The Fine Structure Interpretation And Reservoir Prediction Of The Triassic Baikouquan Formation In The Da 10 Well Block In The Hinterland Of The Junggar Basin

Da10 well 3D seismic survey is located in northeast of Dabasong uplift,abdomen of Junggar Basin and its west side is adjacent to Mahu depression.Mahu depression is the most favorable hydrocarbon generation sag in the Junggar Basin.The slope area,as dominant area of oil and gas migration,have rich resources of oil and gas.The Triassic Baikouquan formation(T1b)in the study area is good in physical properties and have favorable conditions for the accumulation of oil and gas.This paper is based on the cooperation project of PetroChina Xinjiang field branch's exploration department,and the research object is Triassic Baikouquan formation in Da10 3D survey work area.By using existing logging data and the newly acquired Da10 well 3D seismic data,combining with the structure guided filtering technology,curvature cube,coherence cube technology and variable speed mapping technology,fine structural interpretation of the target formation in the study area has been made.Sedimentary facies were analyzed by combining single well phase,seismic phase division and attribute analysis.By means of poststack impedance inversion in combination with prestack elastic impedance inversion,this paper predicted traps and depicted sand bodies.This paper also analyzed the trap oil and gas and optimized the favorable exploration targets by using multi-wavelet reconstruction technology and combining with structural interpretation and reservoir prediction results.Through structural interpretation,the structural feature of the study area has been clarified.T1b formation,controlled by sedimentary background,emerged with gradually thickening characteristics form northeast to southwest of the study area,with the thickness of T1b variation ranging from 140m to 320m.The study area developed three groups of faults.The first group,controlling uplift,forming in Hercynian periods and keeping active in Indosinian epoch,are reverse faults,and their strike direction is nearly the North East.The second group are strike-slip faults near the East and West,and they were formed in Indosinian epoch,and part of those faults were reactivated again during Himalayan Epoch.The third group of faults,forming in the period of Yanshan,are tensional fracture,with their distribution in the form of wild goose row.Sedimentary facies analysis shows:T1b formation is fan delta deposits superposed by multistage transgressive system domain,developing fan delta plain sub-face,fan delta front sub-face and shore-shallow lacustrine sub-face.Fan delta front subfacies is a favorable reservoir development zone,fan delta plain sub-face and shore-shallow lacustrine sub-face 's physical properties are poor,which provides the lateral sealing condition for the reservoir sand bodys.The reservoir prediction found 16 fault lithologic traps in T1b,and its total area is 255.2km2.By analyzing the main controlling factors of accumulation,such as reservoir physical property,reservoir caprock combination and transportation and accumulation conditions,5 fault block traps and 4 fault lithologic traps are optimized.Aiming at the optimized targets,it is suggested to provide 8 Exploration well position,among which Da13 well has achived breakthrough after oil test.