| The geological history of oil and gas is its migration history.Fluid seepage always moves along the path with the best permeability and the least resistance.The dominant channel of oil and gas migration depends on the coupling relationship between the ancient fluid potential and the transport system.As a “core bond” of the source rock and reservoir,the transport system is the key control factor for oil and gas accumulation.If the transport channel of the study area is well understood,and the dominant channel of oil and gas migration is confirmed,we can accordingly deploy exploration,make an accurate prediction of favorable target zones,and then reduce exploration risks.Based on the previous studies and taking Fuyu reservoir in Xingbei area,Songliao Basin as the study target,through the field exploration data from field observations,three-dimensional earthquakes,surveying,logging,oil exploration and other biomarkers,the oil and gas transportation characteristics of faults are systematically studied,and the configuration relationship between faults and sand body is analyzed.Meanwhile,the oil migration path and its control function of reservoir-forming are further described from the perspective of both plane and profile,and the favorable oil and gas accumulation targets are predicted.The main study results are as bellow:1.The migration channel of Fuyu oil reservoir in Xingbei area is composed of connected sand body and transport faults.In addition to the non-connected sand body of Fuyu in the central and western regions,the sand body in other areas is all connected,and in the northern and southern parts a set of connected sand body distribution area is formed,a reverse fault system of middle and late torsional stage(?-?)is the most important adjusting fracture and channel for oil and gas transportation.Transport faults is mainly distributed in the middle of Xingbei area and relatively less on the east and west edge.2.There are 3 sets and 6 oil migration paths developed in Fuyu reservoir of Xingbei area,among which,in FI layer a set of 2 migration paths in the same layer is developed,while in the FII layer 2 sets of 4 cross-layer.The 2 oil migration paths in FI and FII are basically the same as for the horizontally distributed locations,one is northwest to the southeast distributed in the northwest area,and the other is from the southeast to the northeast,east and southeast in the middle and west area.3.The control function of oil migration path on oil accumulation and distribution of Fuyu reservoir in Xingbei area is mainly manifested in three aspects:(1)Oil and gas distribution is controlled by oil migration path and its distribution.At present,oil found in Fuyu reservoir is all distributed in or near the oil migration path;(2)Oil and gas enrichment degree is controlled by oil migration path development degree.The oil and gas migration path in the central south part of the west area is divided into three branches to the northeast,east and southeast,and the oil and gas formed under its control is relatively more while there is less oil and gas in the northwest area because of only one oil and gas migration path existing.(3)The oil and gas enrichment locations are controlled by the vertical distribution of different types of oil and gas migration paths,and the FI layer has migration paths in both the same and cross layers,thus there is more oil and gas accumulated.While the FII layer only has the oil and gas migration paths in the same layers,there is less oil and gas gathered.4.A prediction of 4 favorable oil accumulation targets of Fuyu reservoir in Xingbei area has been made,and they are near the X11 respectively in northwest slope area and near the X70?XF71-7?XF71-2 respectively in southwest slope area. |
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