It is very important to understand the annular multiphase flow behavior and the effect of hydrate phase transition during deep water drilling. The basic hydrodynamic models, including mass, momentum, and energy conser...It is very important to understand the annular multiphase flow behavior and the effect of hydrate phase transition during deep water drilling. The basic hydrodynamic models, including mass, momentum, and energy conservation equations, were established for annular flow with gas hydrate phase transition during gas kick. The behavior of annular multiphase flow with hydrate phase transition was investigated by analyzing the hydrate-forming region, the gas fraction in the fluid flowing in the annulus, pit gain, bottom hole pressure, and shut-in casing pressure. The simulation shows that it is possible to move the hydrate-forming region away from sea floor by increasing the circulation rate. The decrease in gas volume fraction in the annulus due to hydrate formation reduces pit gain, which can delay the detection of well kick and increase the risk of hydrate plugging in lines. Caution is needed when a well is monitored for gas kick at a relatively low gas production rate, because the possibility of hydrate presence is much greater than that at a relatively high production rate. The shut-in casing pressure cannot reflect the gas kick due to hydrate formation, which increases with time.展开更多
Sand particle erosion is always a challenge in natural gas production.In particular,the erosion in gas-liquid-solid annular flow is more complicated.In this study,a three-phase flow numerical model that couples the vo...Sand particle erosion is always a challenge in natural gas production.In particular,the erosion in gas-liquid-solid annular flow is more complicated.In this study,a three-phase flow numerical model that couples the volume of fluid multiphase flow model and the discrete phase model was developed for prediction of erosion in annular flow.The ability of the numerical model to simulate the gas-liquid annular flow is validated through comparison with the experimental data.On the basis of the above numerical model,the phase distribution in the pipe was analyzed.The liquid entrainment behavior was reasonably simulated through the numerical model,which guaranteed the accuracy of predicting the particle erosion.Additionally,four erosion prediction models were used for the erosion calculation,among them,the Zhang et al.erosion model predicted the realistic results.Through the analysis of the particle trajectory and the particle impact behavior on the elbow,the cushion effect of the liquid film on the particles and the erosion morphology generation at the elbow were revealed.展开更多
基金supported by the China National 863 Program (Grant No.2006AA09A106)the Doctoral Program of Higher Education of China (Grant No.20060425502)+1 种基金the National Natural Science Foundation of China (Grant No.50874116)Shandong Province Natural Science Foundation(Grant No.Z2007A01)
文摘It is very important to understand the annular multiphase flow behavior and the effect of hydrate phase transition during deep water drilling. The basic hydrodynamic models, including mass, momentum, and energy conservation equations, were established for annular flow with gas hydrate phase transition during gas kick. The behavior of annular multiphase flow with hydrate phase transition was investigated by analyzing the hydrate-forming region, the gas fraction in the fluid flowing in the annulus, pit gain, bottom hole pressure, and shut-in casing pressure. The simulation shows that it is possible to move the hydrate-forming region away from sea floor by increasing the circulation rate. The decrease in gas volume fraction in the annulus due to hydrate formation reduces pit gain, which can delay the detection of well kick and increase the risk of hydrate plugging in lines. Caution is needed when a well is monitored for gas kick at a relatively low gas production rate, because the possibility of hydrate presence is much greater than that at a relatively high production rate. The shut-in casing pressure cannot reflect the gas kick due to hydrate formation, which increases with time.
基金support of National Natural Science Foundation of China(No.51874340)Natural Science Foundation of Shandong Province(No.ZR2018MEE004)National Key R&D Program of China(No.2016YFC0802302).
文摘Sand particle erosion is always a challenge in natural gas production.In particular,the erosion in gas-liquid-solid annular flow is more complicated.In this study,a three-phase flow numerical model that couples the volume of fluid multiphase flow model and the discrete phase model was developed for prediction of erosion in annular flow.The ability of the numerical model to simulate the gas-liquid annular flow is validated through comparison with the experimental data.On the basis of the above numerical model,the phase distribution in the pipe was analyzed.The liquid entrainment behavior was reasonably simulated through the numerical model,which guaranteed the accuracy of predicting the particle erosion.Additionally,four erosion prediction models were used for the erosion calculation,among them,the Zhang et al.erosion model predicted the realistic results.Through the analysis of the particle trajectory and the particle impact behavior on the elbow,the cushion effect of the liquid film on the particles and the erosion morphology generation at the elbow were revealed.
