基于ArcGIS工具, 运用证据权模型, 将墨西哥湾已知天然气水合物矿点作为训练区, 估计水深、构造、地貌、渗漏、陆坡盆地构造、海底温度、地温梯度、有机碳分布等证据图层的控矿证据权系数, 并将系数推广到整个墨西哥湾北坡, 实现对该区天然气水合物资源空间分布的估计。证据权数值说明, 天然气水合物的形成和赋存主要与渗漏、地貌和陆坡盆地构造等因素密切相关, 证据权系数分别是6.6250、2.2726和2.0447; 估计结果表明, 已发现的天然气水合物分布在预测的后验概率区间内, 说明证据权模型在天然气水合物潜在资源预测中具有良好的应用效果; 有利的后验概率区间表明, 墨西哥湾北部陆坡赋存丰富的水合物资源, 在德克萨斯—路易斯安那陆坡至密西西比峡谷一带存在寻找天然气水合物资源的潜力地段。
By using the ArcGIS tool and the Weights-of-Evidence-Modeling, the discovered gas hydrate mineral points in the northern Gulf of Mexico are considered as a training area, and estimate the ore-controlling evidence weight coefficients, which include water depth, seabed faults, seabed physiognomy, seep, slope basins, seabed temperature, geothermal gradient, and organic carbon. Then, the coefficients are extended for the whole northern slope in the Gulf of Mexico to estimate the spatial distribution of gas hydrate resources in the area. Evidence weight coefficients show that the hydrate formation and occurrence are closely related to seep, seabed physiognomy and slope basins; and the coefficients are respectively 6.6250, 2.2726 and 2.0447 for seep, seabed physiognomy and slope basins. Prediction results indicate that the discovered gas hydrate mineralization is distributed in the posterior probability sections, which shows the Weights-of-Evidence can be applied to the prediction of gas hydrate resources. Advantaged posterior probabilities show that there are abundant gas hydrate resources in the northern slope Gulf of Mexico, especially in the Texas-Louisiana-Mississippi canyon that is the potential seabed area searching for gas hydrate resources.
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