压缩加载条件下含水合物沉积物蠕变特性分析

Analysis of creep characteristics of hydrate sediments under compressive loading

  • 摘要: 水合物开采可能诱发海底滑坡或其他工程地质灾害。实现水合物商业化开采需要中长期稳定产气,长期荷载下储层的蠕变特性是地层稳定性评价的基础力学参数。利用南海水合物储层粉黏土为试验介质在压缩加载条件下的系列固结排水蠕变测量试验结果,对粉黏土的蠕变特性进行了分析。结果表明,加载过程中,含水合物沉积物经历瞬时变形、固结变形和蠕变变形3个阶段;随着加载应力和水合物饱和度的提高,蠕变应变不断增加;修正的Singh-Mitchell蠕变模型可以较好预测不同应力水平和水合物饱和度下粉黏土的蠕变特性。

     

    Abstract: Hydrate mining may induce submarine landslides or other engineering geological disasters. Long-term and stable gas production is required for any commercial exploitation for natural gas hydrate. Understanding the creep properties of hydrate-bearing sediments is importance for the estimation of long-term stratum instability. Therefore, we analyzed the creep characteristics of silty clay by using a serial test on consolidation drainage creep under compression loading conditions with hydrate reservoir silty clay as the test medium. The results show that the deformation curves of hydrate bearing sediments presented three stages: instantaneous deformation, consolidation deformation, and creep deformation. With the increase of load and hydrate saturation, the creep strain increased progressively. The modified Singh-Mitchell creep model was applied, by which the creep properties of hydrate bearing sediments were well predicted at different stress levels and hydrate saturations.

     

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