中国天然气储层的岩石、古地理类型与勘探方向

据统计,我国大、中型气田数量只占20.8%,储量却占83.44%,特别是大型气田只占总数的4.3%,储量却占50.35%.大、中型气田又以砂岩气田和碳酸盐岩气田占绝对优势,总储量占99.65%,与世界趋势一致,这就决定了我国天然气的勘查始终应以大、中型砂岩气田与碳酸盐岩气田为追寻目标。储层的构造古地理分布对勘探具指导意义,可分为四区:中部克拉通盆地区;西部复合盆地区;东南陆缘断坳盆地区;东部裂谷盆地区。并分别对应于气区、含油气区、富气油区、含气油区。据此,今后的勘探战略应是加强中部、发展西部,重视海域、加深东部。

EXPLORATION ORIENTATION ANE ROCK,PALAEOGEOGRAPHIC TYPES OF CHINA'S GAS RESERVOIRS

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.