Last week, I attended “Fractures and Geomechanics,” a one-day short course held in Denver and put on by RMAG. Attendance was surprising: nearly 300 people packed a room at the Marriott hotel downtown to hear John Lorenz, a noted expert, talk about fractures. Of course, fractures have always been important to petroleum geologists. But in these days of unconventional exploration, fractures are of immense interest. They provide permeability to rocks sorely in need of it. I was pleased to see a large number of young people in the audience. John had four tables of core available for inspection, in two corners of the lecture room. One side featured naturally fractured core and the other, induced fractures that were artifacts of the coring and handling process. I found it fascinating, as I never did much work with core during my years in exploration. John gave excellent pointers on the dos and don’ts of fracture interpretation in core. His section on methods to extrapolate surface fractures to the subsurface were also highly useful. And, his photos were wonderful. He had some shots of deformation bands that were amazing, and really brought home the compartmentalization that such bands can cause in an otherwise excellent reservoir. An important take-away point was his assertion that fractures, which may be quite common in the subsurface, can be very difficult to capture in core. Just because you can’t see natural fractures in a core doesn’t mean there aren’t any! --by Peggy Williams, Senior Exploration Editor, Oil and Gas Investor. Contact me at