2008 Alum


Ezer Patlan

Ezer Patlan


Years participated in RESESS:
2007 →
2008


An Overview

Drilling induced Fracture (DIF) characterization and stress pattern analysis of the Southern McMurdo Sound (SMS) Core, Victoria Land Basin, Antarctica

Academic Affiliation: Senior, University of Texas at El Paso, Mathematics
Science Research Mentors: Terry Wilson – Ohio State University; Cristina Millan – Ohio State University
Writing and Communication Mentor: Kelly Carroll – Ohio State University
Community Mentor: Matthew Beldyk - UNAVCO


Abstract

There is a significant lack of data about present-day stress fields in Antarctica. Stresses provide valuable information about the forces acting on tectonic plates. In Antarctica, stresses may be related to ridge forces such as rifting and/or uplifting, to ice loading/unloading-related processes, or both. This project studies drilling induced fractures from core recovered in the Victoria Land rift basin of Antarctica. Drilling induced fractures form ahead of the drill bit during drilling from stress imbalances due to the removal of excess weight pressure around the rock. Because horizontal stresses strike parallel to the planes made by drilling induced fractures, they can be used to measure modern-day stress fields. Whole core images obtained during core logging by digitally scanning the outside of the core are stitched into longer intact intervals. Drilling induced fractures in the core are ‘picked’ to obtain their azimuth. Magnetically oriented acoustic images of the inside of the drill hole are then compared side by side with the stitched whole core images and visually scanned for matching features. Once the same set of fractures is found in the core and the borehole, it is then possible to rotate core images to match the orientation of the borehole image. This will produce a core image with all the fractures in that interval re-oriented to true north. This final orientation of drilling induced fractures in the core will thus provide the direction of maximum horizontal compressional stress in this area.