Dissertation > Industrial Technology > Oil and gas industry > Drilling engineering > Drilling theory

Mechanism Study on the Bottomhole Pressure Reduction by Drilling Fluid Shunt on Bit

Author SunWeiLiang
Tutor YangYongYin
School China University of Petroleum
Course Oil and Gas Well Engineering
Keywords Bypass Bottomhole pressure differential ROP Numerical Simulation Experiment
Type Master's thesis
Year 2010
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Deep wells, ultra- deep well drilling process , the drilling speed increases with depth decreased significantly. One of the important reasons is due to the bottomhole pressure differential increases , the debris can not be cleared , resulting in repeated broken drill , resulting in the rapid decline of the ROP . The basic principles of speed drill from the bottom hole pressure differential impact shunt through the drill bit lower bottomhole pressure differential to reduce the hold effect \By theoretical analysis, the application of numerical simulation methods , changing the shunt nozzle , bit body flow channel structure parameters and hydraulic parameters , analysis bottomhole confining pressure , flow channel structure of the bit body , the nozzle throat diameter shunt flow ratio , shunt nozzle from the well the end of the position of the drill bit and the borehole wall gap factors reduce the bottomhole pressure to drill shunt law , the dimensionless pressure drop can reach 0.26 . Bistable fluidic element of the application attached wall for a co-ordinated pulsating streaming dimensionless pressure drop of up to 0.5 antihypertensive effect than continuity shunt . Experimental tools based on numerical simulation drill wellbore model design experiments , analysis of confining pressure shunt flow ratio diversion nozzle distance to the bottom position , drill the borehole wall gap shunt antihypertensive effect of various factors , no times voltage drop to a maximum of 0.35 , the experimental results and numerical simulation results are consistent . Finally, the application of PDC bit design software , combined with the conclusion of the numerical simulation and laboratory experiments , conducted a the triage drill bit structure and hydraulic parameters design , laid the foundation for further research and development of new and efficient drill .

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