True Depth Conversion

Question 1

Briefly state 4 expected deliverables of Depth Conversion Project

Answer 1

• Seismic data volume (SEGY) in depth domain (not time)
• maps/computer grids of depth from seismic and wells
• velocity model in 2D profile or 3D cube data volume
• what are the possible errors

Question 2

Explain depth migration (be brief)

Answer 2

imaging issue

imaging of subsurface structure

Question 3

Explain depth conversion (be brief)

Answer 3

calibration issue

calibration of seismic to subsurface model.

Question 4

What is the purpose of Depth conversion ?

Answer 4

to remove structural ambiguity inherent in time and verify structure

Question 5

List 2 types of depth conversion

Answer 5

direct time-depth conversion

velocity modeling for depth conversion

Question 6

What are the 2 criteria to evaluate accuracy and reliability of depth conversion

Answer 6

tie existing wells (this confirms if velocities are accurate)
accurately predict depths at new well locations (blind test)

Question 7

What’s another reason for velocity misties besides velocity anisotropy

Answer 7

non uniqueness of velocity model

Question 8

What’s a possible solution to the fact that non-uniqueness can cause velocity misties?

Answer 8

incorporate well data into velocity model . You can control the seismic data so it is more accurate

Question 9

What are stacking velocities picked on the “fast” side of the velocity function?

Answer 9

to discriminate against multiples