In February's First Break, Stephen O’Connor, Sam Green and Alexander Edwards from Ikon GeoPressure, review the impact of pore pressure on unconventional plays and discuss the challenges of pressure prediction in these plays that currently exist.  The article describes how pore pressure can be calculated once a detailed understanding of the geological model has been built, including the burial history.  The amount of subsidence, duration of unconformities and amount of uplift impacts the pore pressure but the effects can be estimated using some simple assumptions about pore pressure generation and incorporating data from published sources.  In conclusion, the authors state, a robust and accurate geopressure model can be integrated into a complete rock physics and geomechanics analysis of unconventional plays, leading to the development of a 3D integrated mechanical flow simulation, for use in field management and production optimisation.