Formation And Evolution Of The Aogula Fault In The Songliao Basin And Its Significance In Hydrocarbon Accumulation

The Aogula fault is a large fault adjacent to the western slope area of the Songliao Basin.It plays an important role in the lateral migration and accumulation of the oil from the QingI source rocks of the Qijia-Gulong sag to the western slope area.In this paper,based on the 3D seismic data,though to study of the formation and evolution characteristics of the Aogula fault,the spatial coupling relationship between the distribution of the Aogula fault and the sand body in the S-P-G oil reservoir,the spatial coupling relationship among the oil and gas lateral migration path,the fault transfer zone and the fault lateral open area,the spatial coupling relationship between the open area of matching between fault and cap-rock and the fault plane ridge,the relative size of the fractured shale content and its distribution characteristics,the spatial coupling relationship among the fracture associated trap and the fault transfer zone and the strike,a comprehensive and detailed study has been carried out on the control effects of the Aogula fault on the distribution of sand bodies,lateral migration of oil and gas,vertical and lateral adjustment migration of oil and gas,and the development and distribution of traps separately.The main research results are as follows:1.The Aogula fault is a northeast-trending fault,which is formed by the segmentation growth and connection of seven branch faults from the deposition period of the Nen 3rd segment.2.The Aogula fault has obvious control effects on the sand body distribution of the S-P-G oil layer,especially the P oil layer and the Saertu oil layer.The distribute channel sand body extending from the northwest direction passes through the transfer zone belt through the Aogula fault.When entering the lake basin,the sand body at the transfer zone is more developed.3.The hydrocarbons from the QingI formation in the sag area migrate to the western slope area laterrally,during the activity period of fault,the hydrocarbons migrate laterally to the west through the northern transfer zone of the Aogula fault mainly,and then accumulate in the Taikang uplift zone,and the oil cannot move westward through the south and central of the Aogula fault;when fault activity tends to rest,the Aogula fault is laterally closed,and the oil and gas cannot move westward through the Aogula fault,which makes the oil and gas cannot accumulation on the west side of the central and southern parts of the Aogula fault.4.During the active period of the fault,the oil and gas can be vertically adjusted and transported along the ridge of the Aogula fault in the S-P-G oil reservoir.After the cessation of the fault,only the oil and gas can be vertically adjusted and transported in the north part.Lateral adjustment and migration can occur in the northern part of the Aogula fault during the fault activity period,which makes the oil and gas near the northern part of the Aogula fault more enriched.5.The Aogula fault is not only associated with structural traps near the S-P-G oil layer,especially the upper plate is conducive to oil and gas accumulation,and it also forms a sand-fault configuration trap with the northeastward distribution sand body,which is more conducive to oil and gas gathered near the trap.The above research results are of great significance for the correct understanding of the oil and gas distribution of the S-P-G oil reservoir and the guidance of oil and gas exploration in the western slope of the Songliao Basin.