Reservoir geophysics exercises
Exercise 11-1. Derive equation (2a) for the Fresnel zone using the geometry of Figure 11.1-3.
Exercise 11-2. Refer to Figure 11.4-1a. Consider a surface multiple from the first reflecting interface. Trace the traveltime on the VSP diagram in Figure 11.4-1b. Multiples do not reach the downgoing wave path; thus, they can be eliminated by corridor stacking.
Exercise 11-3. Refer to Figure 11.4-1b. Should the slopes of the downgoing and upcoming waves associated with a layer be the same in magnitude?
Exercise 11-4. What procedure does CMP stacking correspond to in the f − k domain?
Exercise 11-5. Sketch the traveltime response for a point scatterer on a zero-offset VSP record.
Exercise 11-6. Consider a CMP gather with a single reflection event. Suppose you have applied hyperbolic moveout correction using equation (90) and discovered that the event is not flat for all offsets. Instead, the moveout-corrected event may have one of the three shapes shown in Figure 11.E-1. Match each of the curves A, B, and C with the following three possibilities:
- You have applied hyperbolic moveout correction using an erroneously low velocity in equation (90).
- You have applied a second-order moveout correction (equation 3-4b) to an event that has a fourth-order moveout behavior described by equation (3-5a).
- You have ignored anisotropy in moveout correction described by equation (92).
Figures and equations
Figure 11.4-1 Vertical seismic profiling geometry. (a) Raypaths and (b) associated traveltimes (see text for details). Static correction amounts to mapping traveltime associated with raypath ABC to traveltime associated with raypath ABC + CD; the NMO correction amounts to mapping traveltime associated with raypath ABCD to traveltime associated with raypath 2DE.
- Introduction to reservoir geophysics
- Seismic resolution
- Analysis of amplitude variation with offset
- Acoustic impedance estimation
- Vertical seismic profiling
- 4-D seismic method
- 4-C seismic method
- Seismic anisotropy
- Mathematical foundation of elastic wave propagation