Types And Sedimentary Model Of Gravity Flow Channel In The Miocene Ledong 10 Area,Yinggehai Basin

Yinggehai Basin is a Cenozoic transition extensional petroliferous basin with high temperature and high pressure.There are many huge strike-slip faults inside.Ledong 10 area is located in the downthrown side of fault No.1.Under the main controlling factors,various types of gravity flow deposits developed in the Miocene in the eastern part of the basin.The eastern part of Yinggehai Basin develops different types of shallow marine gravity flow channels during Miocene,and different types of gravity flow channels have different sedimentary characteristics and architecture in their sandstone reservoirs.Thus,it is of great oil-gas significance for us to study the filling characteristics of different gravity flow channels types.Based on the 3D seismic,drilling and core sample testing data,the gravity flow channels are identified by the 3D closed interpretation of wellseismic calibration.According to the relationship between channel and dip direction,the gravity flow channels in this area are divided into downstream channels and axial channels.Among them,the scale(width and depth)and the sinuosity of the downstream channels gradually increase toward the basin,and their distal ends are straighter than the proximal ends,while the axial channels,overall,are characterized by small sinuosity and straight shapes,with the channels length varies greatly,from a minimum of only about 20 km to a maximum of 190 km.In addition to morphological characteristics,there are also some differences in the formation processes and main controlling factors between the two types of gravity flow channels.The downstream channels develop in the low-lying and sourceconcentration areas under the background of sea level decline,while the formation of axial channels are mainly controlled by the strike-slip-extension faults under the global sea level decline background.The northern far-sources provenance and the north-eastern near-sources provenance which provided plentiful sources are the basic condition for the group of Huangliu Group in multiple periods and large scales,The bending slope-break and fault slope-break formed by tectonic activities control the development of LST fans and axial channels,and provide necessary landform conditions for the development of large gravity flow.The regression caused by large-scale sea-level drop events in the early stage of Huangliu group has a linkage effect on the development of gravity flow.The migration of subsidence center provides necessary accommodation space for the group of large-scale gravity flow.