Expandable sand screens (ESS®) are a relatively new sand control system, which combines many of the properties of gravel packs with the ease of installation of a stand-alone screen. Although they have been used in a wide variety of applications, they are not considered a panacea and have an operational envelope, which is becoming clearer with time.

Weatherford's ESS system currently (June 2005) has 340 installations and over 700 years of combined production. A recent survey of the installations was analyzed in terms of performance and reliability.

The productivity performance of the ESS has been shown to be very good, with an average skin of 0.3 being achieved in recent openhole applications. ESS completions generally perform better than the baseline models. Where field comparisons were possible, they also performed better than alternative sand control completions.

Over the 340 ESS wells, ESS has a reliability comparable with other sand control systems, with initial failures less than 5% and a production failure rate of 0.021 failures/well.year. This gives a projected survival rate at 20 years of greater than 90%. This rate is expected to get better with improving operations, designs, systems and application selection.

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