The Tectonic Movement Intensity of Sanzhao Sag and the Influence on Oil Migration

摘要

Sanzhao sag is one of the main hydrocarbon generation unit in the Songliao basin, and a large number of oil and gas has been found. The distribution of oil and gas in Sanzhao sag and Daqing placantieline are obviously different, and the main reason maybe the difference of tectonic intensity. Sanzhao sag has experienced multiple tectonic movements from the formation of basin such as extrusion, stretching or subsidence, uplift. Tectonic movements change the attitude of stratum and also the time, direction and magnitude of oil and gas migration. By quantitative description of tectonic intensity in strata section, the period of oil migration is considered to begin after Nanjing group deposited. The numerical simulation results combined the quantitative description show that the gentle dip angel and weak fault activity in Sanzhao sag makes low driving force of second migration. Oil and gas migration distance is short, the direction is discrete, oil is full of sag but the trap fullness is low.