Fracture spacing and orientation distributions for two-dimensional data sets

A new, automated method is developed for the measurement and display of fra cture spacing and orientation from two-dimensional (2-D) fracture maps. Sep arate histograms of fracture spacing are calculated at different orientatio ns through the 2-D data set. The histograms for all orientations are plotte d together, reducing the biasing effects associated with one-dimensional (1 -D) sampling of a fracture population. Quantitative measurements of fractur e strike anisotropy and fracture density are incorporated in the plot. No p rior measurements are needed of parameters such as fracture spacing, orient ation, or width. The data do not have to be preprocessed into a numerical v ector format, saving time and reducing user bias. The method retains the re lative frequency of different ranges of fracture spacings, which are lost i n other fracture frequency measures such as fracture intensity/density. Thu s the presence of any dominant (rather than average) fracture spacing and f racture clustering is highlighted. The method provides a quantitative, stat istically unbiased representation of fracture orientation and spacing and i s illustrated on synthetic and real fracture data sets at a range of scales (from meters to tens of kilometers), Its application to a seismic energy s cattering problem is also discussed.