Failure And Injection Of Gas Condensate In Porous Media Development Mechanism

Gas condensate fields are parts and parcels in the development of the gas field in China, the development of the gas condensate fields are lay store by the petroleum industry. Gas condensate fields are kinds of exceptive and complicated gas field; they assume key economic value because they both produce natural gas and condensate oil; the appearance of retrograde condensation because of the declining of the formation pressure during the development of those fields can make the development of this fields difficult, and because of it ,it is difficulty to improve the percent recovery of condensate oil.The conventional development fashions for the gas condensate fields are natural depletion and cyclic gas injection. Although a good deal of condensate oil is loss in the formation because of the appearance of retrograde condensation by the method of natural depletion, it is the main development method in China because of the lower investment cost. This paper closely researches the natural depletion mechanism for gas condensate fields and the factors affecting the effictiveness of developing the gas condensate fields by natural depletion with the help of the core experiments of Talimu ZhongYuan and DaGang; tests the critical flow saturation of condensate oil during the period of the depletion, the percent recovery of condensate oil and gas, the real relative permeability curves of equilibrium condensate oil and gas in porous medium . The results show that the real relative permeability curves are more different than the conventional ones, this paper thinks the IFT is the main reason leading the difference ; with two types of relative permeability curves, simulates and forecasts the results of experiments by CMG.. The research shows that the percent recovery of natural gas and condensate oil in core experiments are larger than one in PVT experiments; the forecasted percent recovery of condensate oil in depletion with the new relative permeability curves is more close to the result of depletion experiments in the real cores.This paper first conducts indoor waterflooding gas condensate system experiments in China, approaches the feasibility of waterflooding gas condensate from the aspects of the mechanism, experiment . The cores and the fluids in experiments are from the BanQiao abandoned gas condensate reservoirs. This paper conducts PVT analysis on the fluids and conducts different pressure and speeds waterflooding experiments. The research shows that different pressure, speeds and quantity of water injection can lead to different percent recover}'; water injection in abandoned gas condensate reservoirs can yield higher the percent recovery of natural gas and condensate oil than those in the natural depletion.