Development and Testing of a Viable Alternative to Horizontal Gravel Packing: An Expandable Sand Screen and Expansion Tool
Authors: Echols Ralph , Gano John , Shy Perry , Tuckness Cindy , Zhang Haoyue , Campo Don 
Published: October 2008

Abstract
A new technology recently introduced to the oilfield-expandable-sand-screens-has focused on providing solutions for the inherent weaknesses in traditional sandcontrol completion techniques that can affect borehole stabilization, production rate, and completion costs. Gravelpack operations can also increase logistical requirements, and in many wellbore scenarios, can be difficult to perform. Finally, stand-alone screen completions are subject to borehole collapse. This problem can lead to sand production and screen-erosion during production.
This paper will review a new expandable sand screen system that has the capability to provide a solution for some of the inherent problems discussed above. The discussion will focus on 1) the development of the technology required to expand perforated pipe plastically, 2) the tools and techniques employed, 3) the development of the screen, 4) the testing results, and 5) the first field trial of system.
The innovative sand screen system provides the capability for the screen to be expanded against the borehole ID. The annulus around the screen is then virtually eliminated, which in turn, eliminates the need for gravel packing. Also, this increases the sand screen surface area, thus reducing pressure drop across the filter and increasing production rates. Because of its high strength, the expanded screen can provide superior support to stabilize the borehole, which then minimizes the potential for sand production. Finally, the new screen provides a larger production ID than is normally possible with traditional screens.

Introduction
Well screens are used in the openhole-producing zone of a horizontal well to provide filtration to prevent sand production.1,2,3,4 After the well has been on production for a period of time, the formation can become somewhat unstable. This condition can result in excess sand production and holesloughing, which can cause plugging and subsequent erosion of the screens. In some cases, significant external loads can be applied to the screen as a result of wellbore collapse. These external loads can collapse the screen if it does not have sufficient structural integrity. To provide the best level of sand control and wellbore support, the annular space between the screens and wellbore can be gravel packed. However, to create a reliable horizontal gravel pack completion with a high probability of success is difficult in some well conditions.5,6,7,8,9,10 Also, the installation of a sand-control screen reduces the production ID that is otherwise available, and designing for gravel pack placement around the screen can reduce the ID still further.
An expandable filtration system with enhanced collapsestrength integrity was chosen as the appropriate solution for this problem. If this system could be successfully developed, the following measurable results would be realized:Reduced failure rate due to elimination of hot spots (erosion) over timeIncreased hole size for re-entry and work-over capabilitiesIncreased production ratesPossible reduction in bore size for drilling-cost reductionImproved reliability due to greater installation successInstalled cost comparable to horizontal gravel packed wells.