Tool Design And Experimental Research On Swirling Abrasive Water Jet Cutting Window Technique

In all sort of oil recovery promoting techniques, the ultra-short radius radial drilling technique shows good technical and economic benefits with the advantages of simple operating procedure, short cycle time and less investment. The current small window ultra-short radius radial drilling technique's cutting window method is using a small positive displacement motor to drive an alloy bit to drill a small window on the casing. Due to downhole space limitation, domestic positive displacement motors can't meet the requirements. So the swirling abrasive water jet cutting window technique is introduced, its theoretical analysis, tool design and experimental research are carried out to advance the application of small window ultra-short radius radial drilling technique at home.Firstly combine the casing cutting mechanism of swirling abrasive water jet and the actual casing window requirements and design a set of impellers, nozzles and related tools for experimental research, and do strength check. The strength check result shows that the tools meet the requirements.Swirling water jet spread angle measuring experiment is carried out to analyze the effect of related parameters on the spread angle. The experimental study shows that the spread angle does not change with pump pressure under high pump pressure condition, it increases with the increase of nozzle size, impeller outlet angle and vane number.Swirling abrasive water jet cutting window experiment is carried out to analyze the effect of related parameters on the window and to select optimal parameters. The experimental study shows that the window diameter increases with the increase of nozzle size, standoff distance, impeller outlet angle and vane number, slightly increases with the increase of pump pressure, abrasive weight concentration and cutting time and with limitations; the cutting depth increases with the increase of pump pressure, abrasive weight concentration, nozzle size and cutting time, while decreases with the increase of standoff distance, impeller outlet angle and vane number. For this experiment, the threshold pressure for cutting 7″N80 type casing is 6.5809MPa.