Research on Gas Characteristics and Partition Prediction of Gas of Laoshishan Tunnel

Research purposes: On the basis of the survey data on oil and gas exploration in the study area,by making the investigation and analysis of the geological background in the region of Laoshishan Tunnel along with doing the characteristics observation,gas density test,other field tests and laboratory tests to the point where the gas spills,the study was done on the tunnel's gas source,migration mode,distribution characteristics and reservoir properties and the partition prediction of the gas in tunnel was made to provide the reference to the tunnel design and construction. Research conclusions:(1) The tunnel exit is located in the anticline structure zone,and it is favorable for the oil and gas migration and accumulation,so the special attention should be paid to it.(2)The tunnel passes through some oil and gas formations,and the under these formations there are also some oil and gas formations and reservoir stratum.Although some of the oil and gas formation are directly exposed to the surface and the reservoir performance is poor,but there is possible that the residual oil and gas concentrate in some places.(3)The natural gas found in the construction comes from the deep Silurian system and Cambrian system formations,moves upward the tunnel along the Longquansi Zhangniu Fault Zone and overflows.The fault zone is the main channel of the natural gas moving upward,so the corresponding measures should be taken.(4) According to the comprehensive analysis of the stratigraphic distribution,structure characteristics and the oil and gas formations,the gas grade of the Laoshishan Tunnel was confirmed.