基于瞬态压力脉冲法的含水合物沉积物渗透性实验研究

Experimental investigation on permeability of hydrate bearing sediments based on pressure pulse method

水合物藏的渗透特性是判断工业开采可行性的重要参数。为了研究以粉细砂为主构成的多孔介质中水合物对其渗透率的影响，基于瞬态压力脉冲法的原理及求解方法，研制了一套适用于测量含水合物沉积物渗透率的实验装置。利用该装置对含不同饱和度二氧化碳水合物的粉细砂样品进行了渗透率测量实验。结果表明，随着粉细砂样品中二氧化碳水合物饱和度的增加，其渗透率呈指数衰减趋势；将实验数据与渗透率模型进行对比，发现实验数据与水合物占据毛细管中心的平行毛细管模型最为相近。据此推断，水合物在细砂样品中的赋存状态以悬浮模式或接触模式为主。

The permeability of hydrate reservoirs is an important parameter to judge the feasibility of industrial exploitation. In order to study the effect of hydrate in porous media composed mainly of silty-fine sands on its permeability, based on principle of pressure pulse method, an experimental device suitable for measuring permeability of hydrate bearing sediment has been developed. Permeability measurement of simulated porous media containing carbon dioxide hydrate with different saturations was carefully carried out by using this device. Results show that the permeability decreases exponentially with the increase of carbon dioxide hydrate saturation in the porous media. Comparing permeability model with the experimental data, it is found that the experimental data are very close to a parallel capillary model, in which, hydrate occupies capillary center. The pore habit of hydrate in sediment is deduced to be floating and contacting.