Analysis On Flow Field And Wear Properties Of Hydra-jet Fracturing Tool

Hydra-jet fracturing is one of the most important stimulation methods combined with hydraulic perforating,fracturing and hydraulic sealing in recent years,which has a vital significance and broad prospect for the development of low permeability and thin reservoir.Because of the large flow rate and high sand concentration during fracturing,the tool wears greatly by high speed particle,which is easy to cause nozzle washout and tool leakage,making tool failure and having a significant impact on fracturing operation.Therefore,it is necessary to study and predict the flow field and erosion distribution of the hydra-jet fracturing tool,and to find out the erosion principle,so as to improve the tool structure and success rate of fracturing operation and extend the tool life.In this paper,the distribution of internal flow field of hydra-jet fracturing tool was firstly simulated based on the discrete phase model and Euler model.The influence of jet pressure and sand volume fraction to the nozzle flow filed and sand distribution inner the tool was further studied.The results show that there exist differences in the flow rate distribution between upper and lower nozzles.Both the liquid flow rate and sand flow rate of lower nozzles are larger than upper nozzles.Sand distribution in different positions of the tool is obviously different.Sand is mainly gathered around the nozzle area of the tool wall.Sand is drop-shaped distributed in the lower part of upper nozzles and ring-shaped distributed in the around of lower nozzles.Secondly the erosion distribution characteristics of nozzle inlet area was mainly simulated,and the influence of flow rate,particle diameter and particle mass concentration on the erosion was further studied.The results show that severe eroded areas are located in the upper part of upper nozzles and lower part of lower nozzles.The average erosion rate of lower nozzle is higher than that of upper nozzle.The effectiveness of the numerical simulation results was verified by comparing with the actual tool erosion.