资福寺洼陷烃源岩分布及生烃潜力评价

利用地震、钻井、测井和油气地球化学分析测试资料,分析资福寺洼陷烃源岩分布特征,结合埋藏史分析烃源岩的成熟史与生烃演化史,对烃源岩的生烃潜力进行动态评价。烃源岩主要分布于湖相-半深湖相区,近北西-南东向展布,向北东、南西两侧减薄,其中新沟咀组下段Ⅱ油组和沙市组上段厚度较大。有机碳含量高值区主要分布在弥陀寺-资福寺一带,新沟咀组下段泥隔层和Ⅱ油组有机碳含量较高,达到1.0%。综合考虑烃源岩分布特征及生烃演化史,有利生烃层位以新沟咀组下段Ⅱ油组为主,有利生烃区位于资福寺洼陷带。

The Distribution of Source Rock and Hydrocarbon Generation Potential Analysis in Zifusi Depression

Zifusi Sag,which was located in the southeast of Jiangling Depression,was a Cenozoic depression grown up on the Mesozoic basement.It was a tectonic framework where depression was alternated with uplift.The main source rock was the in the Lower Xingouzui Formation and Shashi Formation.TypeⅡ Oil Formation had higher organic matter abundance,its organic matter was mainly TypeⅡ2-Ⅲ.Thermal maturation degree was at maturated to highly maturated stage.The distribution characteristics of source rocks were analyzed by seismic,drilling,logging and oil and gas geochemical test data,and mature history and hydrocarbon-generation evolvement history were obtained in combination with burial history,hydrocarbon potential was dynamically evaluated.Source rocks are almost distributed in lacustrine facies to half deep lacustrine facies,which is developed from northwest to southeast,and it is thinned in northeastern and southwestern side.TypeⅡ Oil Formation and Upper Shashi Formation are relatively thick.Source rock area with higher organic carbon content is located in the Mituosi-Zifusi Area.The TOC content of restraining barrier and TypeⅡOil Formation of the Lower Xingouzui Formaion is much higher,which is at 1.0%.In consideration of the distribution of source rocks and hydrocarbon evolution,the favorable hydrocarbon layer is TypeⅡOil Formation of the Lower Xingouzui Formation,and the favorable hydrocarbon area is Zifusi Depression.