THE CHARACTERISTICS OF LOWER SILURIAN SOURCE ROCKS IN GAOJIABIAN FORMATION IN THE LOWER YANGTZE LAND AREA

Upon the request of the field excursion to the Yangtze region in 2015, previous research data and references as well as latest drilling wells are collected. The Gaojiabian Formation of Lower Silurian is considered as the deposits of the continental shelf facies, with a wider range of hydrocarbon source rocks in large thickness in the Lower Yangtze area. A great number of graptolite is discovered, indicating a great potential of hydrocarbon generation, in particular the bottom layers. The outcrop of the Gaojiabian Formation is mainly yellow-green in color, but becomes darker with depth. It is speculated that the source rock would be black if it was not weathered. The original organic matter abundance is high with moderate maturity. It is considered as a set of hydrocarbon source rocks with high potential. The Gaojiabian Formation suffered from weaker tectonic deformation and there are better combinations of source rock, reservoir and cap rock. So it is good for formation and preservation of conventional oil and gas and shale gas.