Study on the Influence of Sand Production on Seepage Capacity in Natural Gas Hydrate Reservoirs

Abstract

Sand production has become a common phenomenon in the exploitation of unconsolidated natural gas hydrate reservoirs, which will hinder the long-term production of natural gas hydrate reservoirs. However, there are few literatures reported on the influences in reservoir physical properties such as permeability and porosity, and production laws caused by sand production. This paper provides a numerical model, coupled with reservoir sand-gas-water multiphase flow processes, which is capable to simulate the process of sand production in natural gas hydrate reservoirs. The simulation results indicate that sand settlement is mainly concentrated near the wellbore due to the high concentration of migrated sand. The decrease in reservoir porosity and permeability caused by sand settlement has a significant impact on production. The impact of sand production on reservoir fluid fluidity shows that fluid flow is inhibited near the wellbore, while fluid flow performance increases far away from the wellbore. The numerical model and analysis presented here could provide useful insight into changes in reservoir physical properties and production laws caused by sand production in the natural gas hydrate-bearing marine sediments using depressurization method.

An Interface Parametric Evaluation on Wellbore Integrity during Natural Gas Hydrate Production

“…The reduction in reservoir porosity and permeability caused by sand settlement has a significant impact on production. The effect of sand production on reservoir fluid mobility shows that fluid flow near the wellbore is inhibited, while fluid flow performance is improved farther away from the wellbore [134]. Jiping Ding et al, by introducing the plastic-softening-stage, established a thermal-fluid-solid coupling mathematical model of sand production based on the destruction of reservoir skeleton and hydrate transformation, which truly simulated the sand production process under wellhead pressure reduction and analyzed the sand production mechanism and change rule from the perspective of rock mechanics.…”