Investigation Of The Flow Field Of Radial Horizontal Drilling Nozzles Using Particle Image Velocimetry And CFD Techniques

Radial horizontal drilling is an efficient way to enhance oil recovery and increase the near wall permeability.Radial horizontal drilling nozzles are the core component of the radial horizontal drilling technique.It provides the rock breaking energy while drilling and more importantly,its perimeter directly determined the rock breaking efficiency and the extension limit.Currently,the investigation on the perimeters of the drilling nozzle are primarily using CFD technique and laboratory experiments.CFD technique is a theoretical method,which can hardly simulate the real flow status.Laboratory experiment can only test the rock breaking efficiency using the rock breaking results,which cannot test the inner flow field of the nozzles.The CFD method and the Particle Image Velocimetry(PIV)technique are both used in this paper to investigate the flow field of the radial horizontal drilling nozzles.The single-hole nozzle,multi-hole nozzle and a series of single-hole swirling nozzles are tested using both techniques.The flow field acquired using both techniques are compared to demonstrate the advantages and the disadvantages of the techniques.Using the CFD method,we reached the following conclusions.Single hole swirling nozzles can form regular radial horizontal wells,the shape of which is much better than the single-hole nozzle and multi-hole nozzle.Based on the PIV test of 5 different kinds of single-hole swirling nozzles,we found that the perimeters of the impeller have great impact on the flow field.Decrease the flow channel of the impeller can greatly increase the rotation effect of the flow field and increase the length of the impeller only have limited influence on the rotation effect.Based on the PIV test,we reached the following conclusions.Real flow field of radial horizontal drilling nozzles have turbulence,which is clearly different with the numerical simulation results.The radial velocity at 20 times jet distances of the single swirling nozzle have the N shape distribution,which is constant with the CFD results.Besides,the NO.5 impeller,which have the smallest flow channel,generated the most intense swirling jet,the radial velocity at 20 times jet distance is about 0.2m/s.