Abstract:

Seismic frequency-division is to transform seismic data into different frequency domains via the Discrete Fourier Transform(DFT)or the Maximum Entropy Method(MEM),and is generally used in the predication of thin reservoirs.Based on the thickness and distribution of reservoirs,seismic primary frequency can be extracted through selecting appropriate parameters of time window.Plane changes of seismic primary frequency can then be used to detect edges of sedimentary bodies,thus providing reliable evidences for the study of fan-delta evolutionary process.The relationship of seismic primary frequency and reservoir thickness can also be employed to calculate thicknesses of thin reservoirs.By applying the technology in the analysis of the Jiufetang-Shahai Formations in J2 wellblock of the TLG Oilfield,where deposits of fan-delta facies are developed,the horizontal distribution and vertical evolution pattern of the fan-delta in the research area is defined and the changing characteristics of the source near the southern boundary faults during different times are determined.This field application shows that the technology eliminates the uncertainty of conventional methods for predicting the boundary of sedimentary facies and greatly enhances the accuracy of seismic facies recognition.

Key words: sedimentary boundary, fan delta, frequency-division technology, reservoir thickness, reservoir prediction