Two methods are used on the Eastern Gas Shales Project to measure the gas volume of encapsulated shale samples. The direct method measures pressure and volume and is initiated almost immediately upon encapsulation of the sample. A second method measures pressure, volume, and composition, and is initiated after pressure is allowed to build up over several weeks. A combination of the two methods has been used on selected samples, and yields more data as it allows extrapolation to account for gas lost prior to encapsulation. The stratigraphic horizons, characterized by dark shales with high organic and high carbon content and a relatively high gamma ray intensity of 200+ API units also have high gas contents (relative to other units within the same well). The Lower Huron, Rhinestreet, and Marcellus Shales are high in gas content relative to other stratigraphic units at the same sites. The difference in gas content of the same stratigraphic horizon between well sites appears to be controlled by the thermal maturity. Kinetic studies have shown that, in some samples, significant amounts of gas are released after the time when the gas volume would be initially measured. Additional work needs to be performed to determine why the rates and volume of gas released vary between samples.
- .PDFEGS-Eastern Gas Shales Project Outgassing Analysis- Special Repo.pdf