Abstract

The thickness of amplitude attribute is defined as total time length (in milliseconds) of amplitudes that exceed a threshold value of amplitude in the target layer within 3-D data volume. The threshold value is estimated by analysing the reflection response of the subsurface layers. It depends on impedance contrast, geology and reflection wavelet characters (polarity, phase, frequency, amplitude etc.). This attribute extraction was applied for pre-drill estimation of time-thickness of thin sandstone pay in the area. The thin pay was identified through integrated interpretation of 3-D seismic data. The geologic thickness (in meter) of the thin pay was estimated from thickness of amplitude through multiplication by interval velocity (m/s) of the pay. The pay thickness is one of the important parameter along with area, porosity and saturation for estimation of hydrocarbon potential of the reservoir and decision on drilling of wells. In this study the thickness estimates were found valid with accuracy of more than 80 % after drilling the well for discovery. Concepts, methodology and relative merits and novelty of the method are discussed in the paper