(Northeast Coalfield Geological Bureau 107 Exploration Team Fuxin 123000)

Author's brief introduction: Zhang Junbao, professor, researcher-level senior engineer, mainly engaged in coalfield geology, coalbed methane geology and other related geological work. In recent years, he has published five academic papers on coalbed methane and geothermal energy in national journals.

On March 1 March, 2003, the surface mining and underground drainage of coalbed methane in Fuxin City, Liaoning Province officially supplied gas to the urban area, realizing the commercial development of coalbed methane. According to the actual situation of surface mining of coalbed methane in Liujia District and mine gas drainage in Fukuang Group, the present situation and prospect of development and utilization are discussed.

Surface mining of coalbed methane; Commercial development of coalbed methane extraction in mines

Present situation of development and utilization of coalbed methane in Fuxin City, Liaoning Province

Zhang Junbao, he is in Mei.

(Northeast Coalfield Geological Bureau/team KLOC-0/07, Fuxin 123000)

The ground development and underground extraction project of coalbed methane located in Fuxin City, Liaoning Province officially supplied gas to the public on March 6, 2003, realizing the commercial development of coalbed methane in this area. Based on the actual situation of surface coalbed methane development project in Liu Jia area and underground gas extraction project of Fuxin Coal Industry Group, this paper probes into the present situation and prospect of local coalbed methane development and utilization.

Keywords: coalbed methane; Surface mining; Underground mining; Commercial development

introduce

Fuxin is located in the west of Liaoning Province, between Shenyang and Jinzhou. In March 2003 1, coalbed methane was mined on the ground in liujia district and pumped down in Fuxin mining area, and the daily gas supply scale was (8 ~12) ×104m3 (34% CH4), thus ending the history of Fuxin residents burning coal to make gas in 17 years, with a history of 6. After nearly four years of operation, it shows that the gas supply is stable, safe and reliable. The development and utilization of coalbed methane, marked by surface drilling coalbed methane mining (CBM) and mine CBM extraction (cmM), has achieved industrialization, ranking first in the country.

1 CBM exploration background

The geological work of coalbed methane in Fuxin city was earlier. From 65438-0996, the Northeast Coalfield Geology Bureau 107 team submitted the report "Occurrence Conditions of Coalbed Methane in Fuxin Coalfield" for Sino-American Coalbed Methane Company. On the basis of data analysis and research, the resource conditions of coalbed methane in Fuxin basin are evaluated, and Liujia area is proposed as the key area for coalbed methane development.

Liujia District is located in the middle of Fuxin coalfield, and the coal seam belongs to Fuxin Formation of Lower Cretaceous. According to the survey report of 1993, the coal reserves are 28 195× 104t, the natural coke reserves are 6223× 104t, the buried depth of coal seam is 600 ~ 1000m, and the maximum cumulative thickness of coal seam is about 98m. Coal is mainly long-flame coal. 1998-200 1, invested by the state and Liaoning province, the northeast coalfield geological bureau 107 team carried out the general survey and exploration of coalbed methane in liujia district, and * * * constructed 4 coalbed methane parameters and test wells. After the drainage test, the daily output of a single well is as high as 6000m3, with an average of about 3000m3, and the methane content is about 98%, indicating that the area is good. On 200 1, the team of northeast coalfield geology bureau 107 submitted the report of coalbed methane survey in liujia district, Fuxin city, Liaoning province, which was approved by China coal geology bureau. The CBM resources in the whole region are 52.171×108m3, of which the controlled resources are 32.289× 108m3 and the prospective resources are 60.

In 2002, Fuxin invested in the construction of 4 CBM production wells in this block, forming 8 CBM well patterns. On March, 2003, Kloc-0/officially supplied gas to urban areas, with an average daily gas supply of about 2× 1 04m3, realizing commercial development and being the first case of surface coalbed methane mining in China.

2 mine coalbed methane extraction system

At present, Fu Mine Group owns eight mines, including three high gas mines (Wulong Mine, Qinghemen Mine and Haizhou Vertical Shaft), two outburst mines (Aiyou Mine and Wangying Mine) and three low gas mines (Yima Mine, Wulong Mine and Badaohao Mine). According to the assessment of Fushun Branch of Coal Science Research Institute 1997, the coalbed methane reserves reach116.06×108m3, including 66.34× 108m3 in Wulong Mine, Liujia District and Haizhou Vertical Shaft and 24.866 m3 in Wangying Mine. Aiyou Mine is11.98×108m3, Qinghemen Mine is 12.93× 108m3, and the gas content is10 ~12m3. According to the analysis of coalbed methane occurrence, the gas source is sufficient.

The coal-bed methane drainage of Fukuang Group started in 1993, and a set of coal-bed methane drainage and utilization system was built in Nanfengjing of Wangying Mine, and gas supply was realized to Fuxin Fluorine Chemical General Factory in June of 1997. The project of comprehensive utilization of residential gas was approved by Liaoning Provincial Planning Commission 1999 in June 2006. The project started construction in April 2000 and was fully completed on September 29, 2006. In March 2003, 1 supplied gas to Fuxin citizens.

At present, six of the eight mines have successively established, reformed and improved the ground or underground gas drainage system. Five mines (Wulong Mine, Aiyou Mine, Qinghemen Mine, Evergrande Company and Haizhou Vertical Shaft) have built six sets of permanent ground gas drainage systems, and some mines have also built underground mobile drainage systems. The basic method of gas drainage is a comprehensive drainage method, which is mainly based on the gas drainage channel of high roof or adjacent layers, supplemented by horizontal long drilling holes in high drilling field and buried pipes in goaf.

3 Development and utilization status

Fuxin has jurisdiction over two counties and five districts. Among them, Haizhou District is a popular area for gas. Qinghemen Beishan area is about 45 kilometers away from the urban area, which is an independent area. Municipal facilities are underdeveloped, so far, there is no gas supply system in this area. In 2003, the actual gas supply was 506× 104m3(CH434%, 1489× 104m3), of which:  General Fluorine Chemical Factory:100×104m3 (ch 434). Actual gas supply in 2004: 6 17× 104m3(CH434%,1816×104m3), of which:  Fluorine Chemical General Factory: 55×/kloc-0.

At present, due to the small amount of utilization, only limited drainage can be carried out under the condition of meeting the requirements of safe ventilation underground. Wulong, Wang Ying and Aiyou No.3 Mines * * * extracted 8.82× 104m3/d of pure coalbed methane, and part of it was used to supply gas to the municipal fluorine chemical general factory (0.34× 104m3/d of the municipal fluorine chemical general factory, mixed gas volume 10000m3/d, and 6500 m3/d of the municipal gas plant).

At present, the surface coal-bed methane mining in Liu Jia is mainly for urban use, and the average gas production is (1.5 ~1.7) ×104m3/d (ch498%). In April 2005, Fuxin Gas Plant changed taxi oil to gas. At present, about 500 taxis have switched to coalbed methane. After 1 years of operation, the effect is very good, and the daily gas consumption is about1×1.04m3.

4 Next step plan

4. 1 gas planning

4. 1. 1 city gas planning

Gas consumption of residents in Fuxin: In recent years, due to the development of urban economic construction, the number of gas users in urban areas has increased year by year. According to the statistics of Fuxin Gas Company, the annual gas consumption has increased by about 7%. According to the needs of urban development, Fuxin Gas Plant specially compiled the gas consumption schedule for Fuxin urban area from 2004 to 20 15. See table 1 for details.

Table 1 Fuxin Natural Gas Consumption Schedule

4. 1.2 industrial gas

According to the needs of the revitalization and development of the old industrial base in Northeast China and the economic transformation of resource-exhausted cities, the demand for clean energy in Fuxin local industries will further increase. The main gas supply direction of this project is planned to be Fuxin Glass Factory and Fuxin Fluorination Factory.

The planned gas supply capacity is: the coalbed methane from the drainage system in Liujia District of Wangying Mine and Wulong Mine and the open-pit mining system in Liujia District will be transported to the gas storage tank, a 5.4× 104m3 transmission and distribution station, and then pressurized and transported to Fuxin Fluorine Chemical General Factory and Fuxin Glass Factory, with a total gas supply capacity of 10.87× 104m3/d, 399. After mixing, the CH4 content is 55% and the calorific value is 4680kcal/m3. After mixing, the daily gas supply is 19.92× 104m3, and the annual gas supply is 727 1× 104m3.

4.2 Gas supply planning

4.2. 1 coalbed methane extraction in mining area

According to the relative position of each mine and the available conditions around it, Fukuang Group plans to extract coalbed methane from Haizhou Vertical Shaft, Wulong Mine, Liujiaqu Mine, Wangying Mine, Aiyou Mine and Qinghemen Mine.

According to the analysis of coalbed methane resources, mining conditions and coalbed methane extraction conditions of Fukuang Group, and according to the requirements of gas supply agreement signed with Fuxin Gas Company and gas supply agreement for industrial users, the project construction scheme is determined as follows:

With the production of the working face, the total capacity of coalbed methane extraction in each mine is11.69×104m3/d, and the converted mixed gas is 34.4× 104m3/d(34%CH4). See Table 2 for the underground coalbed methane drainage plan of Fukuang Group.

Table 2 Underground Drainage Schedule of Coalbed Methane in Fu Mine Group

4.2.2 Surface drilling to exploit coalbed methane

According to the practice of Geological Bureau of Northeast Coalfield in Liujia District 107 Team 1998 ~ 2002, the average single-well gas production is 3,000 ~ 5,000m3/d. It is estimated that 22 surface boreholes of coalbed methane will be built in Liujia area, and the recovery rate of coalbed methane per single well is 3,000m3/d, and the recoverable coalbed methane is 6.6×/kloc-respectively. The drilling quantity and completion technology will be further adjusted according to actual needs. It is predicted that the service life of coalbed methane wells is 10 ~ 15 years. After 10 ~ 15, due to the need of coal mining, some coalbed methane boreholes can be converted into mine goaf drainage boreholes. If the goaf is well sealed underground, the predicted methane concentration can reach 70% ~ 90%. CBM drilling can also serve for 5-20 years, which can meet the requirements of project planning and market planning.

In addition, according to the current coal mining situation of each production mine, the ground drilling construction of coalbed methane can be carried out in the unexploited block, so as to achieve the effect of gas production first and then coal mining.

5 conclusion

The present situation and next step planning of coal bed methane development and utilization in Fuxin city are briefly described above. In fact, the current mining scale is far from meeting the market demand. At present, there are about 200,000 residents in Fuxin, but only 65,000 residents use gas, and two thirds of them don't use gas. At present, Fuxin Glass Factory has completed the second phase reconstruction project. The three kilns need 32× 104m3 of coalbed methane, and the daily calorific value is 5000 cal/g. Increasing the production scale can not only meet the market demand, bring greater economic benefits, but also reduce the harm caused by gas to coal mine production.