On The Thermal Evolution And Kinetics Of Hydrocarbon Generation Of Late Paleozoic Coal Measure Source Rocks In Huimin Depression

The study has been aimed at the thermal evolution and kinetics of hydrocarbon generation of late Paleozoic coal measure source rocks in Huimin depression, Shengli oilfield. Basic geochemical analysis of samples, thermal simulation experiment and data calculation were carried on based on a great deal of literature reading and experimental design. The results have been applied to local geological condition through a professional Kinetics software. The main conclusions are as follows:1.The important kinetics parameters of simulated sample:The activate energy distribution of the kerogen for the hydrocarbon generation of C1 and C2-C5 are 57~74Kcal · mol-1 and 46~49Kcal· mol-1,respectively.2.Some valuable information has been obtained from a systemic investigation of carbon isotopic distribution of individual compounds from C1-C5, such as (1) gas carbon isotopic values have the characteristics of δ 13C1< δ 13C2< δ 13C3 with the pyrogenation temperature increasing; (2) Heating rate in the experiments have an obvious effect on carbon isotopic values. The carbon isotopic values of the products at faster heating rate show lighter than that at slower heating rate; (3) CH4 carbon isotopic values have the characteristics "heavy-slight-heavy" from low temperature to high temperature; (4) CO2 is the main component in the none-hydrocarbon gas, it'scarbon isotopic value has a trend from slight to heavy, and then to slight from low temperature to high temperature.3.The hydrocarbon-generating history of source rocks from the Huimin Depression has been simulated by the Kinetics software, with the combination of the burial and geothermal history. The results have shown that the accumulated products of CH4 are not high in Baigul and Pancanl well. The hydrocarbon-generation stopped at late Triassic and then re-generated hydrocarbons after the ground temperature grads increased. The ground temperature reached or exceeded the first hydrocarbon generation temperature in the Cretaceous. The two place show a gas-generating peak ,occurring at the geological temperature of 134℃ and 123 ℃.4.The favorable exploration direction of coal-formed gas is pointed out, coal-formed gas resource concentrate in eastern part of Jiyang Depression and Quti Uplift.This research has gotten a deep going to petroleum generation patterns of the source rocks from the Huimin Depression, and is also valuable to petroleum resource evaluation and exploration strategy.