Lithofacies Palogeography Characteristics Of Jurassic In North East China

Northeast China is composed of several micro plates and located between the Siberia plate and the North China plate, where tectonic movement is complex. The area that development of Erlian, Hailaer, Songliao and other sedimentary basins is rich in oil and gas resources. The Jurassic is an important tectonic period of Northeast China. Under the background of regional tectonic evolution, this article study on stratigraphic division and correlation, analysis the sedimentary system and sedimentary model, restore the lithofacies paleogeographic characteristics and the evolution history of Jurassic in northeast China and then identify the source rocks and the paleogeographical conditions of source-reservoir-cap assemblages and finally forecast the favorable exploration area.The main sedimentary zone of Early Jurassic northeast region is located in the Erlian basin and Hulin basin, the Erlian basin is a continental basin characterized by the depositional system of the faulted lacustrine basin. Most of the regions are fluvial facies,and the shallow lacustrine facies are developed in some areas. Hulin basin is a set of offshore clastic rocks, from the edge to the interior are developed in shallow shelf facies, transitional facies and fluvial facies. In the Middle Jurassic, the sedimentary center migrated to the central and western regions, the Hulin basin was uplifted and eroded,and the regional subsidence of the Songliao basin underwent deposition, the main sedimentary facies are fluvial facies and shallow lacustrine facies. The sedimentary environment of the Erlian basin is characterized by the evolution of the early fluvial facies to the middle shore shallow lake facies and the late deep lake semi-deep lake facies, and a set of intermediate acid volcanic clastic sediments in Hailar basin. In the Late Jurassic, the sedimentary center migrated to the north, the Mohe basin began to develop, was widely accepted. The alluvial fan facies,fluvial facies and shallow lacustrine facies were developed from the interior to the edge; The western Hailar basin is dominated by alluvial fan facies and shallow lacustrine facies; Under the influence of transgression, the eastern Sanjiang basin and Hulin basin shallow shelf facies sedimentary system.In the Early Jurassic, basin is controlled by the tectonic direction of the orogenic belt and deep fault, central areas of the terrain is high and gradually reduced to the east and west. Erlian basin and Hulin basin were in developed sedimentation. Erlian basin is a typical rift basin, while Hulin basin were shallow shelf facies because of the transgression. In the Middle Jurassic, the effect of volcano activity, Songliao Basin and Hailar basin began to develop, under the influence of Isawa Nayin to the subduction of the plate with high speed and NNW direction, the eastern uplift in Northeast China, the sedimentary center migration to the central and western regions.Under the influence of volcanic activity, Songliao basin and Hailar basin began to develop,there is a great change in the sedimentary environment of the Erlian basin,because the control action of basement faults, on the west side of Daxinganling there developed Labudalin basin and Genhe basin. In Late Jurassic,the Mongolia Okhotsk ocean are all closed with the formation of EW - NEE Mongolia Okhotsk orogenic belt, the sedimentary center migrated to the north. Under the control of faults, the middle and small sized back-arc extensional rift basins developed, such as Dayangshulin basin?Yichun basin and Donghe basin.Under the comprehensive analysis of the types of sedimentary facies and lithofacies paleogeography in this area, we can find the Jurassic oil and gas exploration targets are Erlian basin Alatan force group, the Genhe basin and Labudalin basin in the Middle Jurassic Wanbao group, the middle-lower Jurassic Xinanling group in Hailar basin and Baicheng formation of Songliao basin. The favorable petroleum exploration areas are Ananabei sag, Aqituwula sag, Wuliyasitai sag Saihantala sag in Erlian basin. Ershierzhan, Malin, Laogou, Xiaobeigou,Xinganxiang and other places in Mohe basin. Wuerxun sag, Beier sag, Wugunuoer sag in Hailaer Basin, and Xiwuzhuer Shanghulin Yiligen area at the east side of Eergunahe in Genhe basin.