A reliable multiphase flow simulator is an important tool to improve wellbore integrity and production decision-making.To develop a multiphase flow model with high adaptability and high accuracy,we first build a multi...A reliable multiphase flow simulator is an important tool to improve wellbore integrity and production decision-making.To develop a multiphase flow model with high adaptability and high accuracy,we first build a multiphase flow database with 3561 groups of data and developed a drift closure relationship with stable continuity and high adaptability.Second,a high-order numerical scheme with strong fault capture ability is constructed by effectively combining MUSCL technology,van Albada slope limiter and AUSMV numerical scheme.Finally,the energy equation is coupled into the AUSMV numerical scheme of the drift flow model in the form of finite difference.A transient non-isothermal wellbore multiphase flow model with wide applicability is formed by integrating the three technologies,and the effects of various factors on the calculation accuracy are studied.The accuracy of the simulator is verified by comparing the measurement results with the blowout experiment of a full-scale experimental well.展开更多
As the classical transient flow model cannot simulate the water hammer effect of gas well, a transient flow mathematical model of multiphase flow gas well is established based on the mechanism of water hammer effect a...As the classical transient flow model cannot simulate the water hammer effect of gas well, a transient flow mathematical model of multiphase flow gas well is established based on the mechanism of water hammer effect and the theory of multiphase flow. With this model, the transient flow of gas well can be simulated by segmenting the curved part of tubing and calculating numerical solution with the method of characteristic curve. The results show that the higher the opening coefficient of the valve when closed, the larger the peak value of the wellhead pressure, the more gentle the pressure fluctuation, and the less obvious the pressure mutation area will be. On the premise of not exceeding the maximum shut-in pressure of the tubing, adopting large opening coefficient can reduce the impact of the pressure wave. The higher the cross-section liquid holdup, the greater the pressure wave speed, and the shorter the propagation period will be. The larger the liquid holdup, the larger the variation range of pressure, and the greater the pressure will be. In actual production, the production parameters can be adjusted to get the appropriate liquid holdup, control the magnitude and range of fluctuation pressure, and reduce the impact of water hammer effect. When the valve closing time increases, the maximum fluctuating pressure value of the wellhead decreases, the time of pressure peak delays, and the pressure mutation area gradually disappears. The shorter the valve closing time, the faster the pressure wave propagates. Case simulation proves that the transient flow model of gas well can optimize the reasonable valve opening coefficient and valve closing time, reduce the harm of water hammer impact on the wellhead device and tubing, and ensure the integrity of the wellbore.展开更多
A new kinetic model for multiphase flow was presented under the framework of the discrete Boltzmann method(DBM).Significantly different from the previous DBM,a bottom-p approach was adopted in this model.The effects o...A new kinetic model for multiphase flow was presented under the framework of the discrete Boltzmann method(DBM).Significantly different from the previous DBM,a bottom-p approach was adopted in this model.The effects of molecular size and repulsion potential were described by the Enskog collision model;the attraction potential was obtained through the mean field approximation method.The molecular interactions,which result in the non-ideal equation of state and surface tension,were directly introduced as an external force term.Several typical benchmark problems,including Couette flow,two-phase coexistence curve,the Laplace law,phase separation,and the collision of two droplets,were simulated to verify the model.Especially,for two types of droplet collisions,the strengths of two non-equilibrium ffcts,D*2 and D*3,defined through the second and third order non-conserved kinetic moments of(f-feq),are comparatively investigated,where f(feq)is the(equilibrium)distribution function.It is interesting to find that during the collision process,D*2is always significantly larger than D*3,D*2 can be used to identify the different stages of the collision process and to distinguish different types of collisions.The modeling method can be directly extended to a higher.order model for the case where the non-equilibrium pffect is strong,and the linear constitutive law of viscous stress is no longer valid.展开更多
基金The work was supported by the National Natural Science Foundation of China(No.51874045)National Natural Science Foundation-Youth Foundation(52104056)+2 种基金Department of Natural Resources of Guangdong Province(GDNRC[2021]56)Postdoctoral innovative talents support program in China(BX2021374)Scientific Research Program of Hubei Provincial Department of Education(T2021004).
文摘A reliable multiphase flow simulator is an important tool to improve wellbore integrity and production decision-making.To develop a multiphase flow model with high adaptability and high accuracy,we first build a multiphase flow database with 3561 groups of data and developed a drift closure relationship with stable continuity and high adaptability.Second,a high-order numerical scheme with strong fault capture ability is constructed by effectively combining MUSCL technology,van Albada slope limiter and AUSMV numerical scheme.Finally,the energy equation is coupled into the AUSMV numerical scheme of the drift flow model in the form of finite difference.A transient non-isothermal wellbore multiphase flow model with wide applicability is formed by integrating the three technologies,and the effects of various factors on the calculation accuracy are studied.The accuracy of the simulator is verified by comparing the measurement results with the blowout experiment of a full-scale experimental well.
基金Supported by National Science and Technology Major Project of the Ministry of Science and Technology of China(2016ZX05026-002,2016ZX05028-001,2016ZX05024-005)
文摘As the classical transient flow model cannot simulate the water hammer effect of gas well, a transient flow mathematical model of multiphase flow gas well is established based on the mechanism of water hammer effect and the theory of multiphase flow. With this model, the transient flow of gas well can be simulated by segmenting the curved part of tubing and calculating numerical solution with the method of characteristic curve. The results show that the higher the opening coefficient of the valve when closed, the larger the peak value of the wellhead pressure, the more gentle the pressure fluctuation, and the less obvious the pressure mutation area will be. On the premise of not exceeding the maximum shut-in pressure of the tubing, adopting large opening coefficient can reduce the impact of the pressure wave. The higher the cross-section liquid holdup, the greater the pressure wave speed, and the shorter the propagation period will be. The larger the liquid holdup, the larger the variation range of pressure, and the greater the pressure will be. In actual production, the production parameters can be adjusted to get the appropriate liquid holdup, control the magnitude and range of fluctuation pressure, and reduce the impact of water hammer effect. When the valve closing time increases, the maximum fluctuating pressure value of the wellhead decreases, the time of pressure peak delays, and the pressure mutation area gradually disappears. The shorter the valve closing time, the faster the pressure wave propagates. Case simulation proves that the transient flow model of gas well can optimize the reasonable valve opening coefficient and valve closing time, reduce the harm of water hammer impact on the wellhead device and tubing, and ensure the integrity of the wellbore.
基金国家"863"计划"CO2驱油注采工程技术研究"(2009AA063404)国家科技重大专项"大型油气田及煤层气开发"(2008ZX05009-05)加拿大CMG基金会项目"Industrial Research Chair in Non-Conventional Reservoirs Modeling"
基金Many thanks to the anonymous referees for thelr helpful comments and suggestions.This work was supported by the China Postdoctoral Science Foundation Grant No.2019M662521,the National Natural Science Foundation of China under Grant No.11772064,CAEP Foundation(Grant No.CX201903)the Opening Project of State Key Laboratory of Explosion Science and Technology(Beiing Institute of Technology)under Grant No.KFJJ19-01 M.
文摘A new kinetic model for multiphase flow was presented under the framework of the discrete Boltzmann method(DBM).Significantly different from the previous DBM,a bottom-p approach was adopted in this model.The effects of molecular size and repulsion potential were described by the Enskog collision model;the attraction potential was obtained through the mean field approximation method.The molecular interactions,which result in the non-ideal equation of state and surface tension,were directly introduced as an external force term.Several typical benchmark problems,including Couette flow,two-phase coexistence curve,the Laplace law,phase separation,and the collision of two droplets,were simulated to verify the model.Especially,for two types of droplet collisions,the strengths of two non-equilibrium ffcts,D*2 and D*3,defined through the second and third order non-conserved kinetic moments of(f-feq),are comparatively investigated,where f(feq)is the(equilibrium)distribution function.It is interesting to find that during the collision process,D*2is always significantly larger than D*3,D*2 can be used to identify the different stages of the collision process and to distinguish different types of collisions.The modeling method can be directly extended to a higher.order model for the case where the non-equilibrium pffect is strong,and the linear constitutive law of viscous stress is no longer valid.
