Industry interest is turning to alternative means of production for the massive reserves located in the Bitumen Region of Canada's Tar Sands. Currently, the region has over 100 installations of sand screens/slotted liners in both injection legs and production legs using Steam-Assisted Gravity Drainage (SAGD) technology. Due to the sensitive nature of the environment, multiple wells must be drilled from a single pad. With the average depths of these wells between 200 and 400 m and lateral lengths between 800 and 1,000 m, a floating sand screen provides assurance that the sand screen will reach the desired depths.
The most typical method of floating the sand screen to bottom uses paraffin to plug the flow access of the screen during installation. In shallow depth wells, the paraffin must be capable of handling differential pressure between the annulus and inside diameter of the screen or liner assembly equivalent to the hydrostatic pressure and any surge pressures encountered during the installation process. The use of paraffin to plug the sand screens currently limits the differential capability to less than 200 psi.
A new technology has been developed that allows for sand screen installations without relying on paraffin wax to withstand differential pressure. This new technology uses a hydro-mechanical valving system incorporated into the screen design to temporarily close off the screen while being run in the hole.
This paper will describe how this technology can provide a reliable, time-saving solution for SAGD installations when floating sand control screens in the hole is required. This solution provides a unique alternative to the methods currently being used to install sand screens with SAGD technology in the rapidly growing Canadian market for bitumen recovery.
A full understanding of sand control requirements in tar sand regions of the world is still needed. Further studies are required as these tar sands are further developed. A failed downhole electrical submersible pump installed in this environment is an initial indication that sand production is an issue. As the need for sand control continues to grow, sand screens are being investigated and used as a sand exclusion device in the producer leg of SAGD twin pairs.
Bitumen regions of the world, specifically Fort McMurray in Canada, require multiple wells on a single pad. These wells range from 200–400 m TVD with 800–1000 m lateral lengths. Installing an open hole completion in to the desired depths under these conditions is very challenging.