A study on thermal evolution of organic matter in Jurassic coal-bearing source rocks of Santanghu Basin

By using the method of organic petrology on whole rock surfaces and combing with the data of organic geochemistry,this paper was carried out a detailed study on thermal evolution of organic matter in Jurassic coal-bearing source rocks of Santanghu Basin.There were both general character and special feature of thermal evolution of Jurassic coal-bearing source rocks in Santanghu Basin. The former generally demonstrates that the vitrinite reflectance(R), the fluorescence parameters(i. e. λ_max,Q,I₅₄₆) of sporinite and the molecular geochemical indexs (such as C₃₁ ho-pane 22S/(22S + 22R)) of soluble organic matter are of important significances in indicating the level of thermal evolution in Santanghu Basin. The latter is mainly reflected in several aspects,such as no obvious correlation between the indicators of thermal evolution and the present burial depth, the similar degree of thermal evolution in the same member, the differential evolution of different organic macerals and the obvious stage properties of thermal evolution of organic matter. Based on these suggestions and authors' previous results,a model of oil generation from Jurassic coal-bearing source rocks of Santanghu Basin is preliminary established.