Quick make-up screw thread structure for expansion pipe under large expansion rate and its processing and preparation method

Abstract

The invention provides a rapid buckling threaded structure for an expansion pipe in the large expansion rate. A direct connection threaded structure is adopted, and the threaded connector comprises an expansion pipe female buckle and an expansion pipe male buckle; the expansion pipe female buckle is sequentially provided a low-conicity single-hook-type female thread, tool withdrawal grooves, cylindrical surface sealing segments, a first-stage sealing groove and / or a second-stage sealing groove, conical surface sealing segments and negative-angle torque shoulders from the end to the interior; the expansion pipe male buckle is sequentially provided negative-angle torque shoulders, conical surface sealing segments, cylindrical surface sealing segments and a single-hook-type male thread from the end to the interior; the threaded connector adopts a double-channel multi-stage sealing structure, and particularly adopts a double-channel sealing mode of a third-stage sealing structure before expansion and a second-stage sealing structure after expansion. According to the rapid buckling threaded structure for the expansion pipe in the large expansion rate, the high-leakproofness property of the threaded connector deformed in the large expansion rate are achieved by adopting the optimized double-channel multi-stage sealing structure; meanwhile, the mutual buckling and buckling speed is increased through the optimal design on the thread pitch and the thread form, and therefore rapid buckling of the thread is achieved; in addition, machining and detecting are easy.

Description

technical field [0001] The scope of the invention relates to the design of connection thread structure of drilling and completion production strings in the petroleum and natural gas industry, and in particular to a large expansion rate expansion pipe used in casing damage compensation, formation plugging and open hole completion, which has high sealing and fast make-up capability The threaded joint design method to ensure the safe and effective exploitation of oil and gas wells. Background technique [0002] With the further deepening of oil and gas development, the drilling depth is getting deeper and deeper, and the development is becoming more and more difficult. Difficulties, increase the speed of drilling and production, save drilling costs, solid expansion tube technology has been introduced into the drilling and completion process and has excellent performance. [0003] The basic principle of solid expansion pipe technology is to run a steel pipe with good plasticity...

AI Technical Summary

Problems solved by technology

Since the solid expansion pipe thread needs to undergo a diameter-expanding deformation during use, it needs to achieve a certain sealing and load-bearing performance after deformation, and the requirements for the sealing and integrity of the thread are higher. Ordinary API thread and general casing special thread The structure simply does not meet the needs

In recent years, some expansion pipe thread structures have appeared, but they are mainly aimed at low expansion rate (below 15%), and the sealing pressure is not high, which makes it impossible to use under high expansion deformation rate or high sealing performance after expansion. , greatly restricting the development and application of expansion tube technology

At present, with the advancement of expandable tube technology, especially the demand for formation plugging and marine expandable tube technology, higher requirements are put forward for the expansion rate of the expandable tube, the tightness and structural integrity after expansion, especially for marine solid expansion. In the process of offshore oil and gas development, there is a high requirement for the speed of the expansion pipe to go down the well. If the conventional expansion pipe thread design is used, the make-up time is long and the efficiency is low, which cannot meet the needs of emergency accidents and well workover. At the same time, due to offshore drilling The daily operating cost of the platform is high, and increasing the make-up speed can significantly reduce the undertaking. Therefore, there is an urgent need for a special threaded joint structure design for expansion pipes that can meet the requirements of large expansion rates, high sealing and fast make-up.

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