Oil and gas production field requirements to maintain asset integrity and scale control are very diverse. In an operator’s field in Latin America, the conditions across several wells required the co-injection of corrosion and scale inhibitors. The brine composition of these wells is challenging due to relatively high concentration of calcium ions as well as the presence of iron. The selected scale and corrosion inhibitors need to be compatible with brine and with each other without negatively impacting the absolute performance of the individual products. An additional practical challenge for product selection was imposed by the extreme remote location of the field requiring the product to perform at an optimal dosage without increased transportation and logistics costs.
This paper describes the results from screening studies conducted with a series of corrosion inhibitor product formulations using different static and dynamic lab performance evaluation test methods. As the primary corrosion inhibitor actives are oil-soluble by nature, focus was given to formulating the product with an appropriate selection of solvents, such as methanol and isopropanol, and surfactants to achieve the desired compatibility with the brine and scale inhibitors. The final products were identified, and an optimal product dosage was arrived at based on tests conducted under typical and aggressive conditions representative of the field. However, due to the diversity of conditions and corrosion severity levels across multiple wells in this field, corrosion prediction simulations were run for unmonitored wells to estimate a baseline corrosion rate and build confidence in the recommended corrosion inhibitor product dosage. The validation of the prediction for monitored wells with ER probes will also be discussed in this study.