Abstract:

Through the analysis on hydrocarbon gas components at different depths in headspace gases from the cores in DK8-19, DK10-16, DK10-17, DK11-14, DK12-13, DK13-11 in Sanlutian area of Muli, the distribution relationship of the sections with anomalistic gas component content, gas hydrate output layers, oil and gas output layers, faults or fracture zones output layers was discussed. The results show that the anomalistic gas component content sections can be compared with those of gas hydrate and its major anomaly output layers, and oil and gas output layers; the abnormal section can be used as an indication of gas hydrate and its major anomalies and oil and gas. The relationship between variation of hydrocarbon gas content in headspace gases and the location of faults or fracture zones shows that different levels of fault system from the deep can provide a channel for deep hydrocarbon gas migration or existing space for the formation of gas hydrate.The results show that the gas component of headspace gas has important significance for gas hydrate and its major anomalies, the oil and gas and the migration of hydrocarbon.

Key words: Muli,Qinghai, Sanlutian, permafrost, gas hydrate, headspace gas composition, indicative significance