Mudstone compaction curves are the most basic data in studying migration.especially the primary migration

of oil and gas. Through the study of somemain oil- and gas-bearing basins in our country

it has been found that most of the compaction curves can be divided into two sections: normal and abnormal. The abnormal section usually appears at the depth of more than 2000 m;its vertical and horizontal distributions are mainly controlled by sedimemary facies as well as lithology and their association. With the synthetical study of the compaction curves

the compaction history of source rocks can be recovered

furthermore

the primary hydrocarbon-escape depth and the development of effective soure rocks can be inferred. The pressure profiles

which are converted from the compaction curves

are the foundation to distinguish hydrodynamic system and to analyse the possible direction

degree and distance of oil and gas migration in that area.