Study On Sequence Filling Characteristics And Reservoir Prediction Of Mesozoic Group In East Of Yu Qi Area

Yuqidong area is an important area of Clastic Reservoir in Tahe oilfield to realize the north expansion of oil and gas discovery.The Mesozoic reservoir is mainly controlled by sedimentary facies zones,which is characterized by closing to the source,lateral changes rapidly,strong heterogeneity and so on.The key exploration layers of this area are Cretaceous and Triassic,and there are good oil and gas shows in Yageliemu Formation of Cretaceous as well as Upper-oil Formation of Triassic.However,the study area with few drilling wells and a complex rock-electro relation,and seismic resolution is low,which restrict the accuracy and reliability of reservoir prediction.On the basis of the data of regional geology,drilling and logging,coring and so on,this paper synthesizes the theories and methods of petroleum geology,sedimentary,reservoir geology and geophysics,and adopts high resolution sequence stratigraphy in each layer of Mesozoic to isochronous stratigraphic division and correlation.On this basis,the interior of sequence is given priority to with the drilling data,and according to the core-logging lithologic assemblage characteristics,the shape of logging curve as well as the direction of antiquities source,this paper establishes macroscopic distribution characteristics of sedimentary system and corresponding sedimentary model,which guides the reservoir prediction and meticulous depiction of sand.In the meantime,integrating the multi-attribute analysis,well constrained pseudo-acoustic inversion and multi-attribute seismic facies analysis in isochronous frameworks,reservoir prediction and trap identification are carried out.Here are the 4 results of this paper according to the methods above.(1)This paper has identified the divisions and types of sequence boundary,and calibrated the property as well as isochronous contrastive significance,by the researches on single-well profile in the study area studying on sedimentary system,sequence boundary and physical properties of reservoir etc.Thus the comparison program of drilling profile sedimentary facies,sequence-logging facies reponse patterns,and Triassic-Cretaceous stratigraphic division in the Mesozoic are established.(2)We obtain the distribution of sedimentary system and reservoir physical properties in the profile and plane through the mutual calibration of cross-well seismic profiles and mud logging data,as well as techniques of seismic inversion and attribute extraction,and the sequence boundary is determined,the well-seismic bridge type comparison of the sequence boundary is carried out.In this way,the Triassic-Cretaceous in the eastern part of Yuqidong area is divided into 5second-order sequences(SSQ1-SSQ5)and 10 third-order sequences(TSQ1-KSQ5).(3)Based on the analysis of drilling data and single well sedimentary facies,the well logging facies play a role of a bridge to conduct comprehensive well-seismic analysis.And according to the interpretation of seismic facies,multi-attribute seismic analysis techniques are adopted in isochronous framework to distinguish different depositional system tract.In the Mesozoic area of Yuqidong,the braided river delta and lake sediments are mainly developed,while in the short period,it develops meandering river delta sediments(the lower part of the Shushanhe formation).Combined with paleogeomorphology and paleoclimatic analysis,it is found that the Mesozoic depositional model in the study area is mainly alluvial fan?river(alluvial plain)? braided river delta?lake model.(4)The well-controlled resolution technology which is combined with the hybrid phase deconvolution and spectral simulation techniques is used to improve the resolution of the 3D seismic data in the study area,and the best identification frequency range of the reservoir sand body is determined by the well spectrum simulation.On the foundation of the sensitivity parameter optimization,combined with the physical parameters of lithology change of logging data,multi-attribute seismic facies analysis to extract a variety of seismic attributes.Along with the well constrained stimulated AC inversion and seismic facies analysis,the resolution of sand body prediction is improved.What's more,the reservoir type and the distribution law of the reservoir space are clarified,which benefits the further comprehensive prediction of the lithologic trap development area.