Research On Reservoir Prediction Technology Of Box 8 In Section 59 Of Sulige Gas Field

With the deepening of the oil and gas exploration and development,the tight sandstone gas has shown great potential for development,it plays an important role in making up for the shortage of conventional natural gas.Owning the richest reserves and highest output,the Sulige gas field is the largest tight sandstone gas field in China,it plays an important role in the study of tight sandstone gas.Su59 area is located in the west of Sulige gas field,the distribution of gas reservoir in this area is less affected by tectonic action,the key controlling factors are lateral distribution of sand body and heterogeneity of reservoir.The P1h8 member belongs to typical tight sandstone lithologic trap reservoir;the transverse distribution of sand body is wide but changes quickly;the reservoir has multiple levels in vertical,but the thickness of a single sand body is relatively small;gas-water relationship is complex;the low frequency of seismic data is insufficiency.Therefore,it is difficult to improve the accuracy of reservoir prediction.This paper has studied the tight sandstone reservoir of the P1h8 member,combining the information of the geology,seismic,drilling and logging of this region,using impedance inversion and attribute analysis technology,carrying out the study of favorable reservoir prediction.The impedance inversion is used to predict the lateral distribution of favorable sand body;the seismic attribute analysis technique is used to predict favorable sandstone gas bearing area;combining the above results,completing seismic reservoir prediction of the P1h8 member,good prediction result has been obtained.The main achievements of this study are as follows:1.The logging response characteristics of different types are analyzed,when the reservoir has good physical properties and high gas content,it has the characteristic of low impedance,this conclusion provides a basis for the application of impedance inversion to predict favorable sandstone reservoir.2.The seismic response characteristics of different types are analyzed,the relationship between gas production and variation of frequency and amplitude is summarized,it provides a basis for the prediction of favorable sandstone gas bearing area,by using the seismic attributes.3.Using wave impedance inversion technique,the characteristics of high lateral resolution of seismic data and high vertical resolution of log data are fully used.He83?He84 gas reservoir is mainly distribute in the relatively low impedance about 9100-10800 g/cm3*m/s,the lateral distribution of the favorable sandstone reservoir is described.4.Spectral decomposition is applied in original seismic data,single frequency seismic data are acquired,the low frequency shadow is analyzed,stratigraphic absorption profile,low frequency instantaneous amplitude and high frequency attenuation gradient are calculated,the comprehensive analysis of these attributes is applied,the favorable sandstone gas bearing area is described.5.Combining the results of impedance inversion and attribute analysis,the advantages of each method are comprehensively used to improve the prediction accuracy of the favorable reservoir.