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Production EngineeringWell Performance

Safety Relief Valve Vapor Flow Capacity Formula

w=BCKoAP(MZT)0.5w=BCK_oAP\left(\frac{M}{ZT}\right)^{0.5}

Safety Relief Valve Vapor Flow Capacity calculates valve vapor weight flow capacity for well performance workflows in production engineering.

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How engineers use this formula

Use this formula when the listed inputs (B_v, C_v, K_o, A_orifice, P_rel, M_gas, Z, T_in) are known and the assumptions behind the cited well performance 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, w_relief equals 31,447.114462 lb/h.

B_vdimensionless

356

C_vdimensionless

0.9

K_odimensionless

0.85

A_orificein2

0.5

P_relpsi

1200

M_gasdimensionless

18

Zdimensionless

0.9

T_inR

540

Inputs

B_v

dimensionless

Conversion Constant

C_v

dimensionless

Specific-Heat-Ratio Flow Coefficient

K_o

dimensionless

Valve Discharge Coefficient

A_orifice

in2

Effective Discharge Area

P_rel

psi

Upstream Relieving Pressure

M_gas

dimensionless

Gas Molecular Weight

Z

dimensionless

Gas Compressibility Factor

T_in

R

Inlet Temperature

Outputs

w_relief

lb/h

Valve Vapor Weight Flow Capacity

A_orifice

in2

Effective Discharge Area

P_rel

psi

Upstream Relieving Pressure

Source and review

reviewed

Gas Conditioning and Processing, Campbell, J. M. (1992)

John M. Campbell. 1992. Gas Conditioning and Processing, Campbell Petroleum Series, Vol. 1, Page 296.

Source

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