Note on calculation of PWRI well injectivity

The calculation can be made from only the most basic data: injection rate (Q), injection pressure Pwf (corrected for bottomhole flowing conditions), and far-field reservoir pressure Pe. In oilfield units, the injectivity index is commonly calculated as: (1) where Q is in STB/d and P in psia. Additional data required includes permeability kw in ... ................
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