How Do Expandables Work?

While expandable metals have been used in numerous industries for years, the oil and gas industry has just started tapping this technology within the last decade. Expandables are now being used in the oil field in both drilling and production applications, and more studies are ongoing to discover how expandables can be used in completion processes in the future.

EXPatch Expandable Cladding SystemSource: Baker Hughes

While a well does not usually employ expandables, the expanding tubular can be used to overcome a number of problems that may occur after the well has been drilled. Expandable tubulars are used in the oil field to increase the diameter of the casing or liner within a well -- after it is downhole.

In both drilling or completion applications, the expandable tubular is deployed within the well to an exact location and extended using hydraulic force. Unlike other solutions, expandables do not restrict the diameter of the wellbore, eliminating any chance of decreasing the completion size of the well.

During drilling operations, expandable liners can be employed on casing strings to warden off problem zones and allow drilling to continue by stopping fluid loss from depleted areas. Also, expandables can be used during drilling to extend the diameter of the well within the reservoir and increase production rates.

Sometimes after casing a well, the casing can become damaged, and the well can fall in upon itself, and halt production. Many times expandables are used to repair worn casings, upgrade them or close perforations that need to be completed again. Used in both open-hole and cased-hole wells, these types of expandables are used to isolate a section of the well and overcome some issue, such as improving water control or sand control within the well.

Expandable tubulars are available in both custom-fit and variable sizes that can be formed to fit the wellbore. While the using expandables on wellbores is somewhat novel, the technology has been used successfully in oil wells worldwide.