Study On The Sedimentary Facies Of The Third Member Of Shahejie Formation In Shendanpu Area Of Liaohe Depression And Optimization Of Its Favorable Targets

The Shendanpu area is located in the northern part of the eastern sag of Liaohe depression,the glutenite body in the study area is relatively developed and has good reservoir forming conditions.Previous studies lack of systematic and detailed reservoir characterization of the target layer in this block,this brings some difficulties to further exploration and development of oil field,so it is very important to summarize the distribution law of sand body and conduct a more detailed and comprehensive sedimentary facies study of the target layer.Based on the theory of sequence stratigraphy,sedimentary petrology,seismic data comprehensive interpretation and so on,this paper conducts a comprehensive analysis of sedimentary facies of the sha3 section in Shendanpu area by combining the core data,logging data,logging data and seismic data.Firstly,sediment source analysis and sedimentary facies type analysis were carried out in the target layer of the study area.Then,the distribution law and the thickness of sand body were obtained by using seismic attributes and inversion techniques.Finally,the distribution of sedimentary facies was c haracterized by combining with reservoir inversion results,and the distribution characteristics of sedimentary facies and the change law of sedimentary system were analyzed.Achievements and understandings obtained include: Based on the theory of sedimentary petrology,combined with the analysis of sedimentary facies types by well logging data,logging data and core photographs,it is concluded that the three sedimentary facies types,namely fan delta facies,braided river delta facies and lake facies,are mainly developed in the study area.The seismic reservoir prediction technique is used to predict the sand body of the target bed.It is revealed that the main provenance in the study area is northwest and southeast,and the secondary provenance is developed in the northern part.The seismic waveform indication inversion technique is used to predict the reservoir of the target bed to get the sand body thickness.The thickness of sandstone in each sand formation of the upper submember of sha3 is over 100 meters,the maximum thickness of sandstone is 452 meters,and the sand thickness of the middle section of sha3 is mainly distributed between 100 and 400 meters.According to combine sedimentary facies analysis with reservoir prediction results,the plane dis tribution characteristics of sedimentary facies and the change law of sedimentary system are defined.From the bottom up,the sha3 section evolved from near-source sediment to far-source sediment,and from the semi-deep lacustrine facies to the shallow lac ustrine facies.On the sedimentary model,the evolution from the early steep slope fan delta facies and the semi-deep lake facies in the depression area to the fan delta facies in the east and the braided delta facies in the west.Based on the study of sed imentary facies,combined with the analysis of oil and gas distribution control factors,trap development and favorable reservoir,three favorable traps were selected and three favorable drilling targets were predicted in the optimized favorable traps.Favorable target 1 is located in Shendanpu castle pressure-torsional break convex zone,Favorable target 2 is located in the middle lift belt,Favorable target 3 is located in Tongxi trough belt.