Proper models for predicting strength parameters of reservoirs are vital to the numerical simulation and risk analysis during gas hydrate exploration. However, unlike homogeneous hydrate reservoirs, strength parameters of interlayered sediments depend on hydrate distribution modes, which remains unclear. Herein, a series of triaxial shearing tests on sediments with hydrate layered distribution are conducted to investigate variations of strength parameters and effects of sublayers. The results indicate that failure strength of whole sediments mainly depends on the high hydrate-saturated sublayer, while the cohesion is more relevant to the low hydrate-saturated layer. Besides, prediction models are proposed to estimate the failure strength through data-fitting, strength-average, and hydrate-average methods. By comparing the accuracy and applicability of these three methods, the hydrate-average method is the best way to estimate failure strength for current use. This study can provide a feasibility reference for strength estimation and risk control during natural gas hydrate development.

中文翻译：

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基于三轴剪切试验的水合物层状分布沉积物强度参数估算

正确的储层强度参数预测模型对于天然气水合物勘探过程中的数值模拟和风险分析至关重要。然而，与均质水合物储层不同，层间沉积物的强度参数取决于水合物的分布模式，这一点仍不清楚。本文对水合物层状分布的沉积物进行了一系列三轴剪切试验，以研究强度参数的变化和次层的影响。结果表明，整个沉积物的破坏强度主要取决于高水合物饱和次层，而内聚力与低水合物饱和层关系更大。此外，还提出了预测模型，通过数据拟合、强度平均和水合物平均方法来估计破坏强度。通过比较这三种方法的准确性和适用性，水合物平均法是当前使用的估计破坏强度的最佳方法。该研究可为天然气水合物开发过程中的强度估算和风险控制提供可行性参考。