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High-pressure, high-temperature (HPHT) well construction operations using cesium formate brine are faster and more effective than those using traditional fluids.

Learning from the experience of others can help you understand the benefits of cesium formate brine. We have categorized operators’ comments from published technical papers and articles describing their experience of cesium formate brine:

  • Major operational success for BP, the first HPHT horizontal well drilled – BP, OTC 15322
  • Cesium formate has a niche application in HPHT wells with open hole completions – Statoil, IADC/SPE 74541
  • Successful drilling of a horizontal HPHT well with a minimum of well control problems – BP, OTC 15322
  • Cesium formate brine system once again demonstrated clear performance benefits such as very low ECDs, moderate to high rates of penetration (ROPs), good hole-cleaning, and excellent wellbore stability while logging – Statoil, SPE/IADC 105773
  • Drilling fluids based on cesium formate brine reduced risk and improved well economics on the Huldra field by: providing extremely good well control, lowering ECDs, increasing trip speed, avoiding surge and swab, reducing time for flow checks, and improving hole cleaning – Statoil, SPE/IADC 105773
  • In addition to being used in the 7 Kvitebjørn wells, cesium/potassium formate brine has been the HPHT completion fluid of choice in all 6 Huldra wells and in 7 Kristin wells – Statoil, SPE/IADC 105773
  • From October 1999 until the present, the preferred workover and suspension fluids used for remedial well operations in these fields have been cesium formate brines – Total, Drilling Contractor, May/June 2007
  • The deployment of this benign brine has greatly reduced the risk of compromising well integrity and well productivity – Total, Drilling Contractor

Endorsements by Category


  • Compatible with cement slurries – Statoil, IADC/SPE 74541
  • 7" liners were run in two Kvitebjørn wells, and successfully cemented in the cesium/potassium formate drilling fluid – Statoil, SPE/IADC 105773
  • The completion strings were run without incidents and good cement bonds were confirmed in both wells – Statoil, SPE/IADC 105773
  • Formate system was seen to be compatible with cement slurries when a casing shoe was squeezed – Statoil, IADC/SPE 74541
  • Very effective casing shoe squeeze on first attempt – Statoil, IADC/SPE 74541
  • No adverse effects on viscosity were seen during compatibility testing – Statoil, IADC/SPE 74541

Clean-up and production

  • There is good compatibility between the mud and production facilities when cleaning up the Kvitebjørn HPHT wells – Statoil, SPE/IADC 105773
  • By the nature of the procedure used to perforate the well large amounts of clear fluid were lost into the formation. Despite this the well cleans up smoothly and quickly – BP, OTC 19242
  • The BHP and BHT indicate that flow was initiated with minimal drawdown and after the initial slow ramp-up the well cleaned up very quickly over an 8 hour period – BP, OTC 19242 


Differential sticking


Economy and operational simplicity

Effect on rig time

Extended reach

Fluid stability

Hole cleaning

Hole stability in sand and shale




Materials compatibility

Rate of penetration (ROP)

Safety, health and environment

Tripping and running equipment

Well control

Well productivity