Prediction of massive hydraulic fracturing from analyses of oriented cores : Logan, J M; Teufel, L W Proc 19th US Symposium on Rock Mechanics, Stateline, Nevada, 1–3 May 1978, V1, P340–344. Publ Reno: University of Nevada, 1978

Abstract

An attempt has been made to predict the orientation of massive hydraulic fractures stimulated between depths of 2316 and 2464 M within the Muddy J formation of the Wattenberg Gas Field, Colorado. Predictions were based upon a study of the properties of 3 oriented cores and 2 unoriented cores. A preferred orientation of fractures induced in point-load tests is found for all 5 wells. The second phase involves investigation of the composition, grain size, microfracture orientation, crystallographic orientation, grain dimensional orientation, and residual strain. It is concluded that the fractures oriented at 335 on the east and west sides of the field are primarily controlled by the dimensional orientation of quartz grains, while those in the center of the field having an orientation of 110 are controlled primarily by the residual strain. Subsurface geology shows a buried fault trending northeast through the center of the field, postulated to have influenced the distribution of residual strain. In the eastern and central wells, good agreement was found with the predictions from the core analysis. 10 references.