BSI was contracted to seal a leak in the 7” x 4-1/2” annulus on a well in Pennsylvania. An acoustic log identified the source of the leak was at around 2,000’. The well was prepared by setting a bridge plug at 2,000’, cutting three narrow sand notches through the 4-1/2” casing just above the plug, installing 2-3/8” tubing to the depth of the bottom notch, and setting a packer just above the top notch.
Five injection stages were run over a 36-hour period.
Pressure was gradually increased in the 1st stage and brough up to 1,475 psi 30 min into pumping. Pressure was held steady for the next 100 min while flow rate held steady. Pressure was quickly brought up to 1,350 psi in the 2nd stage while flow rate fell steadily. This same trend continued through the conclusion of the 3rd stage. The well was then shut in at pressure overnight, which allowed calcium carbonate crystals to form.
Injection resumed the next morning at 1,475 psi. The flow rate was significantly lower than in the previous stage, implying substantial crystal growth overnight. The flow rate continued to fall across the final two stages and the well was shut in again after pumping.
The flow rate began at 0.910 gpm in the 1st stage and ended at 0.010 gpm at the conclusion of the 5th stage, with a total of 135 gal injected. This constituted a 98.9% decrease in injectivity, implying significant sealing.
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