❓ How to identify areas suitable for coal seam methane extraction?
Methane from coal seams is a promising unconventional energy source. However, unlike conventional gas deposits where gas is trapped in reservoirs, here it is dispersed over vast areas. And not every site is suitable for commercial production.
A scoring system is used for assessment, combining 10 key factors: permeability, desorption, methane content, resource density, volatile matter yield, moisture content, and others. Each factor is rated on a scale from –10 to +10 points.
Key patterns identified:
🔹 Gas content increases with depth following an S-shaped curve (Langmuir equation). At depths exceeding 600 m, methane content reaches 25–27 m³/t.
🔹 Permeability decreases with depth: at 250–300 m – 10–15 mD, at 600–700 m – hundredths and thousandths of a millidarcy.
🔹 Sorption capacity of coals depends on petrographic composition – correlations with fusinite content and temperature have been established.
🔹 Host rocks also contain methane: in argillites and siltstones with dispersed coal matter – up to 4–5 m³/t of rock.
Ranking example (Karaganda basin, total score):
🥇 Sherubainurinsky – 38
🥈 Saransky – 34
🥉 Taldykuduksky – 32
4️⃣ Promyshlenny – 31.9
5️⃣ Tenteksky – 29
The Sherubainurinsky site leads due to high resource density, methane content, and volatile matter yield, but lags behind others in desorption and moisture content.
Why this matters:
The scoring system allows quantitative comparison of sites and prediction of methane production efficiency at the planning stage. The answer to the question in the title: the higher the total score, the more promising the site.
📖 Read more:
Mussin R.A., Nemova N.A., Akhmatnurov D.R., Zamaliyev N.M., Reshetnyakov E.D., Reznik A.V. Justification of the prospects for developing gas-bearing sites in the Karaganda coal basin. Mining Science and Technology (Russia). 2025;10(4):321–337. https://doi.org/10.17073/2500-0632-2025-06-425
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