Seismic Prediction Of Fluvial Sandstone Distribution Of The Lower Guantao Formation In Zhuanghai Area,Jiyang Depression

Fluvial sandstone is a common type of continental reservoir and also an important hydrocarbon reservoir.Due to the thin sand-shale interbed,the thin single sandstone and lateral alternation of sandstone in the fluvial facies of Jiyang depression,which makes it difficult to predict reservoir sandstone.At the same time,because of the low resolution of the original seismic data,the application of conventional seismic interpretation technology is not ideal for the prediction of fluvial sandstone reservoir,which restricts the effective exploration of this type of reservoir.In this thesis,a set of systematic improved methods are applied for prediction of fluvial sandstone.Firstly,an improved Morlet wavelet is proposed for frequency division reconstruction of seismic data.On this basis,some seismic interpretation techniques such as seismic facies analyzing,seismic sensitive attribute analyzing and strata slice analyzing are used to quantitatively interpret the distribution of fluvial sandstone.Combined with the oil-bearing characteristics of the sandstone,it can provides the direct favorable reservoir targets for exploration and deployment.Five achievements of this thesis accomplished:(1)the dominant frequency of seismic data of the Lower Guantao Formation is determined,and the dominant frequency is adopted for frequency division reconstruction of the three-dimensional seismic data,so the resolution of seismic data has been improved;(2)the high resolution sedimentary cycle of fluvial thin sandstone of the Lower Guantao Formation in Zhuanghai Area is divided by wells information and seismic data and the high resolution sequence stratigraphic framework is established.At the same time,two typical seismic facies are identified,and the general development position of the sandstone is determined by the filling facies,which lays a foundation for fine interpretation of the fluvial sandstone;(3)based on the high resolution sequence stratigraphic framework and seismic frequency division reconstruction,the seismic sensitive attribute test is carried out to determine the instantaneous amplitude attribute as the sensitive attribute,and the prediction accuracy of sandstone thickness is improved by 12% compared with the original seismic data;(4)the development position of skeleton sandstone is predicted by integrated strata slices;(5)based on the "double-fault reservoir control mechanism",this thesis studies the oilbearing characteristics of fluvial sandstone,classifies three types of reservoir forming modes,and puts forward three favorable reservoir objectives.