Abstract:

The number of China's medium and big gasfields is only 20.8% of the country's total mumber of gasfields,but their reserves are 83.44% of the total reserve;the number of big gasfields is 4.3% of the total number of gasfields,but their reserves are 50.35% of the total reserve.The reservoir rocks of the medium and big gasfields are predominantly sandstone and carbonate rock,their reserves are 99.65% of the total reserve.This coincides with the tendency of world's gasfields.It thus indicates that China's gas exploration should always aim at big and medium sizes of sanstone and carbonate rock gasfields.According to the distribution of structural palaeogeography,gas exploration provinces could be divided into 4 type:1.inner cratonic basins in Central China;2.composite basins in West China;3.epicotinental basins in Southeast China;4.rift basins in East China.These basins correspond to gas,oil,rich gas and gas-bearing provinces respectively.On this basis,the furture strategy is enhancing Central China gas exploration, developing West China gas explaration,paying more attention to marine exploration and improving exploration in East China.

Key words: natual gas, reservoir, structure, palaeogeoraphy, exploration orientation