ABSTRACT
If shale rock is a capable source rock, there is potential for it to store economic quantities of gas. The potential of a shale formation to contain economic quantities of gas can be evaluated by identifying specic source rock characteristics such as total organic carbon (TOC), thermal maturity, and kerogen analysis. Together, these factors can be used to predict the likelihood of the prospective shale to produce economically viable volumes of natural gas. A number of wells may have to be analyzed in order to sufciently characterize the potential of a shale formation, particularly if the geologic basin is large and there are variations in the target shale zone. Total organic carbon, thermal maturity, and kerogen analysis are important gas shale characteristics, and it is essential to have an understanding of these parameters:
• Total organic carbon (TOC) is the remnant of ancient life preserved in sedimentary rocks, after degradation by bacterial and chemical processes and further modied by temperature, pressure, and time or thermal maturation. The latter step, thermal maturation, is a function of depth (burial history) and proximity to thermal sources. Maturation provides the chemical reactions in the pathway (see Figure 5.1) required to produce gas.
