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保山盆地是云南第三系沉积盆地的典型代表，面积２４５ｋｍ２。烃源岩的发育与成熟度是这类盆地油气远景的重要控制因素。保山盆地母岩含有一定的有机质，泥岩有机碳含量在１０％～２０％之间，以上第三系上新统羊邑组二段有机碳含量最高，有机质丰度与岩性关系密切，不同的有机质丰度指标对烃源岩级别的反映有差异；岩石热解结果、干酪根的性质、生物标志化合物组成分布特征等反映出的有机质类型是以腐泥腐殖型和腐殖型为主，处于未成熟和低成熟阶段；保山盆地半深湖—深湖相主要发育于盆地中部坳陷带，这是该盆地主力烃源岩的分布范围；现今处于１４００ｍ之下的半深湖—深湖相的范围是保山盆地成熟烃源岩的范围；保山盆地天然气以生物气为主，具有产生生物气（细菌气）的优越条件。在保山盆地也可能找到生物—热催化过渡带气。

HYDROCARBON SOURCE ROCKS AND THEIR NATURAL GAS GENERATION CHARACTERISTICS IN BAOSHAN BASIN,YUNNAN PROVINCE

Baoshan Basin is a typical representative of the Tertiary sedimentary basins in Yunnan Province,being of an area of 245 km 2.The growth and maturity of hydrocarbon source rocks are the important control factors of evaluating the oil and gas prospects in such kind of basin.The source rocks in Baoshan Basin contain a certain of organic matter and the organic carbon content in mudstone changes from one percent to two percent,being the most in the second member of Yangyi Formation of Pliocene,Neogene.The organic matter abundance is closely related to lithology and the reflection of various organic matter abundance indexes on hydrocarbon source rock rank is different.According to the result of rock pyrolysis,the property of kerogen and the distribution characteristics of biomarker composition,the organic matters are mainly saprohumic and humic types,being in immature and low mature stages.The semideep deep lacustrine facies in Baoshan Basin is mainly developed in the depression in the central part of the basin,being the distribution scope of the major hydrocarbon source rocks in the basin.The scope of the semideep deep lacustrine facies sitting in the depth of below1 400 m at present is that of the maturation hydrocarbon source rocks.The natural gas is mainly biogas in Baoshan Basin where there is the favourable conditions of generating biogas(bacterial gas)and the bio thermocatalysis intermediate zone gas will be found also.