# Outlet Pressure in Gas Transportation Pipelines

Designing a long-distance pipeline for transportation of natural gas requires knowledge of flow formulas for calculating capacity and pressure requirements. The friction loss component applies to any type of flow at any pipe angle and causes a pressure drop in the direction of flow.

In gas transportation pipelines, the gas compressibility factor depends on pressure and the friction factor depends on flow rate which affects the pressure drop through the pipeline. Several correlations are developed to estimate gas flow capacity through pipelines considering these effects. In addition, the outlet pressure can be estimated using measured inlet pressure and gas rate.

Reference: Petroleum Production Engineering, Boyun Guo, Xinghui Liu, Xuehao Tan

### Correlations

- Weymouth (Horizontal and Inclined Pipeline)
- Panhandle-B (Horizontal Pipeline)

### Input Parameters

Name | Input Value - Unit | Converted Value | Validity | Link to Calculation Page | |||
---|---|---|---|---|---|---|---|

Inlet Pressure | 600 | psi | |||||

Gas Rate | 0.21247 | Million ft/day - mmscf/day | |||||

Pipe Length | 200 | Mile | |||||

Pipe Inside Diameter | 2.06 | in | |||||

Pipe Inclination (Degrees from Horizontal) | 0 | Degrees | Positive value when pipe outlet elevation is bigger than pipe inlet | ||||

Gas Specific Gravity (ɣ_{g}) | 0.8 | SG | Average Surface Gas Gravity (ɣ_{g}) | ||||

Pipeline Average Temperature | 539.67 | °R | |||||

Relative Roughness (ε/d) More Details | 0.00005 | - | |||||

Friction Factor Calculation Method | 1 | ||||||

N2 Content | 0 | % | |||||

CO2 Content | 0 | % | |||||

H2S Content | 0 | % | |||||

Z-Factor Calculation Method | 3 | ||||||

Pseudo Properties Calculation Method | 2 | ||||||

Pseudo Critical Properties Correction Method | 2 | ||||||

CALCULATE | |||||||

## Results | |||||||

Correlation | Calculated Value | Warnings | Remarks | ||||

Weymouth (Horizontal and Inclined Pipeline) | |||||||

Outlet Pressure | 199.97 | psi | The value of -999.25 is returned when gas rate is not valid for the given pipe specifications Calculations are done depending on the pipeline inclination | ||||

Panhandle-B (Horizontal Pipeline) | |||||||

Outlet Pressure | 497.28 | psi | The value of -999.25 is returned when gas rate is not valid for the given pipe specifications Calculations are done considering zero inclination (Horizontal Pipeline) |