Abstract

Expandable technology is capturing the imagination of the oil & gas industry because of its ability to significantly reduce well costs whilst improving well functionality and performance. This paper will describe the fundamentals of pipe expansion, the differing types of expandable tubes and the evolution of the Technology from the first laboratory trials, through the early field tests and into commerciality. Barriers to entry of new technologies are discussed, together with the importance of Operator involvement. Milestone product developments are described and are supported by field trial information. Both expandable drilling liners, expandable sand screens, expandable casing cladding systems and expandable liner hangers are discussed. The final section of this paper will look forward with a reasoned view on the potential state of the technology within the next 5 years.

Introduction-

The development of technology within the oil & gas business has simple drivers and is related almost directly to the maturity of the oil & gas business itself.

As the world's reserves portfolio ages, the effort required to find, develop and produce our reserves is increasing. This would result in increasing costs and without new technology, the costs of producing would make hydrocarbon products uneconomic. Cost reduction is therefore the major driving force behind technology development. Expandable technology is seen as a means of reducing the overall cost of a well and its support infrastructure. The application of the technology within the first ten years has been aimed mainly at those wellbore construction techniques that have remained unchanged for decades.

Telescoping casing designs have existed since the very first wells and reservoir completion practices have remained stagnant, dominated by gravel packing. The basic design of liner hangers, packers and through tubing straddles has not changed either; expandable technology will, and already has revolutionized techniques in these areas.

Whilst the "reforming" of pipe has been commonplace within in the industry for decades, notable activities including the swedging out of collapsed casing and the setting of thin walled casing patches, these do not classify as expandables under the term used today; The increase in circumference of a cylindrical pipe downhole, achieved through a wall thinning process and resulting in a cold working of the material through plastic deformation, was championed in the early 1990's by Shell International research staff. Shell's vision for the technology was also driven by the desire to reduce costs-by reducing the quantities of consumables used to construct the well. They reasoned that reducing the telescopic nature of a conventional casing design would allow a much smaller surface casing to be used and each subsequent casing could be reduced in diameter. Tangible savings are reduced drill cuttings, reduced mud volumes (& waste), with reduced steel, cement and chemical consumption.

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