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Reservoir EngineeringThermal Gradients

Thermal Diffusivity Formula

α=kρCp\alpha=\frac{k}{\rho C_p}

Thermal Diffusivity calculates thermal diffusivity for thermal gradients workflows in reservoir engineering.

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How engineers use this formula

Use this formula when the listed inputs (k_thermal, rho, C_p) are known and the assumptions behind the cited thermal gradients relationship match the engineering case being checked.

Assumptions

  • Input values are representative for the well, reservoir, fluid, or equipment case being evaluated.
  • The declared units match the field-unit constants used in the formula.
  • The cited formula applies to the selected petroleum engineering workflow.

Limitations

  • The calculation does not replace a full engineering model or operating procedure.
  • Accuracy depends on the source correlation, assumptions, input quality, and unit consistency.

Common mistakes

  • Mixing unit systems without converting the inputs.
  • Using default example values as field recommendations.
  • Applying the formula outside the source assumptions.

Default example

Using the default inputs, alpha equals 0.000001 m2/s.

k_thermalW/(m*K)

1.5

rhokg/m3

2200

C_pJ/(kg*K)

1000

Inputs

k_thermal

W/(m*K)

Thermal Conductivity

rho

kg/m3

Density

C_p

J/(kg*K)

Specific Heat Capacity at Constant Pressure

Outputs

alpha

m2/s

Thermal Diffusivity

k_thermal

W/(m*K)

Thermal Conductivity

rho

kg/m3

Density

C_p

J/(kg*K)

Specific Heat Capacity at Constant Pressure

Source and review

reviewed

Transport Phenomena, Bird, R.B., Stewart, W.E., Lightfoot, E.N. (2002)

Bird, R.B., Stewart, W.E. and Lightfoot, E.N. 2002. Transport Phenomena, 2nd ed., Chapter 9, Page 268.

Source

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