Optimum Design of Special Thread of New Drilling Tools
As exploration and development moves into deeper reservoirs,higher requirements are put forward for the connection strength of Drilling tools joints.According to the mechanical characteristics of the thread teeth when the drill pipe joint is loaded,a new type of special thread joint with double shoulder serrated thread teeth is designed.The inner surface of the structure is smooth,the pressure consumption is reduced,and the thread taper is small.Based on the theoretical calculation formula of joint torsion resistance and the principle of thread de-formation,a new type of special thread structure of drilling tool is proposed in this paper.Orthogonal optimiza-tion method was used to optimize the structure parameters,and the optimal parameters were obtained,taper 1:16,pitch 7.25 mm,tooth height 4.10 mm,bearing angle-3°,guiding angle 45°.Then ABAQUS is used to compare and calculate the bearing capacity of common joint,double shoulder joint and special thread joint of drill pipe under combined tension and torsion combined load in the well.The results show that compared with the or-dinary joint and the double shoulder joint,the water hole of the new drill pipe special thread joint is increased by 10.3％,the tensile property is increased by 15.4％and 10.9％,the stress concentration is optimized by 22.0％and 16.6％,and the fatigue life of the special thread joint is increased by 11.2％and 7.6％.
tool jointspecial threadorthogonal optimizationbearing capacityfinite element analysis
NETL
NSTL
万方数据
维普
