piège récifal

CONT: Tendance du pétrole à remonter en surface en raison de sa légèreté. Un «piège» est donc nécessaire pour le garder prisonnier de sa roche-réservoir : - Piège structural : coince le pétrole sous une couche de roche imperméable. - Dôme de sel : coince le pétrole sous une couche saline. - Piège récifal : coince le pétrole sous un récif.

CONT: There are only four basic kinds of stratigraphic traps: unconformities, porosity permeability pinchouts, reefs, and drape structures. ... Reef Traps. Reefs are productive in many parts of the world. Many types exist, such as atolls, table reefs, pinnacle reefs, barrier reefs, fringing reefs, biostromes, and bioherms. They occur as small dome like features that may be reflected in the overlying sediments by drape. ... The size of a reef ranges from a few acres to several square miles. Seismic exploration is the best way to find reefs. The reef core grows upward and usually outward as the sea level rises. Detrital reef material falls on the ocean side, forming the fore reef. The back reef is formed on the lagoon or quiet side by deposition of limestone and lime mud ...
CONT: Stratigraphic traps are traps created by the limits of the reservoir rock itself, without any structural control. ... Stratigraphic reef traps are amongst the most important type of trap in Alberta, where reefs of Devonian age, formed mainly of stromatoporoids host much of the petroleum. They became ideal traps when a change in the regional environment caused the reefs to be buried by muds, forming an impermeable seal and cap rock.