Research On Sedimentary Characteristics Of The Palaeogene In Daluomi-xingwang Area,fangzheng Fault Depression

Fangzheng fault depression is a double fault fault depression which located in themid-north part of Yi-shu graben.It is considered to be the most complex continentalrift basin in northeastern of China.because of its complex geological conditions, a lotof oil and gas resources is yet to be developed. Daluomi-Xingwang area is located inthe northeast of Fangzheng fault depression, in recent years, after high yield industrialoil and gas flow were founded for the first time, people explored in depth the thepotential of oil and gas in this area. Describing the sedimentary facies, researchingthe the exhibition of sedimentary facies and characteristics of sedimentary evolutionhave an important practical significance for the oil and gas exploration prospect.Combining with previous research results,we carry out regional geologicalresearch, stratigraphic classification and correlation, sedimentary facies recognitionand classification and the characteristics of sedimentary facies distribution by meansof core,logging and seismic data. In terms of regional geology research, we discussthe fault formation development situation and six founder tectonic evolution stages; Interms of stratigraphic division and correlation,we divide the the stratum of study areainto third sequence and system tract,and establish the sequence stratigraphicframework by analysising single well and connected wells. In terms of sedimentaryfacies signs and types,we identify fan delta facies,lake facies and sublacustrine fanfacies, and further divide the three sedimentary facies into8subfacies and16microfacies; In terms of sedimentary facies distribution characteristics，we analysisedthe typical single well facies,connected wells facies and plane facies to discuss the plane distribution features of sedimentary facies and laws of the sedimentaryevolutionOn the whole, Xin’ancun and Wuyun Formation constituted a sedimentarycycle,in early Xin’ancun and Wuyun Formation lake facies developed,forming thedark mudstone in the lower part of the study area.During the late Xin’ancun andWuyun Formation the sediment supply was sufficient,fan delta facies developed on alarge scale,and the sublacustrine fan facies developed in the late district,both of thefan delta facies and sublacustrine fan facies could contribute to the reservoir rock.Onthe whole,it formed a fan delta-shore-shallow lake-deep lake sedimentarysystem.From the member1of Baoquanling Formation to the member2ofBaoquanling Formation,the water deepening increasingly.The study area developedsmall-scale fan delta facies in the first member of Baoquanling Formation.In theperiod of member3of Baoquanling Formation,the lake water reached the maximumflooding surface,this expended the area of the lake facies and reduced the area of thefan delta facies.In the late member2of Baoquanling Formation, the lake basin startedto atrophy, and the supply of surce was abundant.In the member3of BaoquanlingFormation,Fangzheng fault depression entered the shrinking stage of itsevolution,and the water became shallow gradually.