The paper discusses examples of wellhead and bottomhole pressure analysis during hydraulic fracturing. Horner and Nolte methods are used for pressure fall-off curves interpretation. These methods are implemented in the minifrac analysis module in RN-GRID, the corporate hydraulic fracturing simulator. The shortcomings of the Horner method are shown by practical examples, including reservoir pressure estimate accuracy dependence on pressure fall-off curve length. On the other hand, the Nolte approach enables to diagnose after-closure-analysis (ACA) flow regimes and enhance reservoir parameters estimate accuracy, if pseudo-linear and pseudo-radial flow regimes are distinguished. The paper compares reservoir pressure values obtained by fall-off interpretation via Horner and Nolte methods to average pressure estimates by drill stem formation tests.
The paper also discusses examples of how to enhance accuracy of decline curve analysis for pumping production wells using permanent downhole gauges (PDG) pressure data and results of fall-off curves after ACA interpretation. The decline curve analysis results obtained for the initial pressure as a first point registered by PDG and for initial pressure obtained by ACA are matched.
The ACA results can be used to forecast well production in new well drilling areas. The displacement fluid efficiency estimates are compared with well production for a field sector. The result obtained concludes that the ACA displacement fluid efficiency allows one to forecast production of newly drilled wells with sufficient accuracy.
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