Method for determining gap between auxiliary shoulders of double-shoulder drill pipe joint

Abstract

The invention provides a method for determining a gap between auxiliary shoulders of a double-shoulder drill pipe joint. The method comprises the steps that a three-dimensional geometric model of thedouble-shoulder drill pipe joint is established according to the measured size data, and is subjected to grid division based on a multiblock grid method, and a three-dimensional elastoplastic finite element calculation model of the double shoulder drill pipe joint is established; on this basis, the three-dimensional force characteristics of double-shoulder drill pipe joints with different auxiliary shoulder gaps under the action of different axial forces are obtained based on the three-dimensional elastoplastic finite element analysis; and the gap between the auxiliary shoulders of the double-shoulder drill pipe joint which is most suitable for the axial force characteristics of a well section is preferably determined according to the depth characteristics of each section of a drill stem in ultra-deep well drilling operation. The method can determine the optimal gap between the auxiliary shoulders of the double-shoulder drill pipe joint so as to meet the requirements of different welldepth operations, and has very important significance on the improvement of the usability of the double-shoulder drill pipe joint, the prolonging of the service life of the double-shoulder drill pipejoint, and the reduction of the operation cost.

Description

technical field [0001] The invention relates to the technical field of oilfield drilling, in particular to a method for determining the secondary shoulder clearance of a double-shoulder drill pipe joint. Background technique [0002] With the development of oil and gas well drilling and production operations toward larger well depths and more severe service conditions and the technological progress of oil drilling and production technology itself, the commonly used API standard drill pipe joints have been difficult to meet the requirements of further development of oil and gas fields. Large drill pipe manufacturers have successively developed double-shoulder drill pipe joints with higher torsional performance. Since the double-shoulder drill pipe joint has better solved the problems of insufficient torsion resistance and serious stress concentration of the API standard drill pipe joint, its application range has been continuously expanded. [0003] The continuous reduction ...

AI Technical Summary

Problems solved by technology

Facing the increasingly harsh drilling operation environment of deep wells, ultra-deep wells and ultra-deep wells, double-shoulder drill pipe joint failure accidents still occur from time to time during field operations, causing huge economic losses to the oil field

The axial force borne by the drill string increases with the increase of the well depth, which limits the further development of the performance of the double-shoulder drill pipe joint

The auxiliary shoulder clearance has an important influence on the connection strength and sealing performance of the double-shoulder tool joint in use, but there is no method for determining the auxiliary shoulder clearance of the double-shoulder tool joint under different well depths and different axial forces. See the report

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