Prediction Of Tight Oil Reservoirs In Qianan Area,southern Songliao Basin

The research block of this paper is the Qianan area in the southern part of the Songliao Basin.The main target formation is the Fuyu oil formation in the Quan 4^thmember.The main sand group is the I sand group and the III sand group of the Quan 4^thmember.The target layer is seriously affected by the T₂ low-frequency strong reflection shielding.The reflection energy between the I sand group and the III sand group is weak,the river sand body and the thin interbed sand body are difficult to identify,and the reservoir prediction is difficult.This paper studies the above issues.Through the research and analysis of the seismic data in the research area,combined with logging and geological data,the structural interpretation and reservoir prediction of the research area are carried out.The fine structural interpretation mainly includes three aspects:fine interpretation of the horizon,production of more than 20 exploration wells,and synthetic seismic records of the evaluation wells.The synthetic seismic records are used to accurately calibrate the seismic reflection formation of the Quan 4^th member,and complete geological stratigraphic correlation of the main target sand group.Fault identification and interpretation,using the coherence of the Geo East seismic data interpretation software to perform the fine identification of the fault plane,and then carry out the fault interpretation work,laying the foundation for the next step of structural mapping.The fine structural mapping,and the structural mapping of three-dimensional data body of260km² in the Quan 4^th member of the research area is completed by using the full three-dimensional fine structure interpretation technique.The reservoir prediction technology mainly has the following two aspects:the attribute extraction of two favorable sand groups in the target formation,and the extraction of the root mean square amplitude,fluid activity,oil and gas detection and other attributes of the I group of the Quan 4^th member.The III group performs spectral decomposition,highlight volume attribute extraction,and analysis of seismic attribute data to achieve the purpose of reservoir prediction.The wave impedance data volume of the research area is obtained by logging constrained sparse pulse inversion,and through the lithology analysis,the reservoir parameters which can distinguish sand and mudstone are selected,and then the geostatistical inversion is carried out to predict the reservoir in the research area.Finally,a comprehensive analysis of the research results,proposed four favorable goals.