Study On Seismic Prediction Of Putaohua Oil Reservoir In X Area Of Northern Yongle Syncline

With Daqing Oilfield gradually entering the middle and late development stage,the output of the oilfield has declined year by year.In order to ensure stable production and increase production of the oilfield,it is necessary to carry out fine geological research on syncline blocks with unfavorable overall reservoir forming conditions.Block X is located in the north of Yongle Syncline,which is in a syncline shape as a whole,which is somewhat different from the main shape of Daqing Placanticline.This time,combined with drilling,logging and seismic data,we conducted reservoir seismic prediction research on the study area to clarify the distribution of reservoirs and provide reliable data support for reservoir increase and production increase in this area.Guided by the theories of reservoir geology,geophysics and reservoir description,this paper demarcates the PI oil formation of Putaohua oil layer in the study area,defines the reflection characteristics of the top and bottom interfaces of the target interval,and realizes the calibration and interpretation of the internal small layer interfaces of the oil layer according to the drilling layering.On this basis,the seismic attribute analysis of Putaohua oil reservoir was carried out,and the amplitude attribute and sweet spot attribute were selected and analyzed to complete the qualitative prediction of the plane shape of each small layer of Putaohua oil reservoir.Through the detailed analysis of drilling data,the seismic inversion reservoir prediction research of Putaohua oil layer is carried out.On the basis of curve preprocessing,sensitivity analysis and feasibility analysis of inversion,geostatistical inversion of the target interval has been completed,and the distribution characteristics of sandstone thickness of each small layer have been clarified.The sandstone thickness of each small layer of PI oil formation is distributed in the 0-6.5m interval,of which the sandstone thickness of PI03,PI05 and PI07 small layers is large,which are the main small layers.The sandstone thickness of each small layer as a whole is characterized by thick in the surrounding and thin in the middle.According to the regional sedimentary characteristics and the identification of single well microfacies,five types of sedimentary microfacies of Putaohua oil layer,namely,underwater distributary main channel,underwater distributary shallow channel,underwater interdistributary shoal,lenticular sand and mud powder,are determined,and combined with seismic attributes and inversion sand body prediction results,the study of sedimentary microfacies characteristics of small layers is completed.A large number of river channels are developed in PI02 and PI04-PI09 small layers,and the shape of the river channels is mostly north-south banding,mainly located in the west,northwest and southeast of the study area.On the basis of the above research results,the control of reservoirs and sedimentation on oil and gas is studied.In combination with the distribution characteristics of oil and water in the block and the regional reservoir forming conditions,the study area is divided into three types of favorable potential tapping areas: the favorable paleostructure area is located in the east of the study area,close to the high point of the paleostructure,where oil and gas converge during the reservoir forming period.The favorable area for reservoir formation in the lower part is located in the south of the study area,and oil and gas are mostly distributed in the lower part due to the blocking of local mudstone barriers.The favorable area of micro structure is located in the north of the study area,and oil and gas are mainly concentrated in the upper part of the reservoir.