Estimated Ultimate Recovery

Natural Depletion

(1)	$\begin{array}{l}\displaystyle EUR = \frac{Q_o}{V_o} = \frac{ (p_i - p_{wf \, min}) \, c_t}{(1-s_{wi})\, B_o} = \frac{ (p_i - p_{wf \, min}) }{(1-s_{wi})\, B_o} \, \big( c_r + s_{wi} c_w + (1-s_{wi})c_o \big)\end{array}$

EUR Deduction

(2)	$\begin{array}{l}\displaystyle c_t = \frac{1}{V_{\phi}} \frac{\partial V_{phi}}{\partial p}\end{array}$

For low compressible oil compressibility can be assumed constant $\begin{array}{l}c_t = \rm const\end{array}$ and the volume reduction can be related to pressure decline as:

(3)	$\begin{array}{l}\displaystyle \frac{\delta V_\phi}{V_\phi} = c_t \, \delta p = c_t \, (p_i - p_{wf \, min})\end{array}$

(4)	$\begin{array}{l}\displaystyle \delta V_\phi = Q_o \, B_o\end{array}$

and

(5)	$\begin{array}{l}\displaystyle V_o = s_o \, V_\phi = (1-s_{wi}) \, V_\phi\end{array}$

hence

(6)	$\begin{array}{l}\displaystyle \frac{Q_o \, B_o \, (1-s_{wi})}{V_o} = c_t \, (p_i - p_{wf \, min})\end{array}$

and

(7)	$\begin{array}{l}\displaystyle EUR = \frac{Q_o}{V_o} = \frac{ (p_i - p_{wf \, min}) \, c_t}{(1-s_{wi})\, B_o}\end{array}$

Water flooding

Gas flooding

WAG flooding

Chemical EOR

CО2 injection

Reference

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Page tree

Field Development Methods

Natural Depletion

Water flooding

CО2 injection

Reference