Productivity Index for a Gas Well Formula |
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| \( J \;=\; \dfrac{ \mu \cdot h }{ 1422 \cdot T \cdot \left( 0.5 \cdot ln \cdot \left( \dfrac{ 4 \cdot A }{ 1.781 \cdot k \cdot WB_r^2 } \right) + S \right) }\) | ||
| Symbol | English | Metric |
| \( J \) = Productivity Index for a Gas Well | \(MSCF/day/psi^2/cP\) | - |
| \( \mu \) (Greek symbol mu) = Permability | \(mD\) | - |
| \( h \) = Thickness | \(ft\) | - |
| \( T \) = Temperature | \(R\) | - |
| \( ln \) = Natural Logarithm | \(dimensionless\) | - |
| \( A \) = Drainage Area | \(ft^2\) | - |
| \( k \) = Shape Factor | \(dimensionless\) | - |
| \( WB_r \) = Wellbore Radius | \(ft\) | - |
| \( S \) = Skin | \(dimensionless\) | - |
Productivity index for a gas well, abbreviated as \(J\), also called Gas Productivity Index, Productivity Index, is a measure of the well's ability to produce gas as a function of the pressure drop between the reservoir and the wellbore. It quantifies the relationship between the gas flow rate and the drawdown pressure, providing insight into the well's performance and efficiency.
Key Points about Productivity Index
Gas Flow Rate - This is the rate at which gas is being produced from the well.
Reservoir Pressure - This is the pressure within the reservoir.
Flowing Bottom-Hole Pressure - This is the pressure at the bottom of the well when gas is flowing.
Productivity Index Usage
Evaluating Well Performance - A higher \(J\) indicates a more productive well for a given pressure drawdown.
Well Comparison - \(J\) allows for the comparison of different wells within the same reservoir or across different reservoirs.
Reservoir Management - Helps in planning the development and production strategies for a gas field.
