Ratio of field-wide Cumulative oil production Q^{\uparrow}_O to field-wide Cumulative water injection Q_{WI}^{\downarrow}:
| (1) | {\rm ΣPIR} = \frac{Q^{\uparrow}_O}{Q^{\downarrow}_{WI}} |
It measures how efficiently waterflood supports the oil production and represent one of the key Waterflood Diagnostics.
The PIR can be related to the current Instantaneous Voidage Replacement Ratio (IVRR) as:
| (2) | {\rm PIR}= \frac{1}{\rm IVRR} \cdot \frac{1-Y_w}{Y_w + (1-Y_w) \, \left[ \frac{B_o}{B_w} + \frac{B_g}{B_w} \, ( {\rm GOR} - R_s) \right] } = \frac{1}{\rm IVRR} \cdot \frac{1}{{\rm WOR} + \, \left[ \frac{B_o}{B_w} + \frac{B_g}{B_w} \, ( {\rm GOR} - R_s) \right] } |
(see (Instantaneous Voidage Replacement Ratio = IVRR:3) for derivation)
See Also
Petroleum Industry / Upstream / Production / Subsurface Production / Field Study & Modelling / Production Analysis / Waterflood Diagnostics