Research progress on thermal-fluid coupling and temperature field regulation in natural gas hydrate production tests in the South China Sea
Gas hydrate reservoirs in the South China Sea are mainly composed of clayey silts,presenting exploitation challenges compared to sandy reservoirs.This paper summarizes recent research by our team,focusing on the evolution of phase change behaviors,effective permeability changes,heat flux coupling mode,temperature field regulation within the trial production system,and mine-scale warming and anti-icing involved in the depressurization mining of clayey silt gas hydrates in the northern South China Sea.The results show that the phase transitions in clayey silt hydrate are consistently in dynamic equilibrium,exhibiting a pronounced hysteresis effect due to the high clay content.The throttling expansion effect is strong at the test production wall,resulting in the steepest"temperature funnel"slope.Once a"water lock"forms and secondary hydrate generation occurs,gas-phase seepage capacity significantly decreases.In the absence of external heat source recharge,high initial gas production rates can hinder hydrate decomposition,potentially leading to cessation of decomposition.The decomposition of clayey silt gas hydrates in the South China Sea is mainly affected by heat transfer control mode.Therefore,developing an efficient"reservoir-wellbore"trial production system with multiple temperature and pressure regulation methods and robust flow mechanisms is crucial to improving gas production efficiency.Relying on the Qinghai multi-natural gas hydrate and permafrost environment field scientific observation and research station of the Ministry of Natural Resources,the in-situ heating and pressure reduction filling method was used to successfully complete the temperature field transformation test of a mine-scale hydrate trial production system.This further optimized and improved the seepage capacity of the reservoir and realized the purpose of increasing permeability and expanding production.
clayey siltstest mining systemphase change habitsthermal-fluid couplingtemperature field regulation
万方数据
维普
