THE DISTRIBUTED CHARACTERISITIC OF MIDDLE JURASSIC BUQU FORMATION CARBONATE SOURCE ROCK IN MIDWEST AREA OF NORTH QIANGTANG DEPRESSION

According to the typical section measured and the auxiliary correlation section observation,as well as massive system samples data analysis,we thought that the Middle Jurassic Buqu Formation in the North Qiangtang Depression is mainly composed of a set of thickness huge semi-restricted lagoon facies micrite,marl and the tidal flat grain limestone,the gypsolith,the mudstone and so on.The carbonate source rocks mainly is the lagoon facies dark color micrite and the marl.The source bed in on longitudinal mainly delivers its lower segment and the upside;on crosswise from the depression interior to the depression edge,source rock thickness attenuates gradually and the organic carbon content variations characteristic.The source bed distribution characteristic of the Buqu Formation is controlled by the sedimentary facies and the sea level fluctuation change obviously.Its distributed characteristic have the vital significance to appraise uncooked oil prospect and seek the main uncooked oil depression.