Influencing Factors And Compensation Methods Of Middle And Deep Seismic Frequency Band

The oil and gas content in the middle and deep layers is very rich,but the middle and deep layers are buried deeply,making exploration difficult.The seismic resolution is usually low,which has become a huge obstacle to the exploration and development of oil and gas in the middle and deep layers.The frequency of seismic waves is an important factor affecting seismic resolution.Generally,the higher the main frequency and the wider the frequency band,the higher the seismic resolution.However,the actual underground medium is not fully elastic and can cause absorption and attenuation of seismic waves(especially high-frequency components).At the same time,due to special geological factors and other factors affecting the middle and deep layers,conventional velocity analysis cannot obtain a good velocity model.The seismic data after migration imaging is very blurry and difficult to identify,the main frequency of seismic waves decreases,the frequency band narrows,waveform distortion occurs,the event axis is discontinuous,the stratigraphic contact relationship is unclear,the seismic response is unclear,the structure is difficult to implement,seriously reducing seismic resolution,and further oil and gas interpretation cannot be carried out.In response to the above issues,this article first analyzes and summarizes the possible influencing factors of seismic frequency bands from both geological and seismic aspects.Then,it studies the characteristics of the middle and deep layers in a specific target area and the influencing factors of seismic frequency bands.Based on the actual geological situation of the selected target area,through modeling,forward modeling,and migration imaging in the middle and deep layers,the focus is on analyzing the impact of shallow gas and low-speed mudstone on frequency bands.Then,through the viscoacoustic forward modeling and migration imaging,the influence of medium absorption and attenuation on the frequency band is emphatically analyzed.Attenuation compensation can restore the main frequency,frequency band,and waveform of seismic waves,improve seismic resolution,and is of great significance.This article uses two inverse Q filtering methods to compensate for absorption attenuation of simulated and actual data,and analyzes the compensation effect.The results show that the imaging results compensated by the stability factor method and the hybrid method have achieved a certain degree of recovery in the blank reflection area compared to the viscoacoustic imaging records.Both methods have a certain recovery effect on the amplitude,main frequency,frequency band,and waveform of seismic waves,improving the resolution of seismic data.