Bottom Hole Temperature


  • Calculates Bottom Hole Static Temperature (BHST) or Temperature Gradient (TG)
  • Predicts Bottom Hole Circulating Temperature (BHCT)
  • Supports US and Metric units
  • Utilizes methodologies and data found in API Recommended Practice 10B-2 Second Edition, April 2013


  • True Vertical Depth (1000 to 22000 ft and 300 to 6600 m)
  • Measured Depth (>= True Vertical Depth)
  • Temperature Gradient (0.7 to 1.9 °F/100ft and 1.60 to 3.60 °C/100m)
  • Bottom Hole Static Temperature (87 to 498 °F and 32 to 264 °C)


  • Bottom Hole Static Temperature (°F and °C)
  • Bottom Hole Circulating Temperature (°F and °C)
  • Temperature Gradient (°F/100ft and °C/100m)


The bottom hole temperatures and bottom hole circulating temperatures affect every aspect of the well. An accurate determination of the bottom hole temperature at various depths is critical to the effective drilling, cementing, stimulation and production of the well.

API Bottom Hole Static Temperature (BHST) and Bottom Hole Circulating Temperature (BHCT) is used by engineers and professionals in:

CO2 and N2
Coil Tubing
Drilling Muds
Fluid Mechanics
​Fracturing Fluid
Well Production
Wellbore Mechanics
Laboratory Analysis​
Oil and Gas Industry
Petroleum Industry​

API Bottom Hole Static Temperature (BHST) and Bottom Hole Circulating Temperature (BHCT) at a given depth can be used to determine:

Acid, Cement, Fracturing, and Production, fluid flow models by determining the viscosity of the fluids at BHST’s used in various modeling and design programs ( i.e. N’, K’, friction).
Cement slurry properties for Casing, Liner and Squeeze cements at BHST and BHCT.
Cement Total Thickening Times, Fluid Loss, Free Water, and Rheological Properties at BHCT.
Cement compressive strength and settling tendencies at BHST.
Cement spacers and drilling muds rheological properties and compatibility of at BHCT.
Drilling mud rheological properties such as plastic viscosity, yield point, etc., and fluid loss at BHST’s at various depths.
Fracture fluid breaker tests to develop appropriate additive types and concentrations at BHST.
Rheological properties of fluids pumped through coil tubing at BHST for friction calculations.
Rheological properties of fluids containing CO2 at BHST.
Tubing Stretch or contraction due to static and dynamic fluid temperatures (BHST and BHCT).
Others properties where bottom hole temperatures are need for analysis or modeling.​​


The tables in Annex D of API RP 10B-2 are a matrix of predicted circulating temperatures for the following well simulation schedules as a function of true vertical depth and temperature gradient.

  • Casing
  • Liner
  • Squeeze

Temperature predictions are given for true vertical depths ranging from 1,000 ft to 22,000 ft and temperature gradients ranging from 0.9 to 1.9.

To predict bottom hole temperatures, BHT utilizes a standard regression technique. This technique, when used in combination with cited tables in API RP 10B-2 Annex D, allows BHT to predict bottom hole temperatures for any depth-gradient input combination that fall within the bounds of relevant tables.

Smaller temperature gradients than those listed in Annex D have been extrapolated from 0.9 °F/100 ft down to 0.7 °F/100 ft in response to a customer request. Temperature predictions for this gradient range utilize the same regression technique referenced to above.

If the user-defined measured depth value is greater than true vertical depth by 1,000 ft or more, the well is assumed to be highly deviated, lateral, or horizontal and the predicted bottom hole circulation temperature is set equivalent to the bottom hole static temperature value.


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