Study of the CO2 ECBM and sequestration in coalbed methane reservoirs with SRV

• The CO2 and CH4 displacement experiments were conducted using two different methods.
• Three numerical simulation models of 5-point well groups with SRV were built.
• Influence factors of CO2 storage and ECBM are analyzed.
• The method of “desorption/gas injection/desorption” is suitable for CO2 replacing CH4.
• The SRV measures can increase the single well productivity of CBM.

Stimulated reservoir volume (SRV) and CO2-enhanced coalbed methane recovery (ECBM) are two popular technologies used to develop coalbed methane (CBM) reservoirs. Anthracite coal samples were selected from the CBM reservoir in the southern part of Qinshui Basin. The CO2 and CH4 displacement experiments were conducted using two different methods, “gas injection/desorption” and “desorption/gas injection/desorption”. Based on the indoor experiment, and using the reservoir geological properties, fluid properties and stimulated measure data of the target CBM reservoir, three numerical simulation models of 5-point well groups with SRV were built. These models were used to conduct influence factor analysis of CO2 storage and ECBM in the volume stimulated CBM reservoir. Using the above indoor experiments and numerical simulation experiments, the following conclusions were obtained: the method of “desorption/gas injection/desorption” is more favorable for CO2 replacing CH4 and realizing CO2 storage and ECBM. The SRV measures can increase the flow conductivity and improve the single well productivity of CBM. The SRV size, SRV flow conductivity and gas saturation of the cleat system are the key influence factors of CO2 storage and ECBM in volume stimulated CBM reservoir. The study described in this paper can offer technical support for implementing the synthesis technologies of SRV and CO2 ECBM and storage in CBM reservoirs.