Detailed Consideration of the Proposed Joslyn Failure Mechanism
Volume 1, Number 1
The Joslyn failure has had a major impact on the licensing of SAGD projects with the Energy Resources Conservation Board. This has had a major impact on the licensing of future SAGD projects. In particular, there seems to be a perception in industry that shallow projects, similar in depth to the Joslyn project, are at risk of failure. While this may seem logical, it really depends on
whether the actual mechanism has been correctly identified(1 ,2). It also overlooks that there have been problems such as shale liquefaction on deeper projects and bitumen communication to surface
on CSS projects that are also deeper. Understanding these failures can’t be stressed enough. If the wrong mechanism is identified, the risk of failure will still exist and future failures may occur.
The author has read a number of applications for commercial projects and there are significant elements from some of these applications that indicate that companies will heavily emphasize
operating pressure as a major driving force, without consideration of thermal expansion. The ERCB has suggested some rules based on frac pressures, which has likely reinforced this perception.
Current applications therefore concentrate on finding the maximum operating pressure. Caprock integrity is also affected by coefficient of thermal expansion, the relative stiffness of the caprock and the reservoir sand, pore pressures, as well the initial stress state that exists over the project.
A number of studies have been done on shallower projects that indicate geomechanical failure should not occur. This includes studies from more than one company and a variety of different
projects. If these simulations are correct, considerable bitumen resources may be recovered. These resources are potentially significant to the Province of Alberta.
The objective of this paper is to review material relating to the Joslyn failure. Some discussion of the implications of the interpretations that have been made are also noted herein.
© 2012 Canadian Energy Technology & Innovation (CETI) Group
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