Optimization design method for non-API (American petroleum institute) thread sealing face

Abstract

The invention relates to an optimization design method for a non-API (American petroleum institute) thread sealing face. The method includes: constructing an optimization objective function according to the sealing quantity requirement of a plurality of limited condition loading points; describing the shape of the sealing face of an internal thread and an external thread with non-uniform B-spline curves; using control vertex coordinates of characteristic polygon of the non-uniform B-spline curves as variables of the optimization design; determining constraint conditions of the variables of the optimization design according to diameter parameter range requirements of oil bushing sealing face and upper limit requirements of contact interference of the sealing face; using numerical simulation of finite element to build the objective function of sealing of the sealing face and connection among different shape design variables of the sealing face; constructing test data points used for evaluating response function via numerical simulation; constructing an optimization model; using non-dominated sorting genetic algorithm modifier based on robust design method to implement multi-object optimization; and determining Pareto optimal solution collection. By the method, targeted and precise control of sealing integrity of threaded connectors is achieved.

Description

technical field [0001] The invention relates to the technical field of thread sealing surface optimization, in particular to a non-API thread sealing surface optimization design method. Background technique [0002] With the continuous development of exploration and development of high-pressure gas wells, non-API threaded oil casings with gas sealing capabilities have been more and more widely used. API (American Petroleum Institute) is the abbreviation of the American Petroleum Institute, which meets the standards specified by the American Petroleum Institute. The casing is called the API standard oil casing. The products specified in the API standard include tubing, casing, drill pipe, drill stringer, line pipe, etc. API standard threaded oil and casing have been used in the petroleum industry for decades. For a long time, it still plays a very important role. However, with the emergence of a large number of harsh well conditions such as deep wells, ultra-deep wells, high...

AI Technical Summary

Problems solved by technology

Its virtual fitness evaluation process only obtains and evaluates the Pareto ranking values ​​of all genetic individuals through non-dominated sorting, so that it is constantly approaching the frontier of the optimal solution set, but cannot evaluate the population density information around individuals at different levels, so sometimes there will be different optimization trends Individuals still have the same chance to reproduce offspring, which reduces the optimization efficiency

In addition, for solving the huge multi-objective optimization problems constructed based on complex engineering cases, especially for the optimization problems whose objective functions cannot be directly analyzed from the design variables, this method resorts to a large number of genetic operations, which greatly reduces the design efficiency, and is not suitable for non- Optimal Design of API Thread Sealing Surface

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