Predicting Fracture Connectivity and Density within the Austin Chalk from Outcrop Fracture Maps

WILTSCHKO, D. V., Texas A&M University, College Station, TX, KEVIN P. CORBETT, Marathon Oil Company, Littleton, CO, and MEL FRIEDMAN and JIH-HAO HUNG, Texas A&M University, College Station, TX

Maps at scales of 1:12 to 1:48 of parts of quarry floors in the Austin Chalk reveal the change in fracture density, length, and ordering, with respect to orientation along the trend from Del Rio to Dallas. Area with more marl beds and/or large total percent clay display, in general, more random, more dense, and more

interconnected fracture patterns. Fractures in the vicinity of San Antonio where clay content is low, by contrast, are more widely spaced, longer, and less interconnected than other areas studied. Several of the fracture patterns mapped indicate that the concept of fracture sets may be less useful in the Austin Chalk. The highly curved fracture observed suggests low differential stress and net uniform extension of the Austin Chalk.

AAPG Search and Discovery Article #91006 © 1991 GCAGS and GC-SEPM Meeting, Houston, Texas, October 16-18, 1991 (2009)