Abstract:

Main driving force for migration of separate phase natural gas is buoyancy, and resistance is capillary force. According to previous experimental data, it is found that the buoyancy and capillary force are effected by reservoir temperature and pressure, and the boundary height of natural gas comingup so on.The boundary height of natural gas comingup is accreting along with the reservoir temperature and pressure decreasing.Based on natural gas state equation and dynamic theory of natural gas migration, natural gas velocity of flow rate equation before and after temperature and pressure decreasing is fetched, and with which interface natural gas lengths in different reservoirs are calculated and the changing law of equivalentlength natural gas in migration is analyzed, whence it is discovered that migrating velocity of natural gas along tilting up reservoir is increasing inch by inch，along with temperature and pressure continuously decreasing. If other natural gases join, the natural gas length would increase, and the migrating velocity of natural gas would increase more quickly.

Key words: oil and natural gas migration, boundary height of natural gas, buoyancy, capillary force