BSI was contracted to mitigate casing pressure on a well being plugged in Pennsylvania. Bond logs showed poor cement bonding throughout the well and an unsuccessful attempt to pull the 4-1/2” casing was made. The well was prepared by cutting three sand notches around 500’ through the 4-1/2” and 9-5/8” casing strings, a bridge plug was set 1’ below the bottom notch, and 2-3/8” tubing was installed to the depth of the bottom notch.
Our team arrived on site and began injecting our fluid system. 10 injection stages were then run over a 48 hour period. At the conclusion of each stage pressure falloff was measured to evaluate progress.
Pressure was stepped up incrementally in the 1st stage to 700 psi, with very little injection achieved. This held true for the next two stages and the well was shut in at pressure overnight after the conclusion of the 3rd stage. A breakthrough occurred at the beginning of the 4th stage, which allowed a significant amount of fluids to be injected. The flow rate remained high over the course of the next two stages before decreasing steadily across the final four stages.
The flow rate began at 0.530 gpm in the 1st stage and ended at 0.002 gpm at the conclusion of the final stage, with a total of 191 gal injected. This constituted a 99.6% decrease in injectivity, implying significant formation of calcium carbonate in leakage pathways.
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