瞬态压力脉冲法及其在松散含水合物沉积物中的应用

PRESSURE PULSE-DECAY METHOD AND ITS APPLICATION TO PERMEABILITY MEASUREMENT OF HYDRATE-BEARING SEDIMENTS

  • 摘要: 含水合物沉积物渗透率是水合物开采相关工作的基础参数之一。稳态法在应用于渗透率较低的多孔介质时存在着稳定渗流难和试验耗时长等缺点。目前,含水合物细颗粒沉积物渗透率试验数据积累明显不足。本文首先介绍了瞬态压力脉冲法的基本原理及数据处理方法,然后以模拟试验验证了瞬态压力脉冲法的适用性,最后探讨了该方法在松散含水合物沉积物渗透率测量方面的应用效果。结果表明:瞬态压力脉冲法近似解处理粉细砂沉积物试验数据效果较好,而处理黏土沉积物试验数据存在明显误差,建议采用数值模拟反演分析的方法处理瞬态压力脉冲法试验数据;瞬态压力脉冲法适用于松散沉积物渗透率测量,在含水合物沉积物渗透率试验研究方面具有潜在的应用前景。

     

    Abstract: The permeability of hydrate-bearing sediments is one of the basic parameters to natural gas hydrate exploitation. Steady methods for measuring the permeability are time-consuming and require a steady seepage which is usually difficult to achieve. It is clear that there is a lack of experimental permeability data for fine-grained sediments that contain gas hydrate. To meet the needs of the kind, the pressure pulse decay method and its data processing are firstly introduced in this paper. Then we discussed the application of the method to hydrate-bearing sediments based on calculated data. It is concluded that the approximate solution to experimental data gives good results to coarse-grained sediments, but has some deviations when it is used for fine-grained sediments. In this regard, parametric inversion is suggested. To sum up, the transient pressure pulse decay method is feasible to permeability measurements of unconsolidated sediments, and has a vast potential for future development.

     

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