China's 100 billion cubic meters of "wasted" coalbed methane resources are expected to be released

In the list of 2020 Shanxi Provincial Science and Technology Award Projects announced recently, the project "Research and Demonstration of Surface Coalbed Methane Extraction Technology in Goaf of Abandoned Mine" won the first prize of scientific and technological progress. The project has carried out in-depth research on the enrichment of coalbed methane in the goaf area of abandoned mines, resource evaluation and well location optimization, formed a complete set of surface extraction technology and technology system, and built more than 100 extraction wells through the promotion and application in Jincheng, Xishan, Yangquan and other mining areas, and extracted and utilized more than 100 million cubic meters of coalbed methane.

Coal is the main energy source in China, and after long-term mining, there are a large number of goafs and abandoned closed mines, and there are huge coalbed methane resources. According to the forecast of the Chinese Academy of Engineering, by 2030, there will be 15,000 abandoned mines in China, and nearly 500 billion cubic meters of unconventional natural gas will be stored. The Guiding Opinions on Promoting the Comprehensive Treatment and Utilization of Coal Mine Gas (Draft for Comments) issued by the National Energy Administration in May 2020 clearly points out that "after the closure and withdrawal of coal mines, the residual coal mine gas in the mine is easy to cause secondary disasters, threatening the safety of surrounding production and life, and increasing greenhouse gas emissions." "If the coalbed methane in the abandoned and closed mine is not used, it will continue to escape from the underground to the surface through various fractures, which not only pollutes the environment, but also has many safety accidents, which is a huge environmental and safety hazard.

It is understood that coalbed methane, as a strong greenhouse gas, the greenhouse effect after escape is 21 times that of carbon dioxide, and the utilization of coalbed methane in the goaf area of the current abandoned mine in our province is 128 million cubic meters, which is equivalent to reducing carbon dioxide emissions by 1.92 million tons. Therefore, the scientific and effective extraction and utilization of coalbed methane (gas) in coal goafs and closed mines can not only eliminate the potential safety hazards caused by gas accumulation in abandoned mine goafs, but also "turn waste into treasure" of waste resources, and create a new source of "carbon emission reduction" for the coal industry to achieve the goal of "carbon peak and carbon emission reduction".

The "Research and Demonstration Project of Surface Coalbed Methane Extraction Technology in Goaf of Abandoned Mine" is a key coal-based scientific and technological research project in Shanxi Province, which is jointly tackled by the State Key Laboratory of Coal and Coalbed Methane Co-production of Jinneng Holding Group, Blue Flame Coalbed Methane Company of Huaxin Gas Group, China University of Mining and Technology (Beijing) and Taiyuan University of Technology. After several years of joint research and development, a relatively mature technical system has been formed in the aspects of coalbed methane drilling technology, pumping technology, equipment research and development, and gas utilization in the goaf area of abandoned mines, and a local standard of Shanxi Province has been formulated and promulgated to fill the gap in China. In recent years, the daily output of a single well has reached up to 8,000 cubic meters, and the average methane concentration of extraction has been maintained at more than 50% and up to 99%, which has a strong demonstration effect and promotion significance for the development of coalbed methane in abandoned mines and goafs in China.

The reporter learned that compared with general coalbed methane mining, coalbed methane extraction in abandoned mines and goafs has the advantages of low development cost, few construction links, and fast production capacity release, and has considerable commercial development value. With the continuous breakthrough of this technology, it will play a positive role in promoting and supplementing the construction of a national unconventional natural gas base in our province and the vigorous implementation of coal-to-gas reserves and production.

Disclaimer: The above content is reprinted from Shanxi News Network