四川盆地东南部海相层系优质烃源层评价——以丁山1井为例

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

对川东南地区丁山1井钻遇的海相地层的有机碳含量、氯仿沥青"A"、生烃潜量等进行分析,建立了该井的有机地化综合剖面。结合区域地质资料综合分析认为:川东南地区发育了上二叠统龙潭组黑色泥岩及碳质泥岩、下志留统龙马溪组底部黑色泥岩、下寒武统牛蹄塘组底部黑色泥岩3套海相优质烃源岩;震旦系灯影组含沥青藻云岩和二叠系栖霞组生屑灰岩中固体沥青和氯仿沥青"A"含量高,为好的再生烃源;龙马溪组中部灰色泥岩为一套好的烃源岩;志留系石牛栏组底部泥灰岩和龙马溪组顶部灰质泥岩为中等烃源岩。川东南地区多套优质烃源岩及再生烃源的存在,为该区的油气勘探提供了丰富的物质基础。

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 bi tuminous ＂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.