Cap Rock Characteristics of Medium and Large Gas Fields in China
中国大中型气田盖层特征

Based on the statistics of cap rock parameters of medium\| and large\|size gas fields in China, the qualitative and quantitative evaluations of the cap rock sealing capacity have been studied. The cap rock lithology of most medium and large gas fields is mudstone and the thickness of the cap rocks ranges from 50m to 350m. The displacement pressure of the cap rocks is high and ranges from 10MPa to 30MPa. The diffusion coefficient of the medium and large gas fields is generally less than 10-6cm2/s. The cap rock condition of the gas field with lithological traps is weaker than that with structural traps in the aspect of thickness and displacement pressure.