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

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.