Key Oil Content Parameter Correction of Shale Oil Resources: A Case Study of the Paleogene Funing Formation, Subei Basin, China

Estimating shale oil resources is critical in shale oil exploration, and thepyrolysis parameterS1is a frequently used parameter to assess the oil amount in shale.However,S1loses some light and heavy hydrocarbons due to core storage conditionsand experimental technology, resulting in underestimating shale oil resources. In thispaper, a set of models were developed to correct the light and heavy hydrocarbonlosses forS1based on conventional and multistage Rock-Eval experiments onliquefrozen and room-temperature shales collected from the Funing Formation, SubeiBasin. Two types of correction models of heavy hydrocarbon loss for liquefrozen androom-temperature shales were determined by comparing the conventional andmultistage Rock-Eval experiments, respectively. The light hydrocarbon loss correctionmodel was obtained according to conventional Rock-Eval experiments on liquefrozen and room-temperature shales. Moreover, theestimation models of adsorbed, free, and movable amounts of oil were determined and validated by the oil saturation index (OSI)method. The results show that the total, adsorbed, free, and movable oil contents can be estimated well by these correction models.A case study from the Funing Formation, Subei Basin, indicates that the higher the content of total oil, the higher the amounts offree and movable oil, indicating that shale with more oil also has a more excellent mobile and developable potential. Organic matteris the main adsorbent for shale oil. Shales with TOC greater than 1.5% generally have greater free (movable) oil amounts, which maybe the optimal target for shale oil exploration and exploitation. This study provides an innovative approach to correct the keyparameters of shale oil resources, and thus, is crucial for the exploration and development of shale oil in the Funing Formation, SubeiBasin.