Seismic Interpretation And Reservoir Prediction Of Upper Section Of Lower Zuunbayan In Toson Uul Oilfield

Tanan depression is one of the most hydrocarbon rich areas in the tamuchak basin of Mongolia.In the past decade,with the great breakthrough in oil exploration,Tanan depression has attracted wide attention.In the literature on Tanan depression,reservoir quality and the overall nature of the petroleum system are extensively covered.However,due to the multiple sources and multiple periods of tectonic movement,the understanding of the structure and reservoir in this area is still insufficient.With the increasing difficulty of development and the continuous progress of exploration technology,it is urgent to implement structural and reservoir characteristics.This study focuses on the structural interpretation and reservoir prediction of upper section of lower zuunbayan of block 19,Tanan sag,and further explores its structural characteristics and reservoir distribution,so as to guide the exploration and production practice in this area.The study is based on a combination of existing logging,logging,and seismic data.Based on the theory of sequence stratigraphy,the establishment of stratigraphic framework in the whole area has been completed.Based on the stratigraphic calibration results,the stratigraphic fault interpretation was carried out,and the structural characteristics of upper section of lower zuunbayan of Toson Uul oilfield were studied.Through sensitivity analysis,appropriate reservoir prediction methods are explored for reservoir prediction research.Based on the research results of structure and reservoir,the sedimentary and reservoir formation were studied,and the conditions and rules of reservoir formation were analyzed.Finally,the favorable zones were divided.The structural study shows that the present geological structure of tanan sag has the characteristics of east-west zone and north-south zone,which can be further refined into "three depressions,two depressions,one slope and one fault step",and the structural characteristics of interphase arrangement of depressions and depressions.The target stratum of this study is upper section of lower zuunbayan(symbolized as N2),which is characterized by structural inheritance and development.The plane is high in the north and low in the south,and low in the middle in the east and west.There are five types of faults in the study area,among which the syngenetic fault from Tongbomiao to Yimin formation and the epigenetic fault from Nantun formation to Yimin formation are the oil-source faults in the area.The oil-source faults in the two groups have different sizes,strike and control effects on the sand body and reservoir formation in the study area.Through attribute analysis and attribute optimization,the root mean square amplitude attribute is optimized to predict the reservoir qualitatively.Based on the analysis of sensitive logging parameters,the resistivity curves sensitive to sandstone are optimized,and the quantitative characterization of the reservoir is achieved by means of structural modeling constraint inversion,aiming at the specific problems of complex structure,development of multiple faults,fast reservoir phase transition and low degree of well control.The predicted results show that the distribution of the sandstone in the south second member is uneven,and the N2I1-N2I3 and N2II1 and N2II2 sandstones in the I oil formation and II oil formation are relatively well developed.The long axis of the sand body is mostly NW or NNW direction,and most of them are flaky.In composite structure,fracture,and based on the research of sedimentary microfacies,reservoir accumulation main controlling factors for clues,complex geological conditions,structure,traps,oil and water distribution and log interpretation results,determine the advantageous area four categories: accumulation conditions similar potential area,reserves outside enlarge potential area,favorable structure,reservoir conditions,potential area,reserves area high-yielding well exploration area.