Prediction Of Reservoir Thickness Based On The Characteristics Of Time-frequency Spectral

In the field of oil and gas exploration,it is of great significance to carefully describe the horizontal distribution and vertical extension of the reservoir.In China,the number of ultra-large contiguous oil and gas reservoirs is few,but there are a lot of unevenly distributed and thinner oil and gas reservoirs.Therefore,for the oil and gas fields that have been proved and planned to be developed,it is extremely important to more accurately depict the thickness of the reservoir and identify the location of the thinner reservoir,which is also a key factor in saving production costs and reflecting the value of oil and gas reservoirs.Nowadays,the way of conventional reservoir thickness identification is timefrequency analysis,seismic attribute inversion,etc.The method of predicting reservoir thickness in this paper is based on time-frequency characteristics.Because thinner reservoir have severe tuning effects,it is difficulty to determine the location of the reservoir interface.In response to this problem,this paper analyzes three quantitative prediction methods of reservoir thickness based on time-frequency characteristics.(1)Method of instantaneous attribute.Retrieve the thickness of the reservoir through the fitting relationship established by the instantaneous frequency value extracted by the generalized S transform and the reservoir thickness obtained from the log interpretation.(2)Method of extreme frequency at the point of the spectral.The time thickness of the reservoir can be obtained by determining the reciprocal of the frequency of the extreme point of the spectrum.(3)Reservoir thickness prediction method based on instantaneous phase in time-frequency domain.Because the phase spectrum contains reservoir thickness information.The reservoir thickness is calculated by transferring the spectrum of seismic records to the phase spectrum to establish a phase objective function.By introducing the generalized S transform time-frequency analysis method,the calculation result of the phase objective function on the reservoir thickness is more accurate.The test results of the model show that result of the method of extreme frequency at the point of the spectral and the method of instantaneous attribute both have a certain degree of calculation error,but the calculation result based on the generalized S transform phase objection function is relatively accurate in a noise-free environment.In the application of actual seismic data,the reservoir thickness prediction results based on impedance statistics and the three methods based on the characteristics of timefrequency spectral in this paper are compared with the accurate thickness results.From the comparison information,it can be seen that the reservoir thickness information predicted by the method based on time-frequency characteristics has a good accuracy.More accurate reservoir thickness information can be obtained by using multiple methods.The methods of analysis of reservoir thickness based on the characteristics of time-frequency spectral have important implications in the field of oil and gas exploration through the analysis of this paper.