BSI was contracted to eliminate gas migration on the backside of the 7” casing of a well being plugged in Pennsylvania. Bond logs indicated good cement, so a noise-temp log was used to identify the shallowest gas source (600’). 3 sand notches were cut 1’ apart just above the source, a plug was set below the notches, 2-3/8” tubing was placed just below the bottom notch, and a packer was set above to isolate the notches.
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 600 psi before dropping to around 400 psi when injection increased to 1.270 gpm. This breakthrough allowed a significant amount of fluids to be injected at the end of the 1st stage, which carried over to the beginning of the 2nd stage, where 2 additional breakthroughs were achieved. Injection decreased steadily throughout the 2nd stage and continued to do so across the next 8 stages.
The flow rate began at 1.270 gpm in the 1st stage and ended at 0.011 gpm at the conclusion of the final stage, with a total of 61.9 gal injected. This constituted a 99.1% decrease in injectivity, implying significant formation of calcium carbonate in leakage pathways.
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