Estimated Ultimate Recovery
EUR = \frac{Q_o}{V_o} = \frac{ (p_i - p_{wf \, min}) \, c_t}{(1-s_{wi})\, B_o} = \frac{ (p_i - p_{wf \, min}) }{(1-s_{wi})\, B_o} \, \big( c_r + s_{wi} c_w + (1-s_{wi})c_o \big) |
The definition of total compressibility
and can be split into rock, water, oil components:
For low compressible oil compressibility can be assumed constant and the volume reduction can be related to pressure decline as:
and
hence
and
|
EUR = E_S \, E_D = E_{SV} \, E_{SH} \, E_D |
Total sweep | Areal sweep | Vertical sweep | |||
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– sweep volume – pore volume | – sweep area – pore area | – sweep thickness – pore thickness |
E_D = \frac{1-s_{wi}-s_{or}}{1-s){wi}} |
Water and gas flodding.
Motivation = increas displacement as residual oil saturation to gas sweep is less than to water sweep .
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