Understanding the kinetics and viscosity of hydrate slurry in gas-water-sand system is of great significance for the high-efficiency and high-safety development of natural gas hydrates.The effect of micronsized sands ...Understanding the kinetics and viscosity of hydrate slurry in gas-water-sand system is of great significance for the high-efficiency and high-safety development of natural gas hydrates.The effect of micronsized sands with various concentrations and particle sizes on the hydrate formation,dissociation,and viscosity in gas-water-sand system are investigated in this work.The experimental results show that the hydrate induction time in the sandy system is slightly prolonged compared to the pure gas-water system,and the inhibition effect first strengthens and then weakens as the sand concentration increases from0 wt%to 5 wt%.Besides,the difference of hydrate formation amount in various cases is not obvious.The concentration and particle size of sand have little effect on the kinetics of hydrate formation.Both promoting and inhibiting effects on hydrate formation have been found in the sandy multiphase fluid.For the viscosity characteristics,there are three variations of hydrate slurry viscosity during the formation process:Steep drop type,S-type and Fluctuation type.Moreover,appropriate sand size is helpful to reduce the randomness of slurry viscosity change.Meanwhile,even at the same hydrate volume fraction,the slurry viscosity in the formation process is significantly higher than that in dissociation process,which needs further research.This work provides further insights of hydrate formation,dissociation,and viscosity in gas-water-sand system,which is of great significance for safe and economic development of natural gas hydrates.展开更多
With the exploration and development of oil and gas fileds going towards into deep-water fields,high waxy reservoir has much more flow assurance issues of encourage complex solids depositions in the transportation sys...With the exploration and development of oil and gas fileds going towards into deep-water fields,high waxy reservoir has much more flow assurance issues of encourage complex solids depositions in the transportation system,especially hydrates and wax.Applying risk management such as hydrate slurry technology to control hydrate blockage,has much more economic and technical advantages,comparing to the traditional methods.It is significant to understand the viscosity of the waxy-hydrate slurry using hydrate slurry technology in high wax content reservoir.In this work,based on a simplification idea by coupling the wax content effect into the viscosity,volume and density of the water-in-waxy oil emulsion,a new viscosity model of waxy-hydrate slurry is established according to the Einstein effective medium theory,based on the experiments carried out in a high-pressure rheology system with different wax contents ranging from 0.5 wt%~2.0 wt%.The effect of the complex aggregate coupling wax-hydrate-water is considered by function the non-Newtonian coefficient by four dimensionless parameters.Well-fitting results within an improved deviation of±15%indicate the feasibility of this method is feasibility.This work can provide a valuable reference for the application of hydrate slurry technology in deep-water fields with high wax content reservoir.展开更多
基金supported by the National Natural Science Foundation of China[Grand numbers:52104069,51874323,U20B6005]China Postdoctoral Science Foundation[Grand number:2022M713460]Science Foundation of China University of Petroleum,Beijing[Grand number:2462020YXZZ045]。
文摘Understanding the kinetics and viscosity of hydrate slurry in gas-water-sand system is of great significance for the high-efficiency and high-safety development of natural gas hydrates.The effect of micronsized sands with various concentrations and particle sizes on the hydrate formation,dissociation,and viscosity in gas-water-sand system are investigated in this work.The experimental results show that the hydrate induction time in the sandy system is slightly prolonged compared to the pure gas-water system,and the inhibition effect first strengthens and then weakens as the sand concentration increases from0 wt%to 5 wt%.Besides,the difference of hydrate formation amount in various cases is not obvious.The concentration and particle size of sand have little effect on the kinetics of hydrate formation.Both promoting and inhibiting effects on hydrate formation have been found in the sandy multiphase fluid.For the viscosity characteristics,there are three variations of hydrate slurry viscosity during the formation process:Steep drop type,S-type and Fluctuation type.Moreover,appropriate sand size is helpful to reduce the randomness of slurry viscosity change.Meanwhile,even at the same hydrate volume fraction,the slurry viscosity in the formation process is significantly higher than that in dissociation process,which needs further research.This work provides further insights of hydrate formation,dissociation,and viscosity in gas-water-sand system,which is of great significance for safe and economic development of natural gas hydrates.
基金the Beijing National Natural Science Foundation of China(Grant No.3192027)National Natural Science Foundation of China(Grant No.U20B6005,52104069,51874323)Science Foundation of China University of petroleum-Beijing(Grant No.2462020YXZZ045,2462020XKBH012),which are gratefully acknowledged.
文摘With the exploration and development of oil and gas fileds going towards into deep-water fields,high waxy reservoir has much more flow assurance issues of encourage complex solids depositions in the transportation system,especially hydrates and wax.Applying risk management such as hydrate slurry technology to control hydrate blockage,has much more economic and technical advantages,comparing to the traditional methods.It is significant to understand the viscosity of the waxy-hydrate slurry using hydrate slurry technology in high wax content reservoir.In this work,based on a simplification idea by coupling the wax content effect into the viscosity,volume and density of the water-in-waxy oil emulsion,a new viscosity model of waxy-hydrate slurry is established according to the Einstein effective medium theory,based on the experiments carried out in a high-pressure rheology system with different wax contents ranging from 0.5 wt%~2.0 wt%.The effect of the complex aggregate coupling wax-hydrate-water is considered by function the non-Newtonian coefficient by four dimensionless parameters.Well-fitting results within an improved deviation of±15%indicate the feasibility of this method is feasibility.This work can provide a valuable reference for the application of hydrate slurry technology in deep-water fields with high wax content reservoir.
