Most Negative Curvature Attribute application for Regional Faults study-A review.

English Abstract:

Attribute significance no one can deny. It has given a new dimension to study the subsurface. Besides data interpretation this is a robust technology which every geoscientist is using nowadays. But a careful selection of few parameters and attributes has to be made in order to achieve good results. Among a vast range of attribute that are now available in the market there are few which are most significant. Yet alone they provide promising results related to some features such as faults which others can only give in a combination. Most negative curvature is one of them. It gives a clear picture of regional fault trends at various Time slices. This helps to understand the faults occurrence at various subsurface levels. The projection of attribute at Horizon slice makes it easy to understand the various syn-depositional and post depositional fracture or faults of the rock formation. To study other features related to amplitude anomalies the combination of several attributes is recommended. While picking a certain set of attributes a careful choice has to be done and also other features as display color make an individual impression while interpreting.

The present study relates to a fault system delineation by Time slices displays in figure1. The faults are trending northwest-southeast. At 1.1 sec the faults are not very prominent (fig.2 a) but gradually at deeper levels their presence is well defined (fig 2, b-f). In figure 2b the set of faults 1 and 2 appear which extend to south in fig 2c at time slice 1.28. To observe the faults closely the time slices are taken at a short interval. Another set fault 3 appears in north (fig 2d and 2e). This diminishes at time slice of 1.5 sec (fig 2f). Overall faults become less prominent at 1.6 sec (fig 2g) and another set 4 becomes visible at time slice 1.7 sec (fig 2h).

The color choice also helps in the visibility of structures. The selected color scheme shows the area is segmented by northwest-southeast faults. This display is very good to show overall regional trends of faults. When the color scheme is changed for a time slice display at 1.2 sec the visibility of some local level faults and fractures is enhanced (figure 3). The local and regional level faults are correlated by most negative curvature at time slice 1.51 with faults on Inline and Crossline (figure 4)