Radius of Investigation
Radius of investigation in drilling and reservoir engineering is the maximum radial distance from the wellbore at which the effects of fluid flow or pressure disturbance can be observed during a given period. This concept is crucial for understanding the area of the reservoir that contributes to production and is affected by the well's activities.
Key Points about Radius of Investigation
Reservoir Properties - Permeability: Higher permeability increases the ROI. Porosity: Influences the storage capacity and rate of pressure propagation. Compressibility: Higher compressibility slows pressure propagation, reducing the ROI.
Fluid Properties - Viscosity: Higher viscosity results in slower pressure propagation, decreasing the ROI.
Time - The ROI increases with time as the pressure disturbance propagates further into the reservoir.
Flow Regime - The type of flow (radial, linear, or spherical) affects the pressure propagation pattern.
Radius of Investigation Formula |
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| \( r_i \;=\; 0.0359 \cdot \left( \dfrac{ k \cdot t }{ n \cdot \eta \cdot \beta } \right)^{0.5} \) | ||
| Symbol | English | Metric |
| \( r_i \) = Radius of Investigation at the End of Injection Time |
- | \(m\) |
| \( k \) (Greek symbol rho) = Permability | - | \(mD\) |
| \( t \) = Time | - | \(h\) |
| \( n \) = Porosity | - | \(dimensionless\) |
| \( \eta \) (Greek symbol eta) = Viscosity | - | \(cP\) |
| \( \beta \) (Greek symbol beta) = Total Compressibility (1/psi) | - | \(Pa\) |
