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A Further Look At The Impacts Of Corrosion Inhibitor On Scale Prevention

Scale and corrosion inhibitors are commonly used in many oil and gas production systems to prevent inorganic deposition and to protect asset integrity. Scale inhibitor products are based on organic compounds with phosphate or carboxylic functional groups such as amino phosphonates, phosphate esters, phosphino polymers, polycarboxylate and polysulfonates,1 as shown in Figure 1. These anionic groups have strong affinity to alkaline earth cations and can adsorb on the active growth sites of scale crystal (Figure 2), resulting in stopping or delaying the scale formation process.

Product Number: 51322-17676-SG
Author: Qiwei Wang, Tao Chen, Hameed Al-Badairy, Sultan Alsubaie, Yasser Al-Jeshi, Mohammad Alsidan
Publication Date: 2022
$20.00
$20.00
$20.00

In the previous work (paper C2021-16736), we presented the results on calcium carbonate deposition and inhibition in the presence of 50 ppm of corrosion inhibitors. Further studies were performed to investigate the influence of three corrosion inhibitors at high concentrations on calcium carbonate formation and the performance of scale inhibitors, to simulate the conditions where high corrosion inhibitor dosages are applied or during the early flow back stage after batch treatment.

The active ingredients are, respectively, quaternary ammonium, phosphate ester and fatty acid; imidazoline acetate and ethoxylated fatty amine; and quaternary ammonium compounds, in the three corrosion inhibitors. Scale inhibitors are based on polyacrylate, ATMP phosphonate, and DETPMP phosphonate. Tests were conducted at 85 oC using the dynamic tube blocking method and test brine was characterized with high TDS (~ 65,000 mg/L) and high calcium (~ 4,000 mg/L). Change in scale deposition rate was used to assess the corrosion inhibitor impact. Contrary to the reported findings with barium sulfate scale, results from this study showed that even with 500 ppm corrosion inhibitors, no noticeable decreases in scale inhibitor performance were observed. Instead, the corrosion inhibitor based on imidazoline acetate and ethoxylated fatty amine prevented calcium carbonate scale deposition entirely without scale inhibitor. Additional tests also showed that this corrosion inhibitor had a significant impact on the morphology of calcium carbonate scale precipitates.

In the previous work (paper C2021-16736), we presented the results on calcium carbonate deposition and inhibition in the presence of 50 ppm of corrosion inhibitors. Further studies were performed to investigate the influence of three corrosion inhibitors at high concentrations on calcium carbonate formation and the performance of scale inhibitors, to simulate the conditions where high corrosion inhibitor dosages are applied or during the early flow back stage after batch treatment.

The active ingredients are, respectively, quaternary ammonium, phosphate ester and fatty acid; imidazoline acetate and ethoxylated fatty amine; and quaternary ammonium compounds, in the three corrosion inhibitors. Scale inhibitors are based on polyacrylate, ATMP phosphonate, and DETPMP phosphonate. Tests were conducted at 85 oC using the dynamic tube blocking method and test brine was characterized with high TDS (~ 65,000 mg/L) and high calcium (~ 4,000 mg/L). Change in scale deposition rate was used to assess the corrosion inhibitor impact. Contrary to the reported findings with barium sulfate scale, results from this study showed that even with 500 ppm corrosion inhibitors, no noticeable decreases in scale inhibitor performance were observed. Instead, the corrosion inhibitor based on imidazoline acetate and ethoxylated fatty amine prevented calcium carbonate scale deposition entirely without scale inhibitor. Additional tests also showed that this corrosion inhibitor had a significant impact on the morphology of calcium carbonate scale precipitates.