Carbonate reservoirs are the targets of many drilling programs in the Middle East. One of the challenges in developing these types of reservoir is to mitigate the risk caused by unexpected pore pressure - these pressures can vary dramatically from relatively benign (e.g. Arab C and D Formations) to highly overpressured (e.g. Gotnia Formation, Oman/Kuwait).
A problem arises
however, that existing pore pressure prediction techniques (that were developed for shales
) are being applied to these targets with little consistency. There is a tendency in the industry to use seismic velocity data and porosity-based, shale-centric techniques to predict pore pressure directly in carbonates. This approach, at best, will only ever give a local, empirical fit as internally carbonates are too variable.
An approach looking at the basin history is advised, as the paleo-history of a carbonate will dictate its current pressure regime, coupled with sensible pressure modelling in any associated shales, and understanding of elastic (Poisson’s Ratio, Young’s Modulus, Vp, Vs and Rho) and mechanical (UCS, coefficient of friction) properties of the carbonates.
Click to register for webinar on 19th April at 9am (BST).