Fracture porosity in reef talus of a Miocene pinnacle-reef reservoir, Nido B field, the Philippines.

Abstract

Analysis of a core of the Nido B oil field offshore Palawan, Philippines, shows that: 1) fore-reef talus is susceptible to extensive marine cementation, which can destroy its reservoir potential unless secondary porosity forms; 2) small fractures can form a significant reservoir and conduit capable of producing in excess of 10 000 barrels of oil per day; and 3) when associated with interbedded shales, fore-reef talus is susceptible to extensive fracturing by either overpressured fluids or flexure due to compaction. The former process seems to have been more important in this core. -J.M.H.