Degassing is a set of works for the extraction of gas from coal seams (beds)

Degassing is a set of works for the extraction of gas from coal seams (beds), which in high concentrations represents a danger to the health and life of mine workers, which can lead to an explosion and the collapse of the rock. The coal industry uses the following types of degassing:

• Advance or early degassing;
• Enveloping;
• Preliminary;
• Front-end.

The degassing can be passive and active, the difference lies in the use of special vacuum equipment for gas extraction. Novas ES offers an innovative method of degassing, based on the technology of plasma-pulse treatment (PPT) of the coal seam, carried out through vertical wells 3-8 years before the start of mining operations. This technology has been successfully tested in Russian mines and provides the most complete transfer of gas into a free state while maintaining the integrity of the reservoir.

Coal degassing methods

As the depth of the mine increases, the geological conditions of the work become more and more complicated, the cost of standard degassing works increases, the complexity of gas removal process monitoring grows. At present, conventional yield enhancement technologies are widely used in Russia, related to the use of hydraulic fracturing methods and the drilling of additional wells, that often provide the results that are far from satisfactory. The solution is the creation of an efficient system for early degassing of coal beds. All present gas can be transferred into the free state by the use of two methods:

• Dispersion of the coal;
• Creation of a network of anomalous cracks.

At the same time, it is important to preserve the integrity of the formation which can only be reached with the use of plasma-pulse generator.

Specifics of PPT method for coal seam degassing

Currently, the PPT technology is widely used for well development, to increase the yield, injectvity, permeability for purpose of oil production enhancement. The main principle of the method is as follows:

• The generator of plasma-pulse action is a source of oscillations and delivers a high voltage current to the electrodes closed by a metal conductor;
• The metal conductor explodes and creates plasma in the enclosed space;
• The explosion forms the shock wave, which greatly influences the coal beds;
• The rock periodically shrinks and stretches, which is accompanied by the release of gas bubbles;
• A network of anomalous microcracks is created in the formation, contributing to maximum gas evolution.

Plasma-pulse treatment of the coal seam is produced using modern equipment and is the most effective method of degassing that allows to ensure safe conditions of coal production even under high loads.

The advantages of plasma pulse treatment

The method of plasma-pulse treatment of coal bed has several clear advantages:

• It is ecologically impeccable;
• Support from Skolkovo foundation;
• High efficiency;
• It can be used in any conditions;
• Safety of operations;
• Affordability and mobility.

This is a universal technology, which is especially well-tested in low-permeability oil & gas reservoirs worldwide.