Geology Reference
In-Depth Information
a)
+
Stack Response
Brine Oil
Gas
Sand 1
Sand 2
Stack Response
brine
oil
gas
Brine Oil
Gas
Sand 2
-
+
Stack Response
Sand 1
Sand 3
Brine Oil
Gas
Sand 3
-
Intercept
b)
sand 1 oil
sand 1 gas
sand 2 oil
sand 2 gas
sand 3 oil
sand 3 gas
sin
2
Figure 5.36
The effect of pressure on AVO. Sands 1 and 3 are normally pressured whilst sand 2 is overpressured by around 500 psi: (a)
intercept/gradient crossplot illustrating the variation in seismic signatures (including Class 1, 2p, 2 and 4) at the top sand, (b) absolute
amplitude difference plot showing how all hydrocarbon sands show increasing amplitude difference with angle.
81
