Seismic Reservoir Sand Body Prediction Of Southwest Slope In Yellow River Sag

In recent years,a number of large reserves of oil and gas reservoir in the Huanghekou Sag of Bohai Bay Basin are identified,among which exploration of concealed hydrocarbon has wide foreground.In this paper,the study focuses on SQs2,SQs1 and SQd3 in BZ31-32 and BZ33 work area as research objects located at the Huanghekou sag southwest slope to analyze correspondence between the lithological combinations and the seismic attributes according to the seismic sedimentology principle on the basis of the research of high-frequency sequences division and types of sedimentary facies on Group Shahejie and Group Dongying.Through using 90° phase conversion technology and sand geophysical model set up by forward modeling,finally the optimal seismic attributes and flat layout of tuning energy are selected for sand distribution prediction and seismic-deposition micro-phase combination analysis to provide the foundation for sands prediction of reservoir.Paleogene sequence stratigraphic framework is built combining with data of seismic,drilling,paleontology,petrology characteristics and it is divided into 14 system domains totally which include three second-order sequences and eight third-order sequences.Comprehensivesedimentary face analysis is carried out indetail combining drilling,rock core and seismic data,and the types of sedimentary faceshows braided river deltas and lacustrine face mainly.SQs2 and HSTd3,the principal sedimentary face types are braided river delta and lacustrine face.Moreover,the main depositional system of SQs1 is lacustrine face,and small sheet of braided river delta developments in north and southwest.Seismic properties are obtained and optimized,and lithological association andlithology and properties comparison results are analyzed based on high-resolution sequence stratigraphic division resultswith 90° phase conversion technology.In order to further illustrate the correspondence between lithology and seismic attributes,sand distributed geological-geophysical model is established,then correspondence relationship between properties sand are confirmed viatwo-dimensional forward modeling.Spectral tuning energy characteristics is used to complete sand distribution predict of key parasequence formation reservoir,SQs2,SQs1 and SQd3,as well as seismic-deposition micro-phase distribution analysis.Among which,in SQs2 pss1 and pss3,distributarychannel-river mouth bar microfacies combination sand body occupies the first and distal bar-sandy beachesmicrofacies combination sand body comes second.Moreover,in SQs1,SQd3 pss7 and pss9,distal barsandy beachesmicrofacies combination sand body increase gradually exceeded distributarychannel-river mouth bar microfacies combination sand body on the horizontal distribution area and becomes the main sand body type.However,sand area of river mouth bar-distal barcombination has always been smaller in the study area.