There are free spreadsheets available at the websites below that calculate the corrosion rate steel in an environment that contains CO2. A portion of each of these spreadsheets is the calculation of pH and HCO3- as a function of temperatureand CO2 partial pressure. You could trial and error the CO2 levels to find your pH to reverse the process and get the alkalinity/bicarbonate level. In the case of the NORSOK spreadsheet, make certain that you select the "formation water" option to avoid calculations that only apply to pure water with no dissolved salts. Finally, both of these spreadsheets require you to run either as an Excel add-in or macro. Either of these situations usually requires you to enable an Excel feature that is usually turned off for security purposes.

http://www.corrosioncenter.ohiou.edu/software/freecorp/

https://www.standard.no/en/sectors/energi-og-klima/petroleum/norsok-standard-categories/m-material/m-5061/

Hi Deepti,

If you can use the equations which describe the levels of carbonate and bicarbonate in water in function of CO2 partial pressure above the water solution, the check out the added paper on this topic. It gives a full description of the problem area and its solutions.

Have fun.

Frank