EXPERIMENTAL STUDY ON CO2 REPLACEMENT-EXPLOITATION OF NATURAL GAS HYDRATE UNDER TRIAXIAL STRESS
In order to simulate the real environment in the sea area,these experiments were carried out to study the effects of sodium chloride,initial saturation of the reservoir and replacement compressive stress on the liquid CO2 replacement-exploitation of natural gas hydrate in the sea area under the rich water condition.This study shows that under the condition of triaxial stress and porosity about 46.70%,the sodium chloride system has little effect on the CH4 replacement efficiency,but it inhibits the CO2 hydrate synthesis.There is a negative correlation between initial reservoir saturation and CH4 replacement efficiency.In addition,a high reservoir water content is more favorable for CO2 storage.The CH4 replacement efficiency increases with the increasing replacement compressive stress,the increase of replacement compressive stress provides a high driving force for the CO2 hydrate formation,thereby improving the CO2 sequestration efficiency.
natural gas hydratecarbon dioxidemethanesodium chloridereplacementtriaxial stressinitial reservoir saturation