More Accurate Quantification of Free and Adsorbed Gas in Shale Reservoirs

摘要

Determining the potential of shale-gas reservoirs involves an exhaustive process of calculating the volume of total gas, or original gas in place (OGIP). The calculation of total gas relies on calibrating wireline logs to core data, which are considered to be an empirical validation or 'ground truth'. However, inconsistency in sample preparation and analytical techniques within, and between laboratories creates significant uncertainty in calculating the five- and adsorbed-gas components, which constitute total gas. Here, we present an analytical program performed on samples of core to elucidate the causes of uncertainty in calculation of total gas. The findings of this program are used to propose improved methods of calculating total gas from core.