The BZ19-6 gas field is characterized by high temperature and high pressure (HTHP), high condensate content, little difference between the formation pressure and dew point pressure, and large amount of reverse condens...The BZ19-6 gas field is characterized by high temperature and high pressure (HTHP), high condensate content, little difference between the formation pressure and dew point pressure, and large amount of reverse condensate liquid. During the early stage of depletion development, the production gas-oil ratio (GOR) and production capacity remain relatively stable, which is inconsistent with the conventional reverse condensate seepage law. In view of the static and dynamic conflict in development and production, indoor high-temperature and high-pressure PVT experiment was carried out to reveal the mist-like condensation phenomenon of fluids in the BZ19-6 formation. And the seepage characteristics of condensate gas reservoirs with various degrees of depletion under the condition of HTHP were analyzed based on production performance. The change rule of fluid phase state was analyzed in response to the characterization difficulties of the seepage mechanism. The fluid state was described using the miscible mechanism. And the interphase permeability interpolation coefficient was introduced based on interfacial tension. By doing so, the accurate characterization of the “single-phase flow of condensate gas-near-miscible mist-like quasi single-phase flow-oil-gas two-phase flow” during the development process was achieved. Then the accurate fitting of key indicators for oilfield development was completed, and the distribution law of formation pressure and the law of condensate oil precipitation under different reservoir conditions are obtained. Based on research results, the regulation strategy of variable flow rate production was developed. Currently, the work system has been optimized for 11 wells, achieving a “zero increase” in the GOS of the gas field and an annual oil increase of 22,000 cubic meters.展开更多
Aiming at the large error in productivity predication and incomplete consideration in completion parameters design of perforated horizontalwell,a model which coupled the relationship of pressure and flow rate in reser...Aiming at the large error in productivity predication and incomplete consideration in completion parameters design of perforated horizontalwell,a model which coupled the relationship of pressure and flow rate in reservoir seepage,near-wellbore inflow and wellbore flow was established.The impact of near-wellbore heterogeneity,wellbore flow pressure drop and completion parameters on the inflow profile of horizontalwell is analysed.Studies showed that with a stronger near-wellbore heterogeneity,the inflowprofilewouldfluctuatemore seriously.Perforationdensityhada great influence onthe inflow profile and local changes of it would bring a shunt effect.Completion design of variable density perforated horizontalwell with an optimized inflowprofile whichwas close to a standard profilewould improve the horizontal well development effect.The achievement can provide directive meanings to productivity predication and completion parameters design of horizontal wells in oilfield.展开更多
文摘The BZ19-6 gas field is characterized by high temperature and high pressure (HTHP), high condensate content, little difference between the formation pressure and dew point pressure, and large amount of reverse condensate liquid. During the early stage of depletion development, the production gas-oil ratio (GOR) and production capacity remain relatively stable, which is inconsistent with the conventional reverse condensate seepage law. In view of the static and dynamic conflict in development and production, indoor high-temperature and high-pressure PVT experiment was carried out to reveal the mist-like condensation phenomenon of fluids in the BZ19-6 formation. And the seepage characteristics of condensate gas reservoirs with various degrees of depletion under the condition of HTHP were analyzed based on production performance. The change rule of fluid phase state was analyzed in response to the characterization difficulties of the seepage mechanism. The fluid state was described using the miscible mechanism. And the interphase permeability interpolation coefficient was introduced based on interfacial tension. By doing so, the accurate characterization of the “single-phase flow of condensate gas-near-miscible mist-like quasi single-phase flow-oil-gas two-phase flow” during the development process was achieved. Then the accurate fitting of key indicators for oilfield development was completed, and the distribution law of formation pressure and the law of condensate oil precipitation under different reservoir conditions are obtained. Based on research results, the regulation strategy of variable flow rate production was developed. Currently, the work system has been optimized for 11 wells, achieving a “zero increase” in the GOS of the gas field and an annual oil increase of 22,000 cubic meters.
文摘Aiming at the large error in productivity predication and incomplete consideration in completion parameters design of perforated horizontalwell,a model which coupled the relationship of pressure and flow rate in reservoir seepage,near-wellbore inflow and wellbore flow was established.The impact of near-wellbore heterogeneity,wellbore flow pressure drop and completion parameters on the inflow profile of horizontalwell is analysed.Studies showed that with a stronger near-wellbore heterogeneity,the inflowprofilewouldfluctuatemore seriously.Perforationdensityhada great influence onthe inflow profile and local changes of it would bring a shunt effect.Completion design of variable density perforated horizontalwell with an optimized inflowprofile whichwas close to a standard profilewould improve the horizontal well development effect.The achievement can provide directive meanings to productivity predication and completion parameters design of horizontal wells in oilfield.
