Formation Temperature Calculator
Calculate geothermal gradient and formation temperature at any depth using surface temperature and bottom-hole temperature data.
Well Temperature Data
Tdepth = Tsurface + G × Depth | G = (BHT − Tsurface) / TD
Geothermal Gradient
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Temp at Target Depth
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Temp at TD
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Surface Temp
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Temperature vs. Depth Profile
How this was calculated
Geothermal gradient: G = (BHT - T_surface) / TD. Expressed in degrees F per 100 ft or degrees C per 100 m.
Temperature at depth: T = T_surface + G * depth. Assumes a linear temperature profile (constant gradient).
Unit conversions: C = (F - 32) * 5/9. Gradient in C/100m = G(F/ft) * 5/9 * 30.48.
Assumptions: Linear geothermal gradient. No corrections for mud circulation cooling (Horner correction). BHT is assumed to be a static or corrected temperature.
Typical gradients: Normal range is 1.0 - 2.0 F/100ft. High gradients (>2.5) suggest geothermally active areas. Low gradients (<0.8) may indicate deep, cool basins or salt proximity.
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Book a free strategy call →Understanding Formation Temperature
Formation temperature is a critical parameter in petroleum engineering, affecting everything from mud properties and cement design to PVT behavior and production forecasting. The geothermal gradient describes the rate of temperature increase with depth and is primarily controlled by the local heat flow, thermal conductivity of the formations, and proximity to thermal anomalies.
The simplest approach assumes a linear temperature profile from the surface to total depth. While this is a reasonable first approximation in many sedimentary basins, the actual gradient can vary with lithology (salt has very high thermal conductivity, lowering the local gradient), depth, and tectonic setting.
Bottom-hole temperature (BHT) measurements from wireline logs must be corrected for the cooling effect of mud circulation. The Horner correction method uses multiple temperature readings at different times after circulation stopped to extrapolate the true static formation temperature. This calculator assumes BHT is already corrected or represents static conditions.
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