Pressure responsive centralizer

Abstract

A centralizer including hollow structural components. In at least one embodiment, the hollow structural component is sealed by at least one valve or rupture disk. When unacceptable overpressures occur, the valve or rupture disks break to allow influx into the hollow element, thereby relieving pressure and avoiding damage that might otherwise occur. In other embodiments, the hollow structural component collapses to expand available volume.

Description

FIELD OF THE INVENTION [0001] The present invention relates to systems and methods for controlling pressure in wellbores. BACKGROUND AND SUMMARY OF THE INVENTION Background: Pressure in Well [0002] Annular pressure buildup within wellbores has been recognized in the oil and gas industry for many years as a serious problem. Fluids trapped in a wellbore or annular space in a wellbore will expand with a corresponding increase in temperature leading to a volume increase and increase in the force they exert upon the surrounding area. This pressure has been known to be a significant factor in the failure of subsea wells, including Well A-2 of British Petroleum 1999 Marlin development program in the deepwater program off the Gulf of Mexico. One relevant article is Practical and Successful Prevention of Annular Pressure Buildup on the Marlin Project, SPE International 77473, 2002, Richard F. Vargo, Jr., et al, and which is hereby incorporated by reference in its entirety. Background: Annula...

AI Technical Summary

Benefits of technology

[0016] A final way of mitigating APB is by using enhanced casing products. Increased casing capacities can accommodate a higher degree of pressure buildup without detrimental effects to the casing or well. Extensive work has been applied here also involving advanced, probabilistic performance properties of the subject casings. Pressure Responsive Centralizer System

[0017] The present inventions describe methods and systems for controlling pressure and volume variations in boreholes. For example, in one embodiment an innovative centralizer comprises a centralizing structure with at least one sealed hollow structural component where a rupture disk is capable of breaking in response to sufficient pressure. The present innovations further teach a method of effecting a volumetric change in response to overpressure within a wellbore comprising at least one hollow structural component. The present innovative systems and methods can be used to avoid production loss due to wellbore damage or the need to restrict hydrocarbon flow in an effort to keep production temperature below danger levels.

Problems solved by technology

Annular pressure buildup within wellbores has been recognized in the oil and gas industry for many years as a serious problem.

This pressure has been known to be a significant factor in the failure of subsea wells, including Well A-2 of British Petroleum 1999 Marlin development program in the deepwater program off the Gulf of Mexico.

When wellbore fluids heat up and expand in a closed system, the expansion causes high induced pressures.

Consequently, bleeding the outer annuli may not be possible.

Second, a temperature rise is generally associated with the increase in pressure.

However, cement can still channel because of poor mud displacement.

Such displacement problems are caused by poor casing eccentricity or poor erodibility of the wellbore fluids during the primary cementing operation.

In addition, barite sag following drilling can cause a trapped condition.

This collapse results in a correspondent increase in available volume to thereby decrease pressure.

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