A Study on The Evolution of Hydrodynamics, The Migration and Accumulationof Oil and Gas in The Songliao Basin

Key words: 
• hydrodynamics /
• migration and accumulation of oil and gas /
• Songliao basin

Abstract: The hydrodynamics field in the Songliao basin is obviously asymmetrical with the characteristics ofgravity- induced centripetal flow recharged by meteoric water mainly in its northern region, centrifugalflow and cross-formational flow in the basin center area, groundwater discharged by cross-formationalflow and evaporation in its southern area, and meteoric water permeating dow nwards only along thebasin rim and uplifted areas locally and unabidingly.Centrifugal flow caused by mudstone-compactedwater is the main dynamic force which induces the petroleum migration and accumulationin the Songliaobasin.Paleohydrogeologic cycles and centrifugal flow stages induced the migration by stages and step-mannular distribution of oil and gas in an independent hydrodynamic system.Multidepressions for theSongliao basin would have developped several hydrodynamic systems.Of which two major ones are lo-cated at the Sanzhao and Qijia-Gulong depressinons, and they made up a double step-annular distributionof oil and gas in the Songliao basin.Inside are multirings of oil, which are encapsulated by uncontinuousnatural gas pools.All of them are concentric with their depressions mainly due to symmetric and concen-tric centrifugal flow.