Advances in Seismic Fault Interpretation Automation

Randolph E.F. Pepper
Schlumberger, Stavanger, Norway

Since the first seismic trace was computer-rendered, automatic interpretation has been the panacea of the geo-science community. Twenty years later, we still struggle for a reasonable automatic interpretation in structurally challenging areas.

While automated horizon tracking has become quite elegant, correlating across significant fault displacements remains an obstacle. Algorithms require human intervention to guide the tracking in newly encountered fault blocks. Constraining the horizon tracking to honor pre-existing faults helps, and knowing the fault displacement further enhances this process.

Advances in edge-detection algorithms have allowed direct illumination of faulting and seismically detectable fractures. These techniques improve manual interpretation, but only represent an entry point for automatic extraction of faults.

For some geologic plays, re-sampling of the enhanced edge attribute into a geologic model property is a simple and effective method of un-biased automated fault interpretation. Explicit methods to extract fault surfaces can utilize an automatically picked horizon in-directly through analysis of “non-picks” and gradient trends, followed by spatial correlation for vertical connectivity. Alternatively, using the familiar techniques of seeded auto-picking, on an edge volume, shows great promise. Flexible editing is essential with these methods.

Finally, we examine the recent work on fault system interpretation, which provides a semi-automation of fault interpretation, elevating the interpreter's task to the analysis of fault systems. Incorporating new multi-horizon classification or displacement attributes allow inference about surface connectivity with fault throw. The final assembly of these advanced methods as “bread and butter” interpretation mechanics, while not completely in place, is visible on the horizon!

AAPG Search and Discovery Article #90039©2005 AAPG Calgary, Alberta, June 16-19, 2005