Tanan sag is one of the important oil-rich sags in Haita Basin,and most of the dis-covered oil reservoirs are controlled by faults.In order to explore the controlling effect of fault elements on oil reservoirs in Tanan sag,a fine dissection was conducted on 191 discovered fault-controlled reservoirs based on the data of seismic,drilling and oil testing.The fault char-acteristics were analyzed,the key elements of fault-controlled reservoirs were defined,and the fault-controlled reservoirs model was established.The results show that the effectiveness of fault traps in Tanan sag is affected by fault elements to varying degrees,and its essence is to affect the fault sealing.Among them,occurrence,activity rate and type are the key elements that affect fault sealing and control reservoir formation.The fault characteristics favorable for reservoir formation in Tanan sag are as follows:strike NE,dip angle 55.-85°,fault distance 10-150 m,activity rate＜20 m/Ma,SGR＞0.35,Rm＞0.30,and combination styles of ob-lique and horst-graben,which are dominated by the combination of secondary and tertiary faults.There are three fault-controlled reservoir modes in Tanan sag:the first is that the pri-mary reservoir mode of sub-source lateral transport fault blocking,the second is that the pri-mary reservoir mode of inner-source vertical transport fault blocking,and these two modes are controlled by early extensional faults and early extension and middle tension-torsion faults.The third is that the secondary reservoir mode of above-source vertical transport fault blocking,which is controlled by long-term inherited faults.This research provides theoretical guidance for fine evaluation and exploration deployment of fault-related traps in Tanan sag.
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