One of the Productivity Diagnostics methods based on relation between pressure integral
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| body | --uriencoded--G(t) = \int_0%5et \left( p_%7Bwf%7D(\tau) - p_e(\tau) \right) d\tau |
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and
total sandface flowrate cumulatives | LaTeX Math Inline |
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| body | --uriencoded--Q_t(t) = \int_0%5et q_t(\tau) d\tau |
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where
| production/injection time |
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| body | --uriencoded--p_%7Bwf%7D |
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| bottomhole pressure as function of time |
It shows unit slope on log-log plot for stabilized reservoir flow:
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G(t) = J^{-1} Q_t(t) |
where
In case pressure data is available for a fair interpolation it is recommended to plot sandface cumulatives rather than surface which provides better linearity with pressure integral for Steady-State flow.
Although it is equally applicable to producers and injectors, due to lack of BHP and formation pressure data availability for producers in most practical cases in the past the Hall plot analysis was mostly applied for water injectors.
The pressure integral
is usually calculated over interpolated values of
formation pressure and
bottomhole pressure :
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G(t) = \int_0^t \left( p_{wf}(\tau) - p_e(\tau) \right) d\tau = \sum_k \left( p_{wf}(\tau_k) - p_e(\tau_k) \right) \delta \tau_k |
See Also
Petroleum Industry / Upstream / Production / Subsurface Production / Field Study & Modelling / Production Analysis / Productivity Diagnostics
