In Situ Enhancement and Isotopic Labeling of Biogenic Coalbed Methane

Area of Science:

• Geosciences
• Microbiology
• Environmental Science

Background:

• Subsurface microbial methane production is crucial for the global carbon cycle and natural gas formation in coal beds.
• Laboratory studies indicate nutrient enrichment can stimulate methane production, but in-situ effectiveness in coal beds remains unconfirmed.

Purpose of the Study:

• To investigate the in-situ effectiveness of yeast extract (YE) in stimulating biogenic methane production in coal beds.
• To utilize isotopic labeling and advanced monitoring to quantify methane enhancement.

Main Methods:

• Injection of 0.1% yeast extract (YE) and deuterated water (D2O) into a coal bed.
• Real-time gas pressure monitoring using a total dissolved gas pressure sensor.
• Collection of downhole samples with subsurface environmental samplers for isotopic analysis.

Main Results:

• Methane levels increased by 132% (isotopic labeling), 108% (pressure readings), and 183% (direct methane measurements) 266 days post-injection.
• Demonstrated successful stimulation and isotopic labeling of newly generated methane in situ.
• Validated multiple novel measurement methods for tracking microbial activity and methane turnover.

Conclusions:

• Yeast extract (YE) effectively enhances in situ biogenic coalbed methane production.
• The study provides a framework for field-scale investigations of microbial methane enhancement.
• Highlights the potential for in situ detection and tracking of microbial methanogenesis in recalcitrant carbon turnover.