Detecting subsurface faults and their types in oil drilling?

How to detect faults and their types while drilling an oil well? what are the criteria and description ?Detecting subsurface faults and their types in oil drilling?
Subsurface faults are detected through analysis of seismic profiles. They show up as a jump in the reflections, or as an irregular zone. Since seismic profiles will only show differences in depth of reflectors (formation beds), you can't see transform faults directly.





we can see faults directly while drilling too, as when we're drilling away in a horizontal well and suddenly get a different formation. But again, we can't see transform faults.