Abstract:

Marine carbonate rocks in South China cover an area of 200?10⁴ km².From Upper Sinian to Lower Triassic,the total thickness of source rocks is up to several thousand me-ters with rich organic matter.But preservative condition underwent serious damage as in-tensive tectonic movements took place in Indo-China period.As faults and denuda-tion caused surface water to distroy reservoir,thus favourable preservation region must be the one that has fine covery rocks in vertical and good sealing hydrogeological condition in horizontal.The Middle Triassic-Jurassic,Silurian,Lower Cambrian in the study area are perfect regional covery rocks which may seal gas reservoir with more than 500m high gas column.There are three kinds of preservation area:1.Paloozoic bare zone;2.Meso-Cenozoic covering zone;3.The frontal zone of nappe structure.