Experimental study of coalbed methane thermal recovery

Abstract

Extracting coalbed methane is challenging due to the strong gas adsorption capacity and low matrix permeability of the coalbed. Recently, thermal recovery methods have been tested to promote methane recovery. In this study, anthracite samples were heated to different temperatures to investigate the internal pressure variation and microstructure changes. It was found that higher temperature resulted in higher internal pressure. At low temperatures, the increase in the internal pressure was mainly due to gas desorption. At 500°C, thermal cracking gases provided the main contribution to the high internal pressures, as more gaseous products were generated at the higher temperature. In addition, the microstructure of coal significantly changed after combustion, including the increased pore volume, the increased specific surface area, and the generation of microfractures. These changes could potentially increase the porosity and permeability of coal. Thus, high‐temperature thermal treatments not only provided energy for gas desorption and organic matter decomposition but also improved conditions for gas transport.

Quantifying Organic Matter and Its Pore Structure of Wufeng–Longmaxi Deep Shales by Small-Angle X-ray Scattering, Mercury Intrusion Capillary Pressure, and Field-Emission Scanning Electron Microscope

“…Being the main component of depositional OM, kerogen is often considered a part of the shale matrix framework and thus is directly subjected to the pressure exerted by overlying strata. , Although a high pore pressure and sealing ability can resist the pressure exerted by the overlying formation, compaction becomes more intense as the burial depth increases, and the strong physical–chemical structural changes that occur in shale make it difficult to identify the OM components. , Therefore, the kerogen morphology is generally incomplete and is characterized by poorly developed pores (Figure a), strong heterogeneity (Figure b), and an irregular shape (Figure c). However, the residual OM still maintains its biological structure, which has bands or a particular shape (Figure ), and shows different anisotropy strength in the compaction direction.…”

Coalbed Methane Potential of Pakistan-A Review

“…For accurate calculation of gas production and recovery, the moisture content effect is incorporated in different directions of reservoir properties. Sorption rate, gas diffusivity, and gas adsorption decrease with an increase in moisture content (Cao et al 2020). This is because water molecules occupy large spaces, leaving less volume for gas residence (Pan et al 2010;Li and Zhang 2014).…”

Evolution of Shale Microstructure under in Situ Heat Treatment: Synchrotron Small-Angle X-ray Scattering

“…24,25 Electromagnetic heating has also been used to stimulate coalbed methane reservoirs. 26 On stimulation of shale reservoir physical properties, Chen et al 21 analyzed the influence of temperature on shale permeability. Yang et al 27 conducted an experimental study on the wettability of shale at different temperatures.…”

“…Heat treatment technology has been widely used in petroleum engineering. In oil shale and asphalt sand, hot steam or resistance heating treatment is often used to reduce the viscosity of heavy oil and increase the fluidity of oil. , Electromagnetic heating has also been used to stimulate coalbed methane reservoirs . On stimulation of shale reservoir physical properties, Chen et al analyzed the influence of temperature on shale permeability.…”