ABSTRACT
Questions concerning acid inhibitor effectiveness at high velocities and in the oxygen rich environments common to Coiled Tubing (CT) applications prompted laboratory testing of several acid inhibitors at various concentrations in common acid stimulation fluids.
Following the laboratory testing, special CT nozzles were manufactured to position standard corrosion coupons in the direct path of the stimulation fluid flow as it exited the CT during acid treatments. The data gathered from the corrosion coupons were used to validate the laboratory tests.
As a result of these studies, unnecessarily high acid inhibitor volumes and undesirable or even potentially hazardous field practices were discontinued. The information learned from the studies was incorporated into field practices, which resulted in safer, lower risk operations, reduced the chance of formation damage, and lowered the overall operating costs for acid stimulation treatments.
This paper documents the testing and results of the lab and field studies. In addition, the nozzles described in this paper provide an easily implemented and inexpensive quality control tool for CT acid work in virtually any area CT stimulations are performed.
