“Uniform geothermal gradient” and heat flow in the Qiongdongnan and Pearl River Mouth Basins of the South China Sea
“Uniform geothermal gradient” and heat flow in the Qiongdongnan and Pearl River Mouth Basins of the South China Sea
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DOI：
10.1016/j.marpetgeo.2008.08.008
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发表时间：
2009-08
影响因子：
4.2
通讯作者：
Yuan Yusong;Weilin Zhu;Lijun Mi;Gongcheng Zhang;Shengbiao Hu;Lijuan He
中科院分区：
文献类型：
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作者：
Yuan Yusong;Weilin Zhu;Lijun Mi;Gongcheng Zhang;Shengbiao Hu;Lijuan He
珠江口盆地和琼东南盆地是南海北方边缘的含油气盆地。地质测量是石油勘探的重要手段。一个大的数据集，包括199热导率，40放射性产热，543实测地热梯度值，和224热流值已从两个盆地。然而，测量的地热梯度数据来源于不同的深度范围，使空间比较成为一项具有挑战性的任务。考虑到岩石电导率和产热率的变化，我们用“均匀地温梯度”来描述PRMB和QDNB的地温梯度分布。结果表明，在0- 5 km深度范围内，青藏高原的“均匀地温梯度”为17.8 ~ 50.2°C/km，平均为32.1±6.0°C/km。相比之下，QDNB的平均“均匀地热梯度”为31.9±5.6°C/km，范围在19.7°C/km和39.5°C/km之间。PRMB和QDNB的热流分别为71.3±13.5mW/m2和72.9±14.2mW/m2。由于新生代岩石圈/地壳减薄，从大陆架到陆坡，PRMB和QDNB的热流和地温梯度有增加的趋势。
The Pearl River Mouth Basin (PRMB) and Qiongdongnan Basin (QDNB) are oil and gas bearing basins in the northern margin of the South China Sea (SCS). Geothermal survey is an important tool in petroleum exploration. A large data set comprised of 199 thermal conductivities, 40 radioactive heat productions, 543 measured geothermal gradient values, and 224 heat flow values has been obtained from the two basins. However, the measured geothermal gradient data originated from diverse depth range make spatial comparison a challenging task. Taking into account the variation of conductivity and heat production of rocks, we use a “uniform geothermal gradient” to characterize the geothermal gradient distribution of the PRMB and QDNB. Results show that, in the depth interval of 0–5km, the “uniform geothermal gradient” in the PRMB varies from 17.8°C/km to 50.2°C/km, with an average of 32.1±6.0°C/km. In comparison, the QDNB has an average “uniform geothermal gradient” of 31.9±5.6°C/km and a range between 19.7°C/km and 39.5°C/km. Heat flows in the PRMB and QDNB are 71.3±13.5mW/m2and 72.9±14.2mW/m2, respectively. The heat flow and geothermal gradient of the PRMB and QDNB tend to increase from the continental shelf to continental slope owing to the lithosphereic/crustal thinning in the Cenozoic.