## 4 Shortlisting of Seismic Attributes
### Thinned Fault Likelihood  
TFL is a novel innovative fault attribute that yields precise and exact discontinuities. It is defined as a power of semblance, and it has a range between 0 and 1. It generates seismic volumes with razor-sharp edges that are very well suited for structural interpretation. The algorithm detects the range of fault dips to find the maximum likelihood to delineate the fractures in the area of interest and gives razor-sharp fault images on vertical sections and horizontal slices. A comprehensive study by [35] proposed a method of fault likelihood to recognize locally planar discontinuity. The TFL technique measures the likely combinations of dips and strikes to obtain a solitary direction, which gives the maximum fault likelihood for every sample image [35]. The TFL for every sample was documented in TFL images across the whole seismic cube, as shown in Figure 7. The inserted slice on the resultant TFL cube at 2176 ms showed that the area was affected by small scale fractures. The results showed that maximum fractures were present at the top from 600 to 900 ms, which were large scale fractures of higher lengths. Additionally, the TFL values were at minimum below 3000 ms, which showed the presence of relatively fewer fractures of a very small scale. The discontinuity features were further observed using the fault discontinuity attribute volume to create and rank the fracture bodies. The resultant TFL volume was used as input for estimating the fracture bodies using the VCF. The VCF is an effective tool to create continuous bodies based on the amplitudes in a stored volume. A voxel is defined as the volume around one sample. The sample's interconnection was computed based on amplitude criteria and geometrical spreading settings. The voxel connectivity filter was applied using the envelope of the amplitudes, which were higher than the 0.6 value; the envelope was defined for the fracture bodies to be computed. The propagation was done in all directions (26) using the six faces, twelve edges, and eight corners adjacent to the current seed. The bodies that were larger than 100 voxels were processed as relatively large scale fractures, and the output volume was processed using the body-size. The results of the generated connected fracture bodies were displayed using the voxel connectivity filter, as shown in Figure 8a. The results showed the orientations of the connected small scale and large scale fracture bodies. The facture bodies  
Figure 6: Seismic sections showing the major discontinuities: (**a**) full-steered similarity, (**b**) non-steered similarity, and (**c**) FEF-similarity attributes. The FEF-similarity gave the best results. (**d**) FEF-similarity cube. The yellow arrows represent major discontinuities. were oriented mostly in the east-west directions, and large-scale fracture bodies were present at the top, whereas the small scale fracture bodies were present at the bottom of the study area. The fracture planes and sticks were also extracted using the discontinuous TFL volume as input. The fracture planes proved to be quite beneficial in recognizing the sweet spots for prospect evaluation, field development, and future drilling of exploration and appraisal wells [85]. The fractures were interpreted and visualized on the cube as a stick, and all sticks that belonged to one fracture were merged into a single stick set. Thus, a single fracture stick set was comprised of an unordered collection of the interpreted sticks. The minimum TFL value of 0.01 was used in the current study. The minimum value of sticks per fracture was applied, which helped to identify the small scale fractures that had small throws. The minimum vertical overlap rate of 0.6 was used to extract maximum tilted fractures, because a value greater than 0.6 may have extracted maximum fractures with a risk of picking up more noise. The minimum fracture length per z-slice of 250 was applied to extract the maximum fractures with smaller heaves.