The effectiveness of a permanent abandonment plug is measured by its ability to bridge the wellbore cross section both vertically and horizontally, including all annuli, with a plugging medium which can withstand the rigors of the environment to which it is exposed (Figure 1 – Barrier Requirements). The most common method for placing a plug in cased hole with an uncemented annulus has required section milling of the casing, making a clean out run and underreaming of the open hole prior to placing a balanced cement plug. A new method is presented which creates a permanent abandonment plug through the use of a system which perforates uncemented casing, washes the annular space and then mechanically places the cement across the wellbore cross section in a single run. This paper outlines the design methods, laboratory testing and operational elements that were assessed during the development phase, as well as the results of field trials used to qualify this technique.

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