## 2 Experimental Development
### Electrochemical Tests in Corrosion Loop
**Zone 1** indicates how long the inhibitor takes to coat the graduated cylinder. The steeper the slope, the greater the coating speed and, thus, the better the inhibitor's performance. **Zone 2** shows the moment in which the inhibitor starts to work; the corrosion rate was 0.94 mm/year with an imbalance rate of 0.22, which is a high corrosion rate according to [PERSON] et al. [57] with no pitting. **Zone 3** indicates the moment in which the inhibitor stops working, and in this zone, the corrosion values increased sharply. It is important to point out that the corrosion inhibitor was added only once for each test. Figure 4 corresponding to Inhibitors 2, 3, and 4, show that the **zone** differentiation was not as clear as it was for Inhibitor 1. For these cases, both the corrosion rates and the imbalance rates remained high; in addition, in the worst-case scenario, slopes are positive, as is the case for Inhibitors 3 and 4 (Figure 5), showing the presence of pitting. In the studies carried out with the rotating cylinder for Inhibitors 2, 3, and 4, efficiency was under 90% with the presence of pitting. Observing the performance of Inhibitor 1 in Figure 4, it can be stated that the corrosion rate was 0.94 mm/year, when the inhibitor was working, whereas the data obtained in Table 3 indicate the average of all the tests, that is, the values obtained with and without the inhibitor working. Figure 6: Different zones in which the inhibitor works. Zone 1: the time the inhibitor takes to coat the graduated cylinder and inhibit. Zone 2: the period during which the inhibitor works. Zone 3: the period in which the inhibitor stops working, and the corrosion rate increases. [PERSON] et al. [41] precisely measured the wall shear stress under controlled laboratory conditions, under a single-phase tap-water flow in a wide range of gas-liquid flow regimes (stratified flow, slug flow, and annular mist flow). The highest wall shear stress measured was of the order of \(10^{2}\) Pa in an atmospheric pressure flow system. Atomic force microscopy measurements indicated that the forces of the order of \(10^{7}\) Pa would be required to remove an iron carbonate precipitate from a mild steel surface. They concluded that this is an important finding indicating that the wall shear stress typically seen in multiphase flow lines is not sufficient to damage FeCO\({}_{3}\) layers, which could lead to accelerated and localized corrosion. Although [PERSON] et al., obtained important results, these are purely mechanical, and neither electrochemical phenomena nor the physical mechanisms of the solid (such as the doping of FeCO\({}_{3}\) crystals with Na\({}^{+}\), Ca\({}^{2+}\), ions, etc.) were considered between the protective layer and the medium (reservoir water containing high salt concentration). The studies of [PERSON] et al. [36] show a comparison of the corrosion rate for FL and RCE tests obtained under the same conditions of 1 bar CO\({}_{2}\), 50 \({}^{\circ}\)C, 20 Pa shear stress in the Forties formation water, with pH 5.6. [PERSON] concluded that this comparison was not good because the mass transfer was lower for the RCE test than for the FL under the same shear stress [37; 38; 39; 40; 41]. Therefore, in accordance with [PERSON]'s perspective, we should not compare the results obtained herein for FL and RCE tests. However, the difference lies in the fact that both methods complement each other, given that the fluid rate conditions, and not those of the shear stress, were maintained for both methods. After using RCE to determine which inhibitor had a general corrosion inhibition capacity greater than 90%, under the same operating conditions, the properties of FL were reassessed under conditions more similar to what actually occurs in the field, obtaining the moment in which the protective layer was formed, the moment in which the inhibitor began to be effective, and the moment in which it started to lose its anti-corrosion capacity (Figure 6).