EVALUATION ON EXCELLENT MARINE HYDROCARBON SOURCE LAYERS IN SOUTHEAST AREA OF THE SICHUAN BASIN——AN EXAMPLE FROM WELL D-1

The synthetical organic geochemistry section was established by the data of TOC,chloroform bituminous "A",and hydrocarbon generation potential of the drilled marine sequences of Well D-1 in the southeast area of the Sichuan Basin.Synthetical analysis based on the organic geochemistry section of Well D-1,combining with regional geological information indicated that there were three sets of excellent marine source rocks developed in the area,i.e.the black mudstones and black marls of the Upper Permian Longtan Formation,black mudstones of the Lower Silurian bottom Longmaxi Formation and black mudstones of the Lower Cambrian bottom Niutitang Formation.The bituminous algal dolostone of the Sinian Dengying Formation and the bioclastic-limestone of the Permian Qixia Formation was believed to be good secondary hydrocarbon generation source because of their high solid bitumen and chloroform bituminous "A" contents.Furthermore,the mudstones of the middle Longmaxi Formation were the good source rocks.Muddy limestone of the lower Siniulan Formation and lime-mudstones of upper Longmaxi Formation were medium source rocks.Existence of many sets of excellent hydrocarbon source rocks and good secondary hydrocarbon generation source can supply abundant matters for the hyrocarbon accumulation in this area.