|
| Frequency range focused | Technique used | Advantage | Disadvantage |
|
| Modeling frequency: 50–60 Hz [25] | Spike deconvolution for low frequency modeling | (i) Low-cut filter is used to attenuate low frequencies.
(ii) Defining technique produces better P-wave and S-wave seismic section. | (i) Need for recovery of broad signal bandwidth.
(ii) Poor wavelet extraction and its structure. |
|
Modeling frequency: 1 KHz
Acquired seismic frequency: 12 Hz
Reflectivity at 40 Hz [26] | (i) Ultrasonic experiment
(ii) Seismic data analysis | (i) Signal is reflected from a thin, water- (Sw) or oil-saturated (Sh) layer.
(ii) Frequency dependent amplitude and phase reflection attributes have been utilized for observing and identifying thin liquid saturated layers. | (i) Strong attenuation in the layer affects summation of multiples.
(ii) Layers with higher attenuation create travel time delays, which increase as frequency approaches zero. |
|
| Missing frequency: 5–10 Hz [27] | (i) 3D acoustic inversion
(ii) Variable depth streamer: seismic data acquisition
(iii) 3D elastic inversion: comparison technique | (i) Variable depth streamer for data acquisition is better for inversion and provides missing low frequencies directly.
(ii) Left side lobe of the wavelet is proposed to reduce/less interference in the seismic signal results in less ambiguity in inversion. | (i) There is variation in resulting inversion due to high variation in acquisition frequency.
(ii) Broadband inversion may cause obtained results outside the target zone. |
|
Reflection: <15 Hz
Amplitude: 40 Hz [28] | (i) AVO attribute analysis
(ii) VSP analysis | (i) Imaging at low frequencies results in robust amplitudes for individual frequency components of propagating wavelet.
(ii) Frequency based seismic imaging permits characterizing the subsurface fluid reservoirs. | (i) Quantitative analysis of AI (as frequency) requires NMO stretching.
(ii) Conventional seismic processing software does not work as target-oriented processing. |
|
