Advances in Coiled Tubing Jetting Technology

摘要

For many years, various types of simple nozzles have beenrnregularly used for wellbore cleaning with coiled tubing. Thisrnpaper describes the advances made in fluid jetting technology,rnassociated tools and the parameters that are crucial to thernefficiency of these techniques. A laboratory and field testingrnprogramme has been completed and data is included.rnBy detailed design of the internal fluid path, orifice geometry,rnjet stand off and pump rates, tool effectiveness has now beenrnimproved to a level several times more efficient thanrnpreviously available for the same feed pressures and flowrnrates. Pre-engineering using computer simulation to optimisernthe job design parameters has proven essential in designingrnclean out jobs and sizing the appropriate coiled tubing andrnpumping equipment.rnThree distinct categories of tools have emerged; conventionalrndrilled nozzles, non-rotating high-pressure nozzles and highrnpressure rotating tools.rnAll three types have gained a common advantage from therndevelopment of a Downhole Phase Separator. The high-energyrnlosses previously associated with a two-phase fluid necessaryrnin low hydrostatic wells can now be eliminated. A step changernin operational efficiency has resulted through combining thernmajor improvements in jetting tool design with the ability tornseparate gas and liquid phases downhole. With thisrndevelopment, the full benefits of using single phase fluidrnjetting can be realised in low hydrostatic wells.