4.2 Methodology for diffraction separation for high-resolution imaging: Real field data

Non-migrated offset collection data was on condition that for this project. The initial processing, including the sorting of the common midpoint offset (CMP) collection, was performed to obtain the seismic section of the stack. The following processes were implemented in the sorting process:

Advance Wave Modeling and Diffractions for High-Resolution Subsurface Seismic Imaging DOI: http://dx.doi.org/10.5772/intechopen.81164

#### Figure 12.

Multiple offsets gather data shows that shallow data is not recorded in the far offset (a) range limited stack of 0–780 m (b) 780–2180 m and (c) 2180–3580 m.

#### Figure 13.

Amplitude decay with offset is recorded (a) 0–780 m, (b) 780–2180 m offsets and (c) 2180–3580 m offset stack, signal-noise ratio and amplitude is stronger in the near offset.


#### Figure 14.

Actual input data of the Malaysian basin. Treated with careful diffraction treatment and stacked data prior to migration: Sarawak Basin, carbonate accumulation structure.

Figure 15.

(a) Predicted dip field of data shown in Figure 14, and (b) texture computed by convolving field number with the inverse of plane-wave destruction filters.

Advance Wave Modeling and Diffractions for High-Resolution Subsurface Seismic Imaging DOI: http://dx.doi.org/10.5772/intechopen.81164


Figure 14 shows a 2D line extracted which is an unmigrated seismic from a carbonated field in the Sarawak Basin. It has been carefully treated using preimaging procedures. The diffraction separation method was then extended to preserve the diffractions in the actual data. Figure 15a shows the estimated dip components of the data, which help identify tilt faults and pinches, while Figure 15b shows the corresponding texture [36] obtained by convolving a random number field with the inverse of The destruction by plane wave filters The latter was built

Figure 16. Unspoiled diffractions after the application PWD filtering on stack data.

Figure 17.

Imaging section, including preserved diffraction. The fractures are resolved and the quality of the seismic data is improved.

using helical filtering techniques [37, 38]. The advantage of displaying the texture is to visualize the characteristics of the local plane in the data with the dip. Figure 16 shows the separate diffraction which is the input for diffraction imaging. This diffraction data is migrated separately and merged with the residual data migration shown in Figure 17. The final result of the migration including the diffraction and reflection data which improved the resolution of the data. Inside the red circle on the left side, a major fault is imaged and can be interpreted, further on the right side in the red circle small scale faults are illuminated after imaging.
