Today's conventional sand control screens, such as slotted liner, wire wrap, and premium mesh (both fusion-bonded or "soft-sintered"), retain sand via arrays of single-sized gaps. Although open flow area and mechanical strength differ among such screens, the sand retention mechanism is virtually the same—2 dimensional and gap-based—and performance is sensitive to the particle size distribution (PSD), which is not always well defined or constant along a horizontal wellbore. A very different sand control screen was developed that consists of a ~6 mm thick bed of highly compressed stainless steel wool and is protected by a perforated jacket with about 40% open flow area. The wool fibers criss-cross randomly to create a wide distribution of angular (rhombohedral) pores designed to retain a wide range of PSDs without plugging. Furthermore, this unique, three dimensional filter allows more "harmless fines" to pass, especially during startup, thereby creating an enhanced permeability layer of sand against the screen.
About 1 million feet of this screen has been installed to date (mostly in producers but also in injectors) in a wide range of applications—SAGD, cyclic steam, steam drive, conventional heavy and light oil, gas, gas hydrates, and water producers/injectors—with a remarkably high success rate. Due to its high flow capacity and strength, it has become popular for pump protection and for re-completions inside failed screens. Furthermore, this screen has been successfully replacing gravel packing in certain fields due to its enhanced performance characteristics and lower cost. It has proven attractive for standalone completions in long horizontals where the PSD is either poorly defined or varies significantly from heel to toe.
This paper presents the highlights of recent laboratory testing and field experience that demonstrate the screen's wide range of application, robust characteristics, and unique ability to enhance productivity and handle a wide range of sands with one "gauge". The screen's limitations are also presented.
With today's emphasis on standalone screen (SAS) completions, cost reduction and long horizontals, a presentation of this screen's properties and recent performance is very timely. Furthermore, this screen has recently been combined with inflow control devices (ICDs) to equalize toe-to-heel flux in order to prevent/delay water/gas coning and also minimize watercut if/when water eventually migrates to the wellbore.