Current status and future prospects of water jet technology in petroleum engineering in China

This paper reviews the developments of investigation and application of high pressure water jet technology in both deep drilling and oil production including jet-bit drilling, extended nozzles and their combination to enhance hydraulic effectiveness at bottomhole, combined jet and mechanical drilling, new efficient jets (self-resonating cavitating jet, self-excited oscillation jet, swirling jet) used in drilling, horizontal well drilling by water jet, near wellbore plug removal with water jet, and high pressure water jet penetrating. Laboratory investigation and field application have coherently shown that high pressure jet drilling can increase the penetration rate. The hydraulic power of rock bit with extended nozzles and with crossflow hydraulics can increase by 30 similar to 40 percent, the bit footage by 40 to 50 percent and dynamic pressure by 90 to 110 percent compared with conventional bit. Combined jet and mechanical drilling can increase drilling rate by a factor of 3 in deep wells than conventional drilling method. New efficient jets can improve the penetration rate of bit with 20 to 60 percent higher, owing to the enhanced cutting and cleaning action. High pressure water jet drilling system can be used to drill multiple ultra-short-radius (0.3 m) radial horizontal wells at the same level without tripping the whipstock. Near wellbore plug removal with hydraulically rotating and pulsating water jet can increase oil production by 20 to 50 percent and increase water injection by 30 to 90 percent. New penetrating system by using high pressure water jet cutting can produce unobstructed radial tunnels with 3 meters in length and 14-25 mm in diameter information rocks and can be used in new well completions, recompilations, and workovers of older wells to enhance the production and injection efficiency. The paper shows the brilliant prospects of development and application of water jet technology.