Method for determining ultimate operating torque of tool joint under complex working conditions

Abstract

The invention provides a method for determining ultimate operating torque of a tool joint under complex working conditions. According to the method, fem pre-processing software is adopted to perform grid division on the three-dimensional geometric model of the tool joint; the three-dimensional finite element model of the tool joint is built; non-linear finite element analysis software ABAQUS is adopted to calculate so as to obtain the mechanical property of the tool joint under a shaft under the action of actual load working conditions; the ultimate operating torque which can be born by the tool joint is calculated on the basis of the mechanical property of the tool joint. The evaluation method provided by the invention can be used for evaluating the ultimate operating torque of the tool joint under the action of complex external load such as make-up torque, axial tension and bending moment, thereby evaluating the security of the tool joint, and has important meaning for recognizing the load limit of the tool joint, guiding the improvement of the structure parameter and selection of the working parameter of the tool joint and guaranteeing the safety of drilling operation.

Description

technical field [0001] The invention relates to the technical field of oilfield drilling, in particular to a method for determining the limit working torque of a drill tool joint under complex working conditions. Background technique [0002] Drilling tools are the main tools used to transmit power and transport drilling fluid, and play an important role in the drilling process of oil and gas fields. Drilling tool failure accidents often bring huge economic losses to oil fields. According to the statistical analysis of drill string failure accidents, 65% of the failure accidents occurred at the drill pipe joints. With the number of deep wells, ultra-deep wells and extended-reach horizontal wells increasing year by year, the torsional performance of drill tool joints has received more and more attention. In particular, when encountering the complex working conditions of downhole stuck pipe, due to the large axial load, if it is necessary to choose the measure of rotating the...

AI Technical Summary

Problems solved by technology

However, the two-dimensional axisymmetric model is difficult to evaluate the force characteristics of the tool joint under complex working conditions such as make-up torque and bending moment, so it is also difficult to reflect the ultimate working torque of the tool joint

[0004] Although the API standard provides the torsional strength of the drill tool joint, it fails to consider the load conditions such as axial tension and bending moment, so it is difficult to reflect the torsional strength of the downhole drilling tool under real working conditions

Images