, Hongshandian, Lengshuijiang and other mining areas. As of 2008, my country has drilled approximately 3,400 coalbed methane wells of various types, resulting in a surface coalbed methane production capacity of approximately 20×108m3. Among them, the most representative coalbed methane surface development and commercialization projects are:

(1) Shanxi Qinshui Zaoyuan well group coalbed methane development test project: There are 15 existing coalbed methane production test wells with daily compression The small CNG compression station with a capacity of 3.6×104m3 and the small coalbed methane power station with a daily power generation of 400kW have realized the commercial development, gathering, transportation, storage, transportation and utilization of small-scale coalbed methane.

(2) Coalbed methane development project in the Liujiajing Formation in Fuxin, Liaoning: The Fuxin project drilled 8 wells in the Liujiajing Coalfield in Fuxin from 1999 to 2001, forming a small well network. The average gas production of a single well is more than 3000m3/d.

(3) Shanxi Jincheng Sihe coalbed methane ground pre-pumping project: This project began in 1992. Jincheng Mining Bureau cooperated with the US-China Energy Company to construct 7 coalbed methane ports in the Panzhuang area. Production test well. After more than 10 years of drainage and extraction, it has not only proved that the coalbed methane resources in Panzhuang area have good recoverability, but also accumulated experience for the region and even the country. By the end of 2007, the project had completed the drilling of 156 vertical wells and 6 multi-branch horizontal wells. 150 vertical wells and 6 multi-branch horizontal wells were in production. The average daily production of a single vertical well was 2000m3. The average daily production of a single well is 5×104m3 (the maximum daily production is 10×104m3), and the annual coalbed methane production capacity has been initially achieved at about 2×108m3. The project has built a complete gathering and transportation pipeline network, gas gathering station and compression station.

(4) Shanxi Qinnan Coalbed Methane Development and Utilization High-tech Industrialization Demonstration Project—Panhe Pilot Test Project: This project is a national high-tech industrialization project for coalbed methane development and utilization approved by the National Development and Reform Commission. Demonstration project. The project plans to construct 900 coalbed methane wells, which will be completed in three phases.

The first phase of construction of 150 coalbed methane production test wells was completed in 2006. A coalbed methane production demonstration base with an annual coalbed methane production of approximately 1×108m3 will be built; in the second phase, 400 coalbed methane production wells are planned to be constructed, with a production capacity of 4×108m3/a; in the third phase, 350 coalbed methane production wells are planned to be constructed, with a production capacity of Up to 7×108m3/a.

In addition to the above-mentioned commercial demonstration projects, the Daning-Jixian project, Hancheng and other projects are also conducting well group production tests.

(3) Current status of coalbed methane utilization

1. Current status of coalbed methane utilization in surface development

The coalbed methane produced in surface development has a high methane concentration and can be mixed with natural gas. For mixed use. In recent years, the output of coalbed methane from surface mining in my country has been very small, which has restricted the utilization of coalbed methane. Currently it is mainly used for residential gas, automobile fuel and special industrial gas.

The coalbed methane produced by the Zaoyuan well group in Qinshui, Shanxi, in addition to supplying power generation to the self-contained gas power station (to meet the electricity consumption of the well group), has been supplied to Changzhi City, Shanxi Province through CNG tanker transportation since 2003. It is used by some residents in Linzhou City, Henan Province, and the supply volume is about 5000m3/d.

The coalbed methane produced by the Liujiajing Formation in Fuxin, Liaoning Province was supercharged and then input into the Fuxin City urban natural gas pipeline network. In March 2003, it began to supply gas to urban residents, with a daily coalbed methane supply of 1.6×104m3.

Since the coalbed methane produced by the Jincheng Sihe coalbed methane ground pre-pumping project began to replace domestic gas within the group company in 2004, more than 20,000 employees have used coalbed methane. Gas supply to Jincheng City began in 2005. Jincheng Glass Factory and Ceramic Factory have used coalbed methane to replace liquefied petroleum gas or water gas. About 1,000 taxis and buses have switched to using coalbed methane as fuel. 1m3 of coalbed methane can replace 1.13l Gasoline, while the former sells for less than half of the latter [83].

The Panhe Coalbed Methane Pilot Development Demonstration Project has built 1 CNG filling station, 1 gathering and transportation station, 1 gas power station and gas transmission pipeline network. In 2005, it began to supply gas to Handan City in Hebei Province and Linzhou City in Henan Province.

Using coalbed methane to generate electricity has significant benefits: 1m3 of gas with 100% content can generate 3.2 to 3.3kW·h electricity, and 1m3 of gas with 30% content can generate 1kW·h of electricity. Jinmei Coal Group built a gas power generation pilot plant with an installed capacity of 1.5×104kW using the gas extracted from the Sihe Mine. In winter, waste heat is used to heat the mining area and achieve cogeneration of heat and power, forming a closed-circuit polygeneration cycle. The plant was put into operation in 2001. By the end of 2005, it had generated a total of 3.3×108kW·h and achieved an output value of 117.59 million yuan [84].

2. Current status of underground coalbed methane extraction

The gas extraction volume of key state-owned coal mines in my country is increasing year by year (Figure 4-2), and the utilization volume is also increasing. For example, a 112×104m drainage pipe network was installed underground in the Sihe Mine of Shanxi Jincheng Anthracite Mining Group, and 16 drainage stations were built. The total drilling footage exceeded 3×104m, and the annual drainage volume reached 7000×104m3 (equivalent to pure methane). There are 4×400kW gas generators and 2×2000kW coalbed methane power stations. Many mines such as the adjacent Yonghong Coal Mine have built self-contained coalbed methane power stations that use underground coalbed methane as fuel. Yangquan Coal Industry Group has more than 12×104m of underground coalbed methane drilling holes, and the annual coalbed methane extraction volume is 1.12×108~1.15×108m3. It has 3 gas storage tanks and 64km of gas transmission pipelines, supplying gas to 120,000 households. The 5×104t coalbed methane-to-methanol project and the 111×104kW coalbed methane power generation project have been approved by the Shanxi Provincial Development and Reform Commission. Shanxi coalbed methane utilization projects using ADB loans (including Jincheng Anthracite Mining Group's Sihe underground coalbed methane drainage project, 12×104kW coalbed methane power generation project, internal power grid transformation project, Jincheng city gas project and Shanxi Energy Industry Group Co., Ltd. The company's gas pipeline project) has been fully launched. The total investment of this project is about 2 billion yuan, which is currently the largest underground coalbed methane extraction and utilization project in China [85].