据野外露头观察和采样分析,湘中坳陷上古生界碳酸盐岩烃源岩以泥质灰岩、泥灰岩和石灰岩为主,生油母质以偏泥型为主,烃源岩的沉积厚度大、分布范围广,并具有有机碳丰度高、样品达标率高、热演化程度高的"三高"特点.在对碳酸盐岩烃源岩热演化研究的基础上总结出生烃模式,认为本区的生烃分为原始沥青解聚成烃、干酪根降解成烃、包裹有机质释放成烃和热裂解气共四个成烃阶段.

The Lower Paleozoic carbonate source rocks are thick and wide-distributed in Xiangzhong Depression so it is one of potential prospecting areas in southern China. Result of outcrop observation and sample analysis show that the source rocks mainly consist of argillaceous limestone, marl and limestone with high values of TOC and Ro. Organic matter is mainly Type-Ⅰ kerogen. Analysis of thermal evaluation of the source rocks demonstrate a model of hydrocarbon generation as following four stages: asphalt disaggregation(immature-low mature stage), kerogen degradation(mature stage), organic inclusion release(high mature) and thermal prolysis gas(overmaturate stage).