内凹型单牙轮-PDC复合钻头井底流场与冲蚀特性分析

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关键词：复合钻头；冲蚀磨损；井底流场；PDC齿数值模拟；钻头寿命中图分类号：TE921文献标识码：A DOI：10.12473/CPM.202504067

Abstract：The new hybrid bit with central-grooved single-cone & multi-blade combines the advantages of PDC bit and single-cone bit，and efectively improves the rock-breaking efciency in deep and ultra-deep wel drilling.However，theconcave-type structure and multi-nozzle layout make thedownhole flow field more complex and the erosion wear phenomenon more remarkable.To reveal the erosion wear mechanism，the coupled computational fluid dynamics （CFD）and discrete phase model （DPM）method was employed to establish a numerical modelof downholeflow fieldof the concave-type single-cone-PDC hybrid bit.Theefects of drilling fluid discharge rate，cuttings diameterandcuttings massflow rateonerosion wear were investigated，and fiting formulasfordifferentfactors on erosionrate were proposed.The studyresults show that increasing the drilingfluid discharge rate significantly enhances the jet flow kinetic energy，causing the erosion rate to rise from 5.0×10-7kg/（m2⋅s） to 19.5× （204号 ，with erosion hotspots concentrated at the nozzle outlet and concave center region. Larger cuttings diameter increasesparticle kineticenergy and inertia，leading to high-frequency cyclic impacts at the nozzle outlet，blade front and concave center region.Highercuttings mass flow rate notably elevates particle impact frequency，resulting in an upwardtrend in erosion rate and intensified erosion wear atthe concave center region and nozzleoutlet.The study results providea theoretical basis for the hydraulic structure optimization and anti-erosion design of the hybrid bit with central-grooved single-cone& multi-blade.

Keywords：hybrid bit;erosion wear;downhole flow field;numerical simulation;bit life

0 引言

随着全球油气勘探开发向深部和超深部地层不断推进，钻井工程面临着高温高压、复杂地层以及多变流体环境等诸多挑战[1-3]。（剩余12805字）