Page 173 - Hydrocarbon Exploration and Production Second Edition
P. 173
160 Data Interpretation
top of reservoir
5′
net
10′
net 20′
bottom of reservoir gross
productive N / G = 15 / 20 = 0.75
non-productive
Figure 6.46 Net to gross ratio.
Figure 6.47 The gamma ray log.
laminated rocks where shale and sand beds are very thin as it is difficult to calculate
N/G from logs.
The N/G ratio is usually not constant across a reservoir and may change over quite
short distances from 1.0 (100% reservoir) to 0.0 (no reservoir) in some depositional
