The technology of multi-stage, multi-frac horizontal wells (MFHW) is arguably the most important technology that unlocks the potential of unconventional shale gas and liquid rich shale oil systems. The fracture stimulation process involves placing multiple fractures stage-by-stage along the horizontal well using diverse well completion technologies. However, there is still a lack of understanding on how multiple hydraulic fractures would grow and develop in highly heterogeneous rock formations.

Clearly, the scarcity of adequate fracture stimulation design models has not hindered the successful application of MFHW in exploiting unconventional resources. The technology is typically appraised and continuously improved in the field - made possible because of the large number of wells employed.  This field optimisation process is not always cost effective, and the present low oil price environment acutely points to the need for competent design models that will aid in the application design and optimisation of MFHW.

It is challenging to model the development of these fractures, which are subject to the dynamic process of geomechanical stress changes induced by the fracture stimulation treatment itself, and the interaction with multiple other processes, including wellbore mechanics and fluid mechanics. For practical engineering application, we aim to capture key physical processes in computation models, at least in the ‘first-order’; apply ‘manageable’ numerical approach and rely on appropriate model calibration with field data.

The talk gives a brief overview of one such practical computation modelling approach, outlines the coupled processes that are important, and paints the vision to leverage the model and field data (e.g., injection pressures and microseismic data) to gain better understanding and improve the design of multi-fracture stimulation.