合肥盆地盆缘刘老碑组烃源岩特征探讨

依据刘老碑组在合肥盆地周围的露头和钻井资料,通过地层特征、有机地化指标和岩相古地理的综合分析,认为刘老碑组有机质丰度达到烃源岩的要求,母质类型为Ι型干酪根,烃类转化率高,而且泥岩厚度大,总生烃量也大;虽然有机质已经过成熟,但完全可以生气,即处于热裂解成凝析油-湿气阶段,因此提出刘老碑组可作为合肥盆地的气源岩。此外,依据地层和盆地内的地球物理资料,推测合肥盆地内部可能存在刘老碑组,这为合肥盆地寻找天然气藏提供了理论依据。 

DISCUSSION ON THE HYDROCARBON SOURCE ROCK CHARACTERS OF THE LIULAOBEI FORMATION ON THE FRINGES OF THE HEFEI BASIN

Based on the data of outcrops and wells on the fringes of the Hefei Basin and the synthetical analyses of stratigraphic characters, organic geochemical indexes and lithofacies paleogeography, the authors believed that the organic abundance of the Liulaobei Formation reached the standard of hydrocarbon source rocks. Its matrix type was Ⅰ-type kerogen, it mudstone was thick, its hydrocarbon percent conversion was high, and its hydrocarbon productive amount was great. Though the organic material of the Liulaobei Formation was overmature, it can still split into condensate oil and humid gas. So, it was suggested that the Liulaobei Formation can be considered as the gas source rock of the Hefei Basin. Besides, based on the stratigraphic and geophysical data, it was inferred that the Liulaobei Formation was existing in the inner of the Hefei Basin. These conclusions provided theoretical bases for exploring gas pools in the Hefei Basin.