Based On The Analysis Of Seismic Attributes Sensitive Petrophysical Model

The sensitivity of the seismic information for reservoir parameters (velocity, porosity,pore fluid type,acies and saturation)has always been recognized. However, with the advances in seismic exploration acquisition processing,and demanding of the detection of hydrocarbons, reservoir description, reservoir monitoring and seismic interpretation. Discover and understand the uncertain relationship between the seismic parameters and reservoir parameters is very essential.Rock physical model can help us establish a bridge between seismic parameters and reservoir parameters,which can be found some sensitive relationships between them.This paper first introduces several rock physical models with different theories. Including the most widely used Gassmann model,Kuster-Toksoz model and differential effective medium model which considered the different pore inclusion shapes,contact cemented model and constant cemented model which considered the rock particles cemented.Elaborated the principle of the method, mathematical formulas, scope, assumptions for these models, as well as the advantages and disadvantages.For striking different pore shapes in the models,two different algorithms proposed by Wu and Berryman.Aimed Dainan core samples for Gaoyou Sag in Jiangsu Basin, description the sheet identification results of these samples as well as the measurements of porosity, permeability,V-wave velocity,S-wave velocity,and density.Examined the adaptability of the Gassmann model,Kuster-Toksoz model,and constant cemented model to the fine sandstone tested datas,comparative analysis that Gassmann model has the best adaptability.This is found the most suitable rock physical model for the study area, which provided a theoretical basis for the study of the sensitivity of the relationship between seismic attributes and reservoir parameters.In this paper,according to Gaoyou Sag Dainan typical geological features, established a thin interbedded stacked sand body model,and calculated using different imaging methods,and extracted50kinds of seismic attributes from the acquired seismic profile.According to a standard that the two forward modeling method to extract seismic attributes both have good fittings with the sand body model,preferred out four kinds of representative sensitive seismic attributes.In order to analysis and find the cause of the sensitivity of these seismic attributes,used Gassmann model to change the rock physical parameters in the sand body model,and designed five geological models which have different reservoir characteristics and fluid properties. Through research the sensitivity of the relationship between the preferred seismic attributes and the changing velocity of local sand body can help us to predict the lateral distribution of the reservoir characteristics, and through research the sensitivity of the relationship between the preferred seismic attributes and the changing cumulative thickness of the sand body can help us to predict the vertical distribution of the reservoir characteristics.