Kerogen Solution Theory and Its Exploratory Application in Shale Gas Assessment
干酪根溶解理论及其在页岩气评价中的应用探索

This article introduces the kerogen solution theory as well as a hydrocarbon expulsion model on its basis and brings forward the conclusions as follows.As to the kerogen(TypeⅡ)of high matured(TRHI>75%),the expulsion efficiency of oil(C6-15+) exceeds 69% and the expulsion efficiency of gas(C1-5)can reach as high as 97%.The result calculated shows that the gas retained in high matured kerogen(TypeⅡ) is about 2.84mg/gTOC(not total gas content of shale).The writers explore to apply the kerogen solution theoretical model to indirectly characterize the content of adsorbed gas and come to the conclusion that gas adsorbed in shale accounts for a small proportion.While the content of free gas within pore or fracture created through diagenesis(like montmorillonite transforming to illite),kerogen degrading or structural activity is high,making a significant contribution to the production of shale gas.Therefore,much more importance should be attached to finding the "sweet spots" where micro-nanopores and nature micro-fractures develop in the activity of shale gas exploration & development.