Formate fluids calculators go online

Aberdeen, Scotland – 09 September 2023
DensiCalc™ uses field-validated PVT data to calculate downhole densities and pressures for all formate fluids.

All three of Sinomine Specialty Fluids’ formate fluids calculators are now available online from this website. BufferCalc™ – the new software that determines buffer concentrations for formate fluids – is added to DensiCalc™ and PVTCalc™, which calculate fluid densities, downhole pressures and PVT data. All are free to use and only available from us.

Siv Howard says: “We’ve used our considerable experience of formate fluids, built up over nearly 25 years, to develop and perfect DensiCalc™, PVTCalc™ and BufferCalc™. By bringing these calculators online, we’ve made them easier to access and use. We also plan to launch an app containing all three calculators later this year.”


DensiCalc™ calculates downhole densities and pressures for the entire formate fluid density range from 1.01 to 2.30 g/cm3 (8.34 to 19.20 lb/gal). The software utilises laboratory-measured PVT data, which have been field-validated by PLT logs and surface-density readings to establish:

  • Average brine density over the length of the wellbore
  • Riser margin (if offshore)
  • Pressure and temperature at user-selected points in the wellbore
  • Pressure exerted at sea-floor level by the brine column in the riser (if offshore)
  • Brine density at standard (15.6°C/60°F) and user-defined temperature conditions

You can work with up to five wells simultaneously, saving data for future reference if necessary. Click here to use the calculator.


PVTCalc™ calculates density, thermal expansion coefficient and compressibility under actual downhole pressure and temperature conditions for formate fluids. PVTCalc™ is unique for formate fluids and is based on laboratory PVT measurements.

The software is valid for potassium formate brines in densities of 1.00 to 1.57 g/cm³ (8.34 to 13.1 lb/gal), blends of cesium and potassium formate brines in the range of 1.57 to 2.20 g/cm³ (13.1 to 18.4 lb/gal), and cesium formate brine for densities of 2.20 to 2.30 g/cm3 (18.4 to 19.2 lb/gal). Properties are extrapolated for temperatures up to 250°C (482°F) and pressures up to 2,068 bar (30,000 psi). Click here to use the calculator.

Results from extensive laboratory testing form the basis for PVTCalc™.


As the standard API alkalinity test method is unsuitable for determining carbonate and bicarbonate concentrations in formate fluids, we have perfected our own solution. This simple method, which has been adapted by the ISO, uses comprehensive laboratory data to calculate carbonate and bicarbonate concentrations in formate brines and only requires a pH measurement, a possible pH adjustment and a phenolphthalein titration. As the method requires a series of bespoke calculations, we have created our own calculator, which performs all calculations in accordance with ISO 13503-3:2022. Click here to use the calculator.

BufferCalc™ combines comprehensive laboratory data and over 20 years’ field experience to measure carbonate/bicarbonate concentration in formate fluids.

To learn more about formate fluids’ densities and pressures, PVT data and buffer concentrations, please download sections A2, A6 and C2 of our Formate Technical Manual.