Total open pore volume around the well where reservoir flow is initiated by production or injection from a given well or group of wells.

There are three major types of the drainage volumes:

Dynamic drainage volume of a wellwhich is formed dynamically depending on the nearby well production and injection
Potential drainage volume of a wellwhich can be formed in case a given well is working alone on the whole field (no interference with other wells)
Jointly drained volume of a group of wellswhich is formed dynamically by production and injection of all wells

For homogeneous reservoir it can be estimated as:

V_e = A_e \, h_e \, \phi_e


effective formation thickness

effective porosity

drainage area

See also

Physics /  Fluid Dynamics / Percolation

Petroleum Industry / Upstream / Subsurface E&P Disciplines / Field Study & Modelling / Drainage (fluid flow)

Drainage area (Ae) ] [ Drainage radius (re) ]