reflection

Question 1

What analysis is used for the reflection method?

Answer 1

x^2-t^2

Question 2

How does x^2-t^2 analysis work?

Answer 2

Offsets squared and their associated travel times squared are plotted. The slope of the best fitting line can be used to find layer velocities and the y intercept is used to find layer thickness.

Question 3

What is the echo principle?

Answer 3

energy reflected from boundaries between materials with contrasting seismic impedances

Question 4

Split spread method

Answer 4

• collected with a shot positioned at the ends or center of a geophone array
• ## easy for seismic waves types and optimum time window for reflection events

Question 5

Common offset method

Answer 5

• must determine optimum window
• An initial split shot method can be used to identify window
• Multiple sources correspond to multiple receivers, offset distance equal

Question 6

Limitations of common offset method?

Answer 6

Because this method relies on an optimum source-receiver offset, it is possible that some noise events are misidentified as a reflection.

Question 7

Common depth point method

Answer 7

• primarily used in exploration due to its higher cost
• provides superior reflection profiles due to its ability to remove or “stack” coherent noise
• objective is to gather traces collected at different source-receiver offsets which share the same reflection point
• Advanced acquisition and processing strategies are needed

Question 8

Applications of the reflection method

Answer 8

• Hydrocarbon exploration and production
  -Near-surface applications
  image aquifer systems, abandoned mines, proposed landfill sites, and glaciers
• Crustal and lithospheric imaging