Pressure transient survey in injector during the pressure rise period caused by opening well for injection or increasing its injection rate (see Fig. 1).
Despite the terminology conflict the Injection survey is widely called Drawdown (DD) similar to producing wells.
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Fig 1. Injection pressure decline (blue dots) for 2,300 hrs after opening the well for injection at 100 m3/d. |
Interpretation
Interpretation of DD is based on:
- visual analysis of PTA diagnostic plot (see Fig. 1)
- selecting pressure diffusion model from PTA Type Library
- fitting selected parameters of pressure diffusion model to pressure gauge data records (see Fig. 2)
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Fig. 1. PTA Diagnostic Plot for vertical well in single-layer homogeneous reservoir with impermeable circle boundary (PSS). Gauge pressure is in blue and log-derivative is in red. | Fig. 2. Pressure diffusion model fitting to pressure gauge data. Gauge pressure is in blue and log-derivative is in red. |
See Also
Petroleum Industry / Upstream / Subsurface E&P Disciplines / Well Testing / Pressure Testing
[ Pressure Transient Analysis (PTA) ][ Pressure Build-Up (PBU) = Build-Up Survey (BUS) ][ Drawdown survey (DD) ]