Experimental study of sand control in a natural gas hydrate reservoir in the South China sea

Abstract

Gas hydrate is considered to be one of the most promising energy sources of the 21st century, however, with the deepening of research on hydrate resources and the acceleration of trial exploitation processes, it has become apparent that sand production is one of the key factors restricting hydrate exploitation. Here we focus on the key issues of sand production in natural gas hydrate reservoirs in the Liwan Sea area in the northern part of the South China Sea. Innovative systematic studies of the mode of hydrate sand production using a multi-channel hydration acoustic wave monitoring system were conducted. The results show that a hydrate formation composed of very fine silt is prone to excessive sand production requirement. When the production pressure difference is only 1 MPa, the sand output already accounts for 19% of total liquid production, making sand production an important issue under these conditions. Finally, using filter screens with different pore sizes, hydrate reservoir sand control simulations were carried out. The results were analysed to determine properties such as: sand yield, permeability, sand content, and productivity. The design criterion for the filter screen of the fine sand particles in hydrate formations was finally obtained as D50 = 11d50 (where D50 is median grain size of the gravel, and d50 is the median grain size of the formation).