Swelling layer inflatable

Abstract

An inflatable that features a swelling layer is disclosed. The swelling layer can be made integral or attached to the element or it can be bonded or otherwise secured to the mandrel. Upon inflation with fluid, the element expands into sealing contact with a surrounding tubular or wellbore. The fluid is absorbed or otherwise interacts with the swelling layer so that, in a preferred embodiment, the total occupied volume of the swelling layer and fluid individually is retained after mixing with the swelling of the layer acting to hold the seal of the inflatable element even if a problem develops in the sealing element

Description

PRIORITY INFORMATION [0001] This application claims the benefit of U.S. Provisional Application No. 60 / 525,019 filed Nov. 25, 2003.FIELD OF THE INVENTION [0002] The field of this invention is inflatable packers or bridge plugs and more particularly those that retain a seal after inflation despite an element failure or changes in downhole conditions. BACKGROUND OF THE INVENTION [0003] Inflatable packers typically comprise a flexible element mounted on a mandrel with one stationary collar and one movable collar at an opposite end. Typically a system of valves is used to get pressurized fluid into the annular space between the mandrel and the element to start the inflation process. The inflation allows the element to expand radially into sealing contact with a surrounding tubular or wellbore, made possible by the movable collar riding up toward the stationary collar, which is usually located near the uphole end. The valve system includes a check valve to hold the applied pressure in th...

AI Technical Summary

Benefits of technology

[0008] An inflatable that features a swelling layer is disclosed. The swelling layer can be made integral or attached to the element or it can be bonded or otherwise secured to the mandrel. Upon inflation with fluid, the element expands into sealing contact with a surrounding tubular or wellbore. The fluid is abso

Problems solved by technology

One problem was thermal effects that could cause a pressure reduction under the inflated element and a loss of seal.

Another drawback was that damage to the element either from installation or during service in the well over a period of time could result in a tear or rupture of the element and a loss of seal as the fluid escaped, either slowly or virtually immediately depending on the nature of the failure in the element.

While the valve system had provisions for avoiding overpressure, the risks to the integrity of the element were real and present and resulted in failures.

However introducing cement slurry created several new problems.

First, there were added risks of getting the slurry through the various valves of the inlet assembly without fouling their operation.

Second, the use of cement slurry required specialized equipment at the surface.

Some applications, particularly offshore, created logistical problems in locating such equipment on platforms and created increased expense due to the logistical issues.

As if all these issues were not enough of a concern, there was yet another downside to the use of the cement slurry.

This made the packer more likely to lose its sealing contact after it was set.

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