焊管2026，Vol.49Issue(5)：62-68,7.DOI:10.19291/j.cnki.1001-3938.2026.05.009
BJC-FJ直连型特殊螺纹套管开发
Development of BJC-FJ Flush Joint Connection Premium Threaded Casing
摘要
Abstract
Aiming at the challenges of limited drift diameter,high running friction,low tensile efficiency,and insufficient sealing reliability under cyclic loading associated with traditional coupling-type casings in the casing-in-casing wellbore reconstruction process for old wells,this paper develops the BJC-FJ flush joint connection two-stage metal-sealed premium casing.This product is specifically designed for ultra-narrow gap working conditions such as old well repair and wellbore reconstruction.An innovative connection structure featuring a hook-type buttress thread+two-stage metal seal+reverse double positioning shoulderwas designed to achieve the unification of maximized inner drift diameter and superior gas sealing performance within the same specification.Through numerical simulation and full-scale physical performance evaluation,the gas sealing reliability of the joint under combined loads of tension/compression,internal/external collapse pressure was verified.Experimental data demonstrate that the Φ88.9 mm×6.45 mm 125V BJC-FJ connection possesses excellent connection strength and anti-leakage capabilities.Field application results confirm that the BJC-FJ flush joint connection casing successfully meets the rigorous requirements for casing running,cementing operations,and large-scale repeated fracturing treatments.This study verifies that the BJC-FJ flush joint connection premium casing effectively resolves the contradiction between drift diameter and sealing performance in wellbore reconstruction,providing reliable key equipment support for the efficient potential tapping of old wells in unconventional oil and gas reservoirs.关键词
直连型特殊螺纹套管/井筒重构/套中固套/两级金属密封Key words
flush joint connection premium thread casing/wellbore reconstruction/casing-in-casing/two-stage metal seal分类
能源科技引用本文复制引用
李兴华,周新义,孙孟珂,于会永,焦文夫,李旭阳,汪强..BJC-FJ直连型特殊螺纹套管开发[J].焊管,2026,49(5):62-68,7.基金项目
陕西省重点研发计划"基于页岩气井套损机理研究的超高强度气密封特殊螺纹套管研制与应用"(项目编号2025QY-GJHX-09). （项目编号2025QY-GJHX-09）
