Pressure transient survey in producer during the pressure rise period caused by shutting well down or reducing its production rate (see Fig. 1):
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Fig 1. Build-up Survey starting after well is closed at 3,600 hrs and going through pressure recovering for 7 days (blue dots). The grey dash line shows bottom hole pressure history before 3,600 hrs in case it would have been recorded. |
Interpretation
Interpretation of BUS is based on:
- visual analysis of PTA diagnostic plot
- selecting pressure diffusion model from PTA Type Library
- fitting selected parameters of pressure diffusion model to pressure gauge data records
In some cases one can uses Horner model with simplified version of BUS interpretation procedure.