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Seal Bore with Pressure By-Pass Channel

IP.com Disclosure Number: IPCOM000243480D
Publication Date: 2015-Sep-24
Document File: 1 page(s) / 17K

Publishing Venue

The IP.com Prior Art Database

Abstract

A Seal Bore Sub is designed with porous metal at the ID near the exit of the bore. A channel lies outside the porous metal but in communication with it. The channel runs in an axial direction for the length of the porous metal. A seal beginning to exit such a Seal Bore Sub while still under differential pressure would see pressure traverse the porous metal and enter the channel. Pressure would be then be applied to the back side of the seal while it is still contained in the bore. When the seal does exit, it would do so under considerably less differential pressure so that damage to the seal could be minimized or eliminated Seal Bores are used in subterranean wells to provide a means of sealing a tubing string to a liner. Typically, they comprise a tube with threads on either end for attachment to the liner and with a polished bore to provide a location for sealing. The length of the polished bore can be quite long (> 10 ft) and the tubing can have several seal stacks on it so that a seal is maintained between the two in spite of significant linear movement of the tubing. This allows for tubing expansion and contraction downhole due to thermal changes. Seal stacks may exit a seal bore while still under a pressure differential. Some seals, such as bonded seals, can handle some of this "pressure unloading" and may have pressure ratings of up to 5,000 psi differential under such applications. Other seals, for instance lip seals (V-Ring stack) or O-Rings, are not recommended for service where pressure unloading is anticipated. The proposed concept, is a special Seal Bore Sub designed to allow seals to exit without sustaining severe damage due to pressure unloading. In this concept, the Seal Bore Sub is made by 3-d printing (additive manufacturing) so that an internal channel extends for several inches into the bore from each end. The channel may be a small axial hole or a series of holes spaced in a bolt circle around the axis of the part. The material between the channel and the ID is less dense that the middle section of the Seal Bore Sub. That is, the ID surface is dense enough so that the lips of the seals can't penetrate, catch and be damaged; yet, the surface is porous enough to let pressure through. For the tubing to be sealed properly, the seals must be positioned in the interior of the Seal Bore Sub away from this porous material. As the seals are withdrawn, as soon as the last seal from the stack enters the porous region, pressure is free to traverse the porous material and enter the Bypass Channel. The idea is for the pressure to continue unabated through the channel to reach the end of the seal bore before the seal stack reaches that point. In that manner, pressure begins to be applied to the back side of the seals while they are still contained in the ID of the Seal Bore Sub. Once they begin to exit, the pressure differential across the seals has been significantly reduced, hopefully to the point of eliminating severe damage to the seals

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Seal Bore with Pressure By-Pass Channel

A Seal Bore Sub is designed with porous metal at the ID near the exit of the bore. A channel lies outside the porous metal but in communication with it. The channel runs in an axial direction for the length of the porous metal. A seal beginning to exit such a Seal Bore Sub while still under differential pressure would see pressure traverse the porous metal and enter the channel. Pressure would be then be applied to the back side of the seal while it is still contained in the bore. When the seal does exit, it would do so under considerably less differential pressure so that damage to the seal could be minimized or eliminated

Seal Bores are used in subterranean wells to provide a means of sealing a tubing string to a liner. Typically, they comprise a tube with threads on either end for attachment to the liner and with a polished bore to provide a location for sealing. The length of the polished bore can be quite long (> 10 ft) and the tubing can have several seal stacks on it so that a seal is maintained between the two in spite of significant linear movement of the tubing. This allows for tubing expansion and contraction downhole due to thermal changes. Seal stacks may exit a seal bore while still under a pressure differential. Some seals, such as bonded seals, can handle some of this "pressure unloading" and may have pressure ratings of up to 5,000 psi differential under such applications. Other seals, for instance lip seals (V-Ring stack) or O-Rings, are not recommended for service where pr...