Research On Material And Structure Optimization Of Roller Bits Based On Wear Mechanism

Faced with rising oil prices,reducing drilling costs has become an inevitable trend.Roller bit is one of the commonly used drilling tools.One of the failure modes is the wear of the roller bit,which brings great challenges to the rapid drilling of the roller bit.Based on the research of the existing roller cone bit,combined with the numerical simulation of finite element method and the wear theory method,the tooth wear mechanism of the roller cone bit is studied,and the structure of the cone and the material are optimized.This paper mainly carried out the following work:Firstly,the geometric model of the tri-cone bit was established.The finite element numerical simulation method was used to simulate the location of the cuttings and the spatial distribution law.The wear of the cuttings on the teeth of the roller bit was studied.The numerical simulation of the flow field at the bottom of the well was established,and the flow law of the cuttings under the action of drilling fluid was simulated.The process of cutting debris caused by the second scraping of the innermost teeth of the roller bit was explored.Secondly,the mathematical model of the wear of the cone-shaped drill bit in composite motion is established.The wear program is programmed by the sub-program interface.Then the finite element model of single-tooth wear is established and the wear model is verified.Finally,based on the wear theory of roller bit wear,the new thermal processing scheme and the current thermal processing scheme were compared by numerical simulation,and the material properties and organization of the two thermal processing techniques were analyzed.Based on the characteristics of the cone bit working and the mechanism of the roller bit wear,the arrangement of the tooth angle and the tooth on the cone is optimized.