In unconventional resource plays, pore pressure plays a critical role in the ability to predict fracture behaviour, and hence in the exploitation of these plays. Yet it is a parameter that is poorly understood, and little work has been done to understand whether it can be predicted in an unconventional setting. The case study presented here shows how the traditional methods (Eaton Ratio and Equivalent Depth) can be used to predict pore pressure using a Pressure Reference Trend (PRT) in-lieu of a Normal Compaction Trend (NCT) that would be used in the offshore environment. The PRT is not linked to the expected compaction behaviour of the rock (as inferred from an NCT) but it is simply an empirical depth trend from which the pore pressure can be predicted using industry standard formulae.

 

Author associations
1 Ikon Science Canada, 2 Nexen Energy ULC