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Alternate Joint Locking Mechanism for Threaded Joint in ESP

IP.com Disclosure Number: IPCOM000244503D
Publication Date: 2015-Dec-17
Document File: 5 page(s) / 433K

Publishing Venue

The IP.com Prior Art Database

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Alternate joint locking mechanism for threaded joint in ESP

This disclosure relates to an alternate joint locking method meant for threaded joints in ESP that no longer requires lock weld. There's always a concern with the O-ring integrity when lock weld is performed onto the threaded joints because the heat might meld the O-ring. This disclosure described the use of one-directional wedges to mechanically lock the threaded parts to each other. This wedges will prevent the threaded parts from opening up.

Conventionally, downhole tools and equipment such as Electrical Submersible Pump (ESP) are constructed by assembling bodies and housings coaxially. These bodies and housing are joint together through the use of unified standard thread. For critical area where sealing of internal environment against external environment is required, elastomers such as O-ring and/or back up rings are used.

One common but important consideration for ESP is the resultant vibration from ESP operation. This is because the operational vibration is in traverse direction of the threaded joint axis. According to some sources, traverse vibration proved to have the worst loosening effect for threaded joints. As a result, these threaded joints are considered one of the weakest link in the whole ESP architecture.

Currently, the common practice is by using full lock weld or lock plate welding at the threaded joints for thread locking purpose. Regardless of the different welding technics, intense heat is introduced to the threaded joints during welding and this may melt the O-ring at the threaded joints. This undesirable effect might be the cause for many infant failures of ESP in the field. Therefore, it's important to have a method to reliably lock the threaded parts together without heat or damage to the O-ring.

This disclosure details a new method of threaded joint locking using a wedge-design edge for both threaded parts to mechan...