The technology for the extraction of methane from coal seams allows for early degassing from the surface at the mine design stage, 5-7 years before the start of operations when the methane content in the coal seam is at its maximum.
The use of technology at the stage of stripping and preparation of the mine, 3-5 years before the start of coal mining, allows to reduce the gas content in advance to a safe level in the zone of future lava. Plasma-pulse treatment is conducted through wells drilled from the surface in future collapse domes, which are used for traditional dome degassing.
Advantages of advance degassing
Low cost
Significantly lower than hydraulic fracturing
Repeatability
Can be used multiple times in one well.
Selectivity
The treatment interval is selected with an accuracy of 5 cm
Environmental friendliness
Chemical reagents are not used, minimum environmental impact
High recoverability
Elegant, accurate, directed impulse to the carbon matrix (in volume) as a factor in increasing recoverability
Cost structure: project "Advance degassing of coal lava using PPT technology",%
The most effective is the use of PPT technology for coal seams with a high natural gas content (>15m3/t), due to the need to perform a long set of activities for traditional degassing: reservoir, dome, barrier degassing, carried out in coal mines, where ventilation cannot ensure the content of methane in the air within the safety standards in accordance with federal laws.
The economic effect of the work on advance degassing offered by LLC "Georezonans" is the following:
- reducing the time of preparation and commissioning of coal lava;
- increasing the load on the lava and accelerating mining operations in coal seams with high natural gas content;
- reducing the cost of traditional degassing - the use of wells for domed degassing, reducing the volume of reservoir and barrier degassing;
- the possibility of efficient utilization of produced methane. Captured methane from degassing wells can be utilized efficiently (methanol, electricity, etc.) because pure methane is being extracted (the content of CH4 is 97.4% on the basis of laboratory tests) and it does not require additional purification.
The payback period depends only on the required period for degassing to the planned level of gas content and the launch of coal lava into operation. With the launch of degassed coal lava, all costs incurred pay off in 7-14 days.
All of the above activities are calculated as the costs associated with providing safe conditions and labor protection in coal mining, so during the project, all activities are combined into a single agreement on advance degassing, which allows the mining company to declare 100% of the costs incurred to be deducted from mineral extraction tax in accordance with the Decree of the Government of the Russian Federation No. 455 dated 10.06.2011.
Mine, being a site of hazardous labor conditions, is forced to seek a balance between safety and performance. The use of advance degassing using the PPT method allows, on one hand, to significantly increase the safety of miners, and on the other, to increase the penetration rate by 10% - 50%. Thus, the use of advanced degassing using the PPT method allows to avoid contradiction when choosing between safety and performance.
The use of combined schemes with the advance and ongoing degassing - the efficiency of methane extraction up to 80%. In the period from October 2014 to October 2016 research and pilot works were carried out on the early degassing of coal beds 48 and 45 in the contour of lava 48-5 and 48-6, 4 wells drilled from the surface penetrated the future collapse domes, at the Erunakovsky Vostochny site, at the Erunakovskaya-VIII mine of LLC EvrazHolding. During the period of operation, 1 million 119 thousand m3 of methane was extracted.