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Unformatted text preview: 7 V. Conclusions on Well Design, Cementing, and Flow Path A. Cause of the Failure of the Cement Barrier Contamination or displacement of the shoe track cement, or nitrogen breakout or migration, could have caused the shoe track cement barrier to fail. The Panel found evidence that the most likely reason the shoe track cement slurry failed is due to contamination in the rat hole portion of the wellbore and inversion of fluids due to different densities (the mud in the shoe track was lighter than the unfoamed cement slurry). However, the Panel could not definitely rule out nitrogen breakout, migration, or over‐displacement in the shoe track. The Panel concluded that a combination of contamination, over‐
displacement, and/or possibly nitrogen breakout of the shoe cement were causes of the blowout. Contamination of the foamed cement in the annulus by the mud, base oil or cement spacer could have resulted in nitrogen breakout, leading to a failure to achieve zonal isolation of hydrocarbons in the annulus. The Panel concluded, bas...
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