Depending on context may mean:
The major difference between cumulative offtakes and cumulative production is that cumulative offtakes accounts for the shrinkage factors and cross-phase exchange coefficients which depend on formation pressure p_e(t) and formation temperature T(\tau) and may vary over time:
| Cumulative offtakes | Cumulative production |
|---|---|
Q = \int_0^t B(p(\tau), T(\tau)) q(\tau) d\tau | Q = \int_0^t q(\tau) d\tau |