THE INFLUENCE OF ADJUSTMENT AND MODIFICATION ON HYDROCARBON ACCUMULATION IN TAZHONG AREA

In the complicated superimposed basin in western China,the adjustment and modification after the formation of oil and gas reservoirs are very common,through the analysis of the adjustment and modification happening in central Tarim Basin,it is recognized that the area underwent 3 to 4 times adjustment and modification,they were in Ordovician and Silurian,which was destructive,Indo-Yanshan period and Himalaya period,which were constructive.In central Tarim area,the forms of the adjustment and modification are local activity of faults and local migration of traps.There are following three aspects of the influence of adjustment and modification on the oil and gas reservoirs in central Tarim,firstly,the co-existence of multiple phase-behavior oil and gas,secondly,re-allocation of hydrocarbon resource and thirdly,the formation of the present distribution of oil and gas.Most of the discovered reservoirs in Central Tarim are the secondary ones adjusted from underlaid formations,in No.10 belt and slope break on No.1 belt in central Tarim,the underlaid Ordovician and Cambrian are of bright explorative potential.