**Abstract**

The technology of multiple hydraulic fracture stimulation in horizontal wells has trans‐ formed the business of oil and gas exploitation from extremely tight, unconventional hydro‐ carbon bearing rock formations. The fracture stimulation process typically involves placing multiple fractures stage-by-stage along the horizontal well using diverse well completion technologies. The effective design of such massive fracture stimulation requires an under‐ standing of how multiple hydraulic fractures would grow and interact with each other in heterogeneous formations. This is especially challenging as the interaction of these fractures are subject to the dynamic process of subsurface geomechanical stress changes induced by the fracture treatment itself.

This paper consists of two parts. Firstly, an idealised analytical model is used to highlight some key features of multiple hydraulic fractures interaction, and to provide a quantifica‐ tion of 'stress shadow'. Secondly, a new non-planar three dimensional (3D) hydraulic frac‐ turing numerical model is used to provide an insight into the growth of multiple fractures under the influence of subsurface geomechanical stress shadows. Attention is given to studying the height growth of multiple fractures.
