Study On The Sedimentary Characteristics In Sublacustrine Fan

The Dyna Formation in the deep depression of the Gaoyou sag has a good development condition of the sand body of the lake bottom and is an important area for the exploration of subtle reservoirs in the Jiangsu oilfield.Due to the previous lack of attention to the deep recess,the predecessors’research on this is relatively weak and lacks detailed understanding.Therefore,on the basis of a large number of core observations,combined with regional geological data,well logging data,logging data and se ismic data,and various geochemical test data,the formation mechanism of the lake bottom fan during the sedimentary period of the Dainan Formation in the deep depression of Gaoyou Sag,sedimentary characteristics,sedimentary evolution and sedimentary model for detailed and in-depth research,combined with Professor Dong Guiyu’s"seesaw"theory in 2016,discussed in"beam"（source）+"ditch"（valley）+"slope"（slope）The distribution law of the sand body of the lake bottom under the grid.The paper comprehensively identifies the three subphases of the outer fan,the middle fan and the inner fan.According to the fine description of the core,it is found that three sub-concaves（Shao Bo,Fan Chuan and Liu Wushe sub-concave）develop a large number of the paleo-earthquake action and the traces of the ancient storms,accompanied by abundant quasi-symbiotic deformation structures,indicating that the tectonic activity in this area is severe and has an external trigger mechanism for forming the lake bottom fan.Analysis of sedimentary facies distribution characteristics based on single well phase and continuous well phase by point-line method.It shows that the lake bottom fan only develops in the E₂d₁²,E₂d₁¹,E₂d₂⁵ and E₂d₂⁴ periods,and the depth from the E₂d₁² to E₂d₁¹ deep recessed water body becomes larger,and the scale of the lake bottom fan sand body also expands to E₂d₂⁵ deposition.During the period,the water body became shallow,the semi-deep lake-deep lake sediment disappeared,the lake bottom fan scale became smaller,and the E₂d₂⁴ deposition period did not change much on the whole scale.Figure38;Table10;Reference 70...