Study On The Oil Shale Geochemistry Of Permian Lucaogou Formation In The Northern Bogda Mountain

With the shortage of energy resources, oil shale emerges as an alternative energy resource for its three key virtues. Under the research of geochemistry on oil shale, the sedimentary environment can be determined, and oil shale quality can be described, and the dry distillation products can be shown, and then the oil shale pre-development background is clear. Under the guidance of geochemistry, this paper does researches on several aspects such as: sedimentary environment, source input, organic character, dry distillation products character, organic facies, and quality of oil shale in different organic facies of oil shale of Permian Lucaogou formation in the northern Bogda Mountain.The northern Bogda Mountain was continent rift lacustrine basin during the sedimentation of Permian Lucaogou formation. Trace elements and biomarkers parameters show that oil shale developed in saline lake, and in reducing and soft reducing, deep and semi-deep environment, where large quantity of nutrient elements was input by surrounding volcano activities. The main source materials of oil shale are lower hydrobionts such as algae, partially higher plants. According to the latest assessment criteria of China, the majority of the oil shale in northern Bogda Mountain belongs to medium oil yield grade, which is further better than oil shale of China. Except for Tar, TOC and S1+S2 were alao founded as effective parameters for oil yield. The types of organic wereⅠandⅡ, which were showed by several methods at the same time. The kerogen was in low mature stage, with Ro between 0.56 and 0.84, Tmax below 470℃., so the oil shale have huge hydrocarbon generation potential. Based on the kerogen type, the pyrolysate is high-wax paraffin oil, which is similar to Green River oil shale.The progress of the oil shale thermal degradation can be divided into three stages: preheating period, large amount of hydrocarbon generating period and ending period. The majority of products were generated in the second stage. Compared with natural crude oil, artificial thermal products contained series of olefins, which were generated by rapidly pyrolysis. The n-alkanes/n-olefins is a good discriminabiltity index. According to above results, the organic facies of this area can be divided into four types: high salt deep lacustrin organic facies, reducting semi-deep lacustrin organic facies-1, reducting semi-deep lacustrin organic facies-2 and soft reducting semi-deep lacustrin organic facies. Among the four facies, reducting semi-deep lacustrin organic facies-1 is the best facies, and Semi-deep lake is the best environment for the development of oil shale.