Technology Of Seismic Inversion In Pu-362Area Of The Yongle Oilfield Forecast

In prospecting for seismic work early stage, geological task is to find construction and traps,mainly find out fluctuation alternation of reflection interfaces,and the seismic information mainly is the traveling time of the reflection layer,mainly working content is tectonic explanation.With the deepening of exploration degree,the core of reservoir geophysical is to study the heterogeneity of reservoir,and it’s geological mission is to make a prediction of the reservoir,and its mainly task is cross range changes of the reservoir characteristics,and the workcontent is based on seismic inversion of reservoir and information extraction,then has comprehensive explanation,therefore,wave impedance inversion technologyin seismicexploration has a important position.Seismic inversion mainly included prestack and post-stack inversion.At present,post-stack inversion has a widelyapplication,post-stack inversion mainly included seismic trace integration,recursion inversion,model inversion,Geostatistics inversion.This paper analyze the development of inversion technology, and has the further study on Recursive Inversion, Model Inversion, Geostatistics Inversion, discusses some problems on these inversion technology, and compares the advantages and disadvantages of these inversion. Seismic inversion technology changes seismic data into lithology data; it integrates the resolution of the wells in the vertical and the continuity of the seismic in the horizon. Lithology data can contrast with wells directly, and can be interpreted on the lithology layer.The method of constrained sparse spike inversion supposes that the reflectio ns coefficients of strata are sparse.A rapid trend-constrained pulse inversion calc ulation is adopted,using the seismic interpretation horizon and logging-constraint to control the trend and scopeof wave impedance.The pulse calculation can obta in the wide-band result,The inversion result is faithful to seismic data,simultaneo usly; the constraint of logging and geology can replenish the component of lo w and high frequencies,The vertical resolution is heightened.comparatively to the conventional seismic data,The technology of Geostatistical inversion adopts the correlation feature existing between seismic wave impedance and reservoir prope rty,and organically combines seismic random inversion (simulative annealing met hod,etc)with geologicalstatistical simulation technology (co-kriging,Gauss and othe r algorithms),The technology can use seismic,geologic,logging and otherdata to t he maximum limit. The result of reservoir property description can coincide toget her with geological statistics inversion.The technology reflects the anisotropism a nd uncertainty of reservoir property spatial distribution very well. The results of Geostatistics Inversion technology are more fit the geology conditions,because t hey combine the parameters of the structure and randomicity of the reservoir in the spatial.Therefore,Geostatistic Inversion technology is applied at middleand fi nal stage of development.At the same time,Many results with equalprobability ar e produced by Geostatistics Inversion technology,so we must analyze the results and select the best result.Yongle oil field Pu362th area located in the southern part of the oilfield.It is in the junction of Datong,Daqing,Zhaozhou,Zhaoyuan district.In the east is Zhaozhou oilfield and in the north is Taipingtun oil field.Regional structure is Daqing Changyuan second-order tectonic belt toward the south tower structure for Putaohua outspread part. From the seventies to early eighties, Yongle oilfield had been not developed because its poor reservoir properties and complex relationship of oil-water relative to Changyuan’s. Taizhao area’s undeveloped reservation is1003.06×104t,oil-bearing area is60.8km2,premiliary planning develop beneficial block during the second five,which the Pu362th development area is16km2,reservation is270x104t, Pu362th oil testing received6.305t industial oil by MFEⅢ,which confirmed this block has a certain potential development.But now drilled well’s average effective thickness is poor,the develop of reservoir is thin,poor and unsTab.. So carry out the study of reservoir character to explore the effective develop of this block,which provides technical reservers for the next block development and reduces development risk.The thickness of Putaohua oil group is very thin, about35meters, thin sand-shale interbed, single sand layer thickness is1to2meters. The Seismic data is bits and pieces, both have3D datas and2D datas, the resolution of Constrained sparse spike inversion is low, can not recognize the sandstone which is lower than10m; the resolution of Geostatistical inversion is high, can recognize2to6meters sandstone. Constrained sparse spike inversion is the most basic inversion method, is also the basics of Geostatistical.These inversion technologies are applied to survey of Pu-362area of the Yongle oilfield. Different values of a same parameter are taken to analyze and compare the result and the affect of a same inversion technology.I analyze advantages and disadvantages of this inversion technology and reach some conclusions, and draw a conclusion of how to select the value of some key parameters.In the case study part, the applicability of several seismic impedance inversion methods has been compared. Example shows how to apply seismic inversion properly in the complicated structured reservoir. According to the drilling and geology information, inversion impedance data has been applied to reservoir prediction.Based on application of above technices, the interest targets for drilling oil are argued and point out, meanwhile, a set of seismic predicting technices dealing with thin sheet-likelenticular bodies is summarized.