Coalbed Methane Resource Assessment and Development

Coalbed methane (CBM) is an unconventional natural gas held within micro-porous coal seams and cleat systems, released by desorption when reservoir pressure falls. Resource assessment integrates geological mapping, seismic surveys, well logging and geomechanical modelling to estimate gas content, porosity, permeability and producibility. Quantitative methods—such as multi-criteria evaluation, geostatistical simulation and reservoir fluid flow modelling—support the delineation of high-potential zones and critical depth intervals. Development of CBM requires tailored drilling and completion strategies, including vertical, directional and multibranched horizontal wells, alongside reservoir stimulation by hydraulic fracturing or gas-enhanced recovery such as CO₂ injection. Advances in drilling tools, measurement-while-drilling and underbalanced techniques have improved well placement and formation evaluation. Completion technologies—from open-hole cavity designs to screen-pipe and under-reamed configurations—enhance drainage efficiency. Concurrently, water-management practices and geostress analysis mitigate environmental impacts and ensure safe production. Globally, CBM offers a cleaner-burning alternative to coal, provides mine safety benefits by reducing gas hazards, and contributes to energy diversification in coal-rich regions.

Research from Nature Portfolio

Recent studies have established a systematic framework for evaluating deep CBM recoverability by optimising key geological parameters such as coal seam thickness, reservoir pressure, permeability and in situ stress. Employing a multi-fuzzy logic approach, researchers have quantified resource and development conditions across coal seams and classified areas into hierarchical recoverability levels. This classification highlights Class A zones with the most favourable combination of reservoir quality and development potential, while deeper Class III zones are identified as targets for exploratory drilling and future exploitation.

Coalbed Methane Resource Assessment and Development publication trend

The graph below shows the total number of articles in coalbed methane resource assessment and development across all publications each year (not limited to Nature Index journals).

Technical terms

Adsorption: The process by which methane molecules adhere to the internal surfaces of coal micropores under reservoir pressure conditions.

Permeability: A measure of the ability of a coal reservoir to transmit fluids through its pore network or cleat system.

Geostress: The in situ distribution of vertical and horizontal stresses within the earth’s crust that governs fracture propagation and reservoir behaviour.

Hydraulic fracturing: A stimulation technique involving the high-pressure injection of fluid to create or extend fractures in coal seams, thereby enhancing gas flow pathways.

References

1. Evaluation of recoverable potential of deep coalbed methane in the Linxing Block, Eastern Margin of the Ordos Basin. Scientific Reports (2024).
2. Drilling and completion technologies of coalbed methane exploitation: an overview. International Journal of Coal Science & Technology (2022).
3. Hydrodynamic and Geostress Controls on CBM Enrichment in the Anze Block, Southern Qinshui Basin, North China. Geofluids (2022).