Investigation of the influence of stress shadows on horizontal hydraulic fractures from adjacent lateral wells

Abstract

Production efficiency from low permeability shale gas reservoirs requires techniques to optimize hydraulic fracture (HF) completions. This may be complicated by the presence of high horizontal in-situ stresses that result in horizontal HF, for example in parts of the Western Canadian Sedimentary Basin in northeastern British Columbia. One strategy involves the simultaneous or near simultaneous hydraulic fracturing of adjacent lateral wells to maximize the fracture network area and stimulated reservoir volume. However, changes to the in-situ stress field caused by an earlier HF on subsequent HF are not accounted for in traditional hydraulic fracturing design calculations. Presented here are the results from a set of transient, coupled hydro-mechanical simulations of a naturally fractured rock mass containing two wellbores using the discontinuum-based distinct-element method. The results demonstrate the influence of stress shadows generated by a HF on the development of subsequent HF from an adjacent well. It is shown here that these interactions have the potential to change the size and effectiveness of the HF stimulation by changing the extent of the induced fracture around the secondary well. Also, the influences of in-situ stress and operational factors on the stress shadow effect are investigated and their effects on different operational techniques are studied.