Seismic Reservoir Prediction Of The Upper Jurassic Suining Formation In Luodai Field

The Luodai gas field is located in the eastern slope of the Western Sichuan depression,and is on the west side of the NNE trending tectonic belt of the Longquan mountains.Because of the long development time of Luodai gas field,it is very difficult to make stable production.In order to solve the problem of stable production,it is urgent to carry out fine reservoir prediction in the study area.According to Suining formation of Luodai gas fieldStrong heterogeneity and rapid lateral variation characteristics in geological and seismic combination as a guide,the integrated use of logging data,well comparative analysis,frequency imaging,seismic attribute analysis,constrained sparse pulse inversion method for seismic reservoir prediction.The calibration in stratigraphic division and horizon interpretation basis,starting from the basic geological research,make full use of logging data,analysis of single well logging facies and sand body identification,with well seismic combination principle,the establishment of the Luodai formation of Suining gas field smallcomparedlayer frame,at the same time,the use of frequency imaging techniques,characterization of Luodai formation in Suining area,sedimentary facies distributary channel shape and boundary.Using seismic data to extract the amplitude attributes of Suining formation in Luodai gas field,and to describe the distribution characteristics of sedimentary facies by the comparison of small layer contrast frame,channel characterization and extraction of amplitude attributes.On the basis of the interpretation of horizon calibration,the fine structure is described,and the structural errors are analyzed.Wave impedance inversion of Suining group Jsn₁^1-2 using constrained sparse pulse inversion technique.The study of sedimentary facies,fine structure characterization and wave impedance inversion results can be used to predict the distribution of favorable facies belts.In the end,the method of fine prediction of Luodai reservoir is formed by the combination of Geology and geophysical exploration.The main achievements are as follows:?1?Using the seismic data,the precise calibration of the horizon and the time depth conversion,the structural map of the Suining formation of the Luodai gas field Jsn₁^1-2 is compiled.The whole is from the north to the nose anticline,high in the south,north to the East,but in the LS9 D well and the LS36 D well,there is a significant North West groove,L653-LS1 line in the groove.There are three regions with higher tectonic positions.?2?According to the logging data analysis,single well logging well correlation analysis using resform software,combined with the analysis of seismic frequency technology and seismic attributes,been compiled zone in Suining group Jsn11-2 sedimentary facies.Sedimentary microfacies include subaqueous distributary channel,interdistributary bay,mouth bar,crevasse splay,underwater distributary channel is the most developed,there are 7 large scale distributary channel,estuary dam development degree is low,only in the south central area development.?3?According to the known gas reservoir sandbody logging data,through the forward analysis,the Suining reservoir response model,the seismic response characteristics of the high-quality reservoirs is low frequency and high amplitude,low impedance on the seismic reflection characteristics,mainly for the lens reflex.The seismic response characteristics of the favorable reservoirs are mainly lenticular or localized.The seismic response characteristics of thin and poor reservoir are often characterized by weak reflection,and the lensing characteristics are not obvious.?4?Using the method of constrained sparse pulse inversion,the wave impedance inversion of the Suining formation is carried out.According to the analysis,the inversion parameters of the study area are selected.In the middle and northwest of the study area,the wave impedance is low,the Jsn₁^1-2 sand reservoir is more developed,the whole work area is developed,and the reservoir property is generally better.?5?According to the accumulation and accumulation degree of oil and gas,the favorable facies belts of Suining formation gas reservoirs are divided into 4 types: the first kind enrichment area,the second kind favorable area,the third kind favorable area and the fourth kind sand body development area.20 wells,8 wells have been drilled and tested,and 8 wells have been adopted.