南海琼东南盆地-西沙海槽天然气水合物地球化学勘探与资源远景评价

研究工区范围为南海琼东南盆地至西沙海槽一线的海域。数据来自：中国地质大学参加了2000年和2006年在中国南海西沙海槽工区天然气水合物地球化学勘探，通过现场快速勘查实测和室内分析测试得到的多种烃类数据；申请到大洋钻探3个航次典型钻井的样品，经国内实验室实测得到的酸解烃指标和酸解烃微量甲烷碳同位素数据；搜集的其他文献涉及研究区的酸解烃指标数据和酸解烃微量甲烷碳同位素数据。依据甲烷的地球化学特征、湿度比值分布和甲烷碳同位素的组成特征对研究区天然气水合物的成因进行了分析研究；依据数据对比探讨了酸解烃微量甲烷同位素值的地球化学意义,对中国海区天然气水合物的成因进行了讨论判别。最后，依据上述结论对区内天然气水合物资源的远景进行了评价和预测。

Geochemical prospecting of natural gas hydrate and resource evaluation in Qiongdongnan basin-Xisha trough of South China Sea

Main working area of this paper is part of ocean from Qiongdongnan Basin to Xisha Trough in South China Sea. The data in this paper consisted: the data collected in the marine science investigation about gas hydrate in Qiongdongnan Basin and Xisha Trough from 2000 to 2006; the data from tested samples applied from ODP164、ODP204 and ODP308 where had found gas hydrate, which were tested for hydrocarbon compositions and acidolysis hydrocarbon isotopic compositions in laboratory; the data gathered from others papers. On the basis of analysis of distribution characteristics of methane, C1/(C2+C3) and characteristics of hydrocarbon isotopic compositions, we analyzed the cause of gas hydrate and the geochemical significance of acidolysis hydrocarbon isotopic compositions. Combined geochemical data with geological data, the best block for gas hydrate bearing was selected and the occurrence of gas hydrate in the working area was prospected.