Recent analysis of marine carbonate oil and gas fields in Tarim Basin

Sichuan Basin and Erdos Basin reveals that carbonate traps and reservoirs in China can be classified into 4 major categories (i.e.structural traps

lithologic traps

stratigraphic traps and hybrid traps) and 21 types.The paper focuses on only stratigraphic and lithologic traps as they are more common trap types in the country.The lithologic traps can be further classified into bioherm traps

grain bank traps and diagenetic traps.The stratigraphic traps can also be classified into fault-block buried hill traps

peneplain erosion paeleogeomorphologic traps

monadnock buried hill fracture-vuggy traps

quasi-bedded fracture-vuggy traps

stratigraphic wedge traps and stratigraphic onlap pinchout traps.The paper points out that the marine carbonate oil and gas fields on China mainland are mainly of stratigraphic and lithologic reservoirs with moderate to low abundance.The bioherm reservoirs and grain bank reservoirs develop and distribute in a bead-like shape along platform margin

while the peneplain erosion palaeogeomorphologic reservoirs present as the shape of crumbs;the fractured-vuggy reservoirs are distri-buted widely in the quasi0bedded shape.The large ancient uplift

slope zone and platform margin

are considered favorable areas for cluster distribution of lithologic and stratigraphic oil and gas reservoirs and therefore are regarded to have great potential for hydrocarbon exploration.