Motivation




Inputs & Outputs



InputsOutputs

Cumulative subsurface water influx from aquifer

initial formation pressure

Subsurface water flowrate from aquifer

aquifer Productivity Index





aquifer transmissibility

aquifer relaxation time
Detailing Inputs

aquifer volume

aquifer area

pay area


Assumptions



Pseudo Steady State Flow

Oil field performs as single well with  cross-sectional area in 

Aquifer pressure is constant

Aquifer Productivity Index is constant



Equations



\frac{d Q_{AQ}}{dt} + \frac{1}{\tau} Q_{AQ} = J \cdot ( p_i - p(t))



J_{AQ} = \frac{2 \pi \sigma}{\ln \frac{A_{AQ}}{A_e} - \frac{3}{4} }




q_{AQ}=\frac{d Q_{AQ}}{dt} 


where

water influx from aquifer at time moment

aquifer transmissibility

aquifer relaxation time

initial formation pressure

aquifer area

pay area




Const PI expansion:

q_{AQ} = \frac{d Q_{WAQ}}{dt} = J \cdot ( p_{AQ} - p(t))


Finite-volume reservoir PSS depletion:

p_{AQ} = p_i - \frac{Q_{WAQ}}{V_{WAQ} c_t}



See Also


Petroleum Industry / Upstream / Subsurface E&P Disciplines / Field Study & Modelling / Aquifer Drive / Aquifer Drive @model

Reference


 1.   Fetkovich, M.J. 1971. A Simplified Approach to Water Influx Calculations—Finite Aquifer Systems. J Pet Technol 23 (7): 814–28. SPE-2603-PAhttp://dx.doi.org/10.2118/2603-PA