There are number of downhole applications for the corrosion inhibition
- Acid stimulation -tubing inhibition
Stainless steel has been used successfully in H2S and CO2 corrosion while is susceptible to HCl attack. Hydrochloric acid is widely used in oil and gas production to stimulate the formation. The corrosion inhibitor need to sustain high temperature in downhole (up to 200°C). Amide type of corrosion inhibitor may perform at temperature up to 200°C. Nitrogen quaternaries compounds showed good corrosion resistance with 15% HCl.
- Scale removal by acids inhibition
acids injected downhole for scale removal are extremely corrosion to production tubing and casing liners. inhibitors are added to acid solution to minimise the corrosion. the selection of corrosion inhibitors should screen tested based on the acid of the application and tubing materials.
Side Effect of downhole corrosion inhibition
- Emulsify the oil/water
- HCl in stimulation solution will reacts with alcohols to increase the corrosivity of the fluid
- may adversely impair the effect of gas hydrate control chemicals
– Johannes Karl Fink Petroleum Engineer’s Guide to Oil Field Chemicals and Fluids, 2012 Gulf Professional Publishing