Design And Experimental Study On PDC Bit Of Particle Impact Drilling

Particle impact drilling technology is one of the key technologies for improving the drilling speed of hard,extremely hard formations and strong abrasive formations in recent years,which can effectively increase drilling efficiency and reduce drilling costs.In particle jet impingement drilling technology,the design and manufacture of particle jet impact drill bits is an important part of this technology.In response to the Chuanqing Drilling Particle Jet Drilling Project,a new PDC bit model was designed based on the Xujiahe Formation data in the southwestern Sichuan Basin.The PDC bit was modified and optimized,and the PDC drill bit bottom hole was numerically simulated and experimentally studied.The flow field morphology and laws were studied.Firstly,referring to the drilling speed and hydraulic parameter calculations provided by Chuanqing drilling,a particle jet impact drilling PDC bit was designed: the hydraulic structure is obtained from the nozzle structure,number of nozzles and diameter,nozzle angle and position in three directions The experimental results were comprehensively designed;the mechanical structure was comprehensively designed from the aspects of machining method,blade structure,radial teeth,principle of cloth teeth and side angle of caster,and the structural optimization design of the initial model.Using ANSYS CFX software to simulate the bottom hole flow field of particle jet impact drilling PDC bit to verify the feasibility of the drill bit model.The two-phase flow model selects the multi-phase flow DPM model coupling and divides the whole flow field structure into drilling fluid structure.The map and the particle trajectory map are divided into regions and their influence laws on the bit body are analyzed.Analysis of the influence of drilling fluid viscosity,bit pressure drop,and cavity shape on bottom hole flow field morphology,and finally concluded that the streamlined cone cavity with flat cylindrical steps is most suitable for the design requirements of the cavity of particle jet impact drilling,and according to Simulation rules optimize the drill bit design and improve the final model.Finally,this particle impact drilling PDC drill bit was used to perform indoor rock breaking test with a full-scale drill bit.Under laboratory conditions,the penetration rate of the granite can reach 2.4 m/s,and the limestone can reach 1.9 m/s,and the ideal rock breaking effect can be obtained.With design feasibility,it comes expected requirements.