A method for predicting fracture-enhanced permeability in regions of 'flat-lying' strata.

摘要

Scope and method of study. The ability to predict relative fracture density in the subsurface is important to hydrologic investigations and to other endeavors involving earth resources and the environment. Six remote sensing mapping techniques were compared with detailed oil and gas production maps of a fracture controlled reservoir in the Sooner trend of Oklahoma to ascertain if a statistically significant correlation exists between the remote sensing phenomena tested and fracture density in the deep subsurface. Where applicable, linear correlation coefficients between surface and subsurface data were calculated and tested for validity using ANOVA and t-test of correlation.;All six sets of maps showed some relationship with subsurface structure and isopachous features. These relationships were not uniform, and no simple statistical correlation appeared feasible.;Findings and conclusions. Five of the six sets of maps tested did not show any general correlation. However, a map of lineament-intersections derived from drainage lineaments did show a statistically significant correlation with fracture controlled Meramec-Osage oil and gas production. The relationship has a linear correlation coefficient in excess of.8 with ANOVA and t-test of correlation alpha-limit-of-error less than.01. This demonstrates a statistically significant correlation exists between surface drainage lineaments and relative fracture density at depths up to 2,500 meters. This correlation exists despite the presence of unconformities and "shale seals" between the surface and the target formation.