Session: 11-10-04 Development of Unconventional Reservoirs-4

Paper Number: 79775

79775 - Pore-Scale Investigation on Dynamic Permeability Characterization of Hydrate-Bearing Sediments 

Natural gas hydrates which are widely distributed in marine sediments and permafrost have attracted global attentions as great potential energy resources. The permeability is an essential and important parameter that critically affects the rate and efficiency of gas production from hydrate-bearing sediments. Reported permeability values are observed to be widely scattered due to multiple influencing factors such as hydrate saturation, hydrate pore habit and so on, bringing a great challenge for accurate representation. Although a large number of studies on permeability prediction of natural gas hydrates have been conducted, the parameters in the predictive model are always needed to be determined in advance. In this study, an unstructured hydrate-bearing network model with anisotropic is firstly constructed. Afterwards, a pore scale flow network model considering preferential hydrate pore clogging habits and hydrate dissolution is developed. Based on the established flow network model, dynamic permeability evolution during hydrate dissolution is investigated under different hydrate saturations, pore connectivity and pore size distribution conditions. The results show a decrease in the permeability for an increase in the hydrate saturation, a decrease in pore connectivity and pore size. Furthermore, a novel mathematical permeability prediction model of hydrate-bearing sediments is proposed. The mathematical model is more accurate in permeability prediction of hydrate-bearing sediments compared with other existing models. This study provides a systematic theoretical analysis for dynamic flow properties in hydrate-bearing sediments, which lays a good foundation for high efficiency of natural gas hydrate production.

Presenting Author: Mingqiang Chen Research Center of China National Offshore Oil Corporation

Authors:

Mingqiang Chen Research Center of China National Offshore Oil Corporation
Qingping Li Research Center of China National Offshore Oil Corporation
Xin Lyu Research Center of China National Offshore Oil Corporation
Qi Fan Research Center of China National Offshore Oil Corporation
Yang Ge Research Center of China National Offshore Oil Corporation
Chaohui Lyu China University of Petroleum(Beijing)