南海北部琼东南盆地岩石热物性特征

岩石热物性是盆地模拟和预测深部温度时不可或缺的参数。琼东南盆地是当前我国海洋油气资源勘探开发的重点区块，揭示该盆地的热状态和烃源岩热演化历史均离不开真实可靠的岩石热物性参数。前人虽然对南海北部地区的岩石热物性开展过相关研究，仍存在实测数据偏少、代表性不足和相互矛盾等问题，亟需新增一批新的实测数据来弥补该区基础地热参数的不足。文章对采自琼东南盆地19口钻孔的32块岩心样品开展了热导率、生热率以及密度和孔隙度等物性参数测试，揭示了它们的空间展布特征、相互关系及其主控因素，建立了琼东南盆地新生界地层平均热导率和生热率，据此估算出盆地沉积物的放射性生热贡献约占地表热流的33%。这些实测的岩石热物性参数为南海北部海域沉积盆地的盆地模拟和地热相关研究提供了坚实的基础数据。

Thermal Properties Characterization of the Rocks in the Qiongdongnan Basin,Northern Margin of the South China Sea

Data regarding thermal properties of sedimentary rocks are fundamental for basin modelling and deep temperatureprediction of sedimentary basins. The Qiongdongnan Basin, located at the northern margin of the South China Sea, currently is the keyarea of the offshore hydrocarbon exploration in China. Reliable rock thermal properties are necessary for understanding the thermalregime and thermal evolution of source rocks of the Qiongdongnan Basin. Although previous studies of rocks thermal properties havebeen carried out for this area, there still exist such problems as limited measured data, under-representation and even controversies,and it is emergent to retrieve some new measured data to fill this gap. In this study, 32 core samples of 19 boreholes were collected fromthe Qiongdongnan Basin, and a systemic measurement of the thermal properties, i.e., thermal conductivity, radioactive heat production,these thermal properties are presented. Integrating previous thermal properties with our new data, the average thermal conductivity andradioactive heat production of the Cenozoic formation in the Qiongdongnan Basin are established. The radioactive heat contribution ofsediments within the basin account for nearly 33% of observed present-day heat flow. These measured data could provide a benchmarkfor basin modelling and geothermal regime in the sedimentary basins of the northern South China Sea.