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Alternate path shroud with erosion resistant perforations Disclosure Number: IPCOM000226572D
Publication Date: 2013-Apr-16
Document File: 2 page(s) / 101K

Publishing Venue

The Prior Art Database


This defensive publication describes an improved CAPS system, which utilizes a shroud instead of a base pipe and erosion resistant perforations. Instead of a full basepipe, a thinner shroud would allow decreased material costs, easier manufacturing, and easier rig floor assembly. Methods of connecting the shroud from screen joint to screen joint become simpler because crimping and other options are more readily available.

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Alternate path shroud with erosion resistant perforations

Gravel packing around sand screens has become a common method of filtering formation fines for many years.  Gravel packing is filling the void area between the screen and open hole with a prepared gravel.  This prepared gravel is typically consistent in size and shape and its properties are selected to best suit the particular reservoir.  The placed gravel filters finer formation sand and is filtered itself by a sand screen.

Sometimes, problems prevent a complete pack.  These problems include: rat holes or high washout areas, collapsed formation, high leak off to the formation.  An incomplete gravel pack can lead to “hot spots” or high velocity flow areas where the gravel is not present.  Hot spots can be quite damaging to a sand screen and over time can erode a hole in the screen, allowing formation fine sand to be produced.  This can damage other well equipment and potential cause a loss of the well.

Alternate path systems have been developed to help mitigate voids in gravel packs.  They do this by providing an alternate path for the sand slurry to flow when the gravel pack is placed.  If a problem area occurs which normally would have prevent sand progression, the alternate path system provides a secondary route of flow for the slurry to travel and bypass the problem area.  The slurry travels through the secondary route and fills in remaining void areas.

Several variations of alternate path systems have been developed and tested over the years.  Shunt tube systems utilize a tubing system mounted outside the sand screen as the secondary flow path for slurry.  Shunt tube systems have been lab tested and field proven with many installations in the past twenty years.

CAPS, or concentric annular pack screen, is another type of alternate path system developed by Halliburton.  CAPS uses a perforated base pipe mounted over the sand screen to create an additional annulus region within the borehole.  Slurry has two annulus regions to travel through: 1. Outside the CAPS perf...