Hydrocarbon Generation Pattern Of Neogene Salinized Lacustrine Source Rocks In Yiliping Area,Qaidam Basin

Research confirmed that inorganic salts affect the hydrocarbon generation process of source rock,but the influence mechanism of chloride salts on hydrocarbon generation process needs further study.we use the open system hydrocarbon generation experiments and the closed system hydrocarbon generation experiments to study the marine shale?type ?₁ organic matter?,the mudstone of salinized lacustrine facies?type ?₂ organic matter?in the western Qaidam Basin and the mudstone of salinized lacustrine facies?type ? organic matter?in the Qaidam Basin.The effects of salt salinity on different organic matter abundance and different organic matter types and the kinetic parameters are compared and analyzed.The molecular simulation of the electron inductive effect is used to explore the influence mechanism of chloride salt on hydrocarbon generation process.During the closed system hydrocarbon generation experiments,the chloride salts promoted hydrocarbon generation in the stage of low maturity to medium maturity,which made hydrocarbon generation ahead of time and promoted the formation of oil and gas.In the high maturity stage,the chloride salt promoted the cracking of oil.The activation energy of oil and gas generation was reduced by chloride salts.In this paper,we use the electron inductive effect theory to explain the catalytic effect of chloride salt.Due to chlorine ion attraction electron,the dissociation energy of the C-C and C-H bonds is reduced,and the more the amount of chlorine ion,the lower the dissociation energy.According to the conclusion of the hydrocarbon generation experiments and the regularity of the dissociation energy with the salt salinity,combined with the hydrocarbon generation charts of different organic matter types have been summarized by predecessors,we have obtained the hydrocarbon productivity charts of the salinized lacustrine facies source rocks,It is considered that the hydrocarbon productivity increases under salinity environment.The existence of the limit of salinity makes the hydrocarbon generation reach to maximum value.they can be used to calculate the hydrocarbon productivity of salinized lacustrine facies source rocks under different degrees of evolution,and can contribute to the evaluation of oil and gas of salinized lacustrine facies source rocks.