Abstract:

Simulation experimental result shows that the rate of natural gas migration decreases with the increase of compaction extent in carbonate or clay rocks. But in quartz sandstone, compaction extent has less effect on migration rate, high rate of migration which is 700 times as it in clay rocks was obtained even if in burial depth of 5000m (equal to 1300kg/cm²). The experimental result also indicates that, during migration of natural gas in carbonate or clay rocks, mineral matrices have different retaining abilities for gaseous hydrocarbons with different molecular weight. That is, C₁ and C₂ have the highest migration rate, and the ratio of C₁/ΣC₁-C₅ is not only related to the type of organic matter, but also to the migration distance of natural gas. Long distance migration may make it into dry gas.