Evaluation of the effect of geothermal water flooding on offshore marine sandstone thin heavy oil reservoir
The geothermal water flooding in thin heavy oil reservoirs with edge water in eastern South China Sea has shown a good development result,but the enhanced oil recovery(EOR)mechanisms and development effect of geothermal water flooding have not been re-vealed.In this paper,we considered heavy oil thermal recovery,simulation of the heat loss to surrounding rock and field practice to study the heavy oil EOR mechanisms and effect from geothermal water flooding.The results showed that geothermal water flooding can significant-ly reduce the viscosity of crude oil,the residual oil saturation can be reduced by 7.24%～8.22%and the oil displacement efficiency can be increased by 8.85%～9.11%.In the early stage of geothermal water flooding,heat exchange occurs between the waterflood front and the surrounding strata,and the temperature decreases rapidly,the influenced range of geothermal water flooding is 50～150 m.The recovery method is to use low speed uniform water flooding to maintain pressure and to produce oil.In the later stage,the oil recovery of geothermal water flooding can be improved by increasing temperature sweep area with higher injection rate.After the injection of geothermal water in E oil reservoir,the production of oil well increases rapidly,and the water injection well water absorption index increases gradual-ly due to the decrease of the near-well viscosity and the increase of the water phase per-meability.With the improvement of injection-production well pattern,the reservoir pressure coefficient increases year by year,and the oil production continues to increase.The predict-ed recovery rate is 40.0%,and the enhanced recovery rate of geothermal water flooding reaches 4.8%.
marine sandstoneheavy oilgeothermal water floodingheat lossoil recovery
万方数据
维普
