High pressure sealing system with automatic pressure relief (18-Aug-2009)
The high pressure sealing system comprises two or more packers placed with a predefined distance between them. The sealing element reacts to the well fluid and swells radially outward to seal the annulus between the tubing and cased-hole or open-hole wellbore. A differential pressure limiter is placed in a passageway through at least one of the packers. The system will be exposed to differential pressure after the sealing element has sealed the annulus. The differential pressure limiter opens at a pre-set differential pressure value to reduce the differential pressure across at least one of the sealing elements. In a system built with two packers pressure between the packers will increase to a value between the pressure on one side and on the other side of the overall system, Thus, the differential pressure across each of the two packer elements will be controlled and be lower than the over differential pressure across the system.. At a pre-defined value of differential pressure over the first packer the limiter closes. The pre-defined value of the differential pressure limiter is set to a pressure that is below the failure pressure of the packer element. By adding more packers with differential pressure limiters it is possible to achieve a differential pressure capacity over the total system that will exceed the limits of the single packer(s) without risk of failing each one.
014046; 017394
Title:
High pressure sealing system with automatic pressure relief
Abstract:
The high pressure sealing system comprises two or more packers placed with a predefined distance between them. The sealing element reacts to the well fluid and swells radially outward to seal the annulus between the tubing and cased-hole or open-hole wellbore. A differential pressure limiter is placed in a passageway through at least one of the packers. The system will be exposed to differential pressure after the sealing element has sealed the annulus. The differential pressure limiter opens at a pre- set differential pressure value to reduce the differential pressure across at least one of the sealing elements. In a system built with two packers pressure between the packers will increase to a value between the pressure on one side and on the other side of the overall system, Thus, the differential pressure across each of the two packer elements will be controlled and be lower than the over differential pressure across the system.. At a pre-defined value of differential pressure over the first packer the limiter closes.
The pre-defined value of the differential pressure limiter is set to a pressure that is below the failure pressure of the packer element. By adding more packers with differential pressure limiters it is possible to achieve a differential pressure capacity over the total system that will exceed the limits of the single packer(s) without risk of failing each one.
Description:
The high pressure sealing system with automatic pressure relief is a cost effective method to achieve high differential pressure rating of a packer system with multiple packers. The packer system is used in oil field application to isolate one or multiple zones of the well. The system contains two or more packers placed in the proximity of each other onto the casing or liner, or onto production tubing in an open hole wellbore.
Each packer comprises the following:
- two anti extrusion rings
- rubber sealing element
- one or more differential pressure limiter systems
The anti extrusion rings will protect the packer during RIH and provides a long term functionality of the sealing element.
In one example embodiment, the sealing elements are made of swellable rubber. The rubber sealing element will swell in the activating fluid for example and not limited to crude, hydrocarbon gas, CO2,
water, water vapour, water and oil based mud. The activating fluid could either be present in the wellbore, or be integrated into the swellable element or adjacent assembly. The sealing element can either be bonded to the tubing or slide onto the tubing. The rubber sealing element can consist of solid and/or reinforced rubber.
In other example embodiments, the sealing elements could be inflatable packer elements, or conventional compression set pa...
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