Page 203 - Formulas and Calculations for Petroleum Engineering
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196 Formulas and calculations for petroleum engineering



              3.45   Pressure buildup equation (Horner equation)

              Input(s)
                 P i :  Initial Reservoir Pressure (psi)
                 Q o :  Stabilized Well Flow Rate before Shut-in (bbl/d)
                 m o :  Oil Viscosity (cP)
                 B o :  Oil Formation Volume Factor (rb/stb)
                 k:  Permeability (mD)
                 h:  Height (ft)
                 t p :  Flowing Time before Shut-in (day)
                 Dt:  Shut-in Time (day)

              Output(s)

                 P ws :  Pressure (psi)

              Formula(s)

                                                                            t + Dt

                                                            o
                                                                o
                                                     162:6   Q   B   m o    p
                                           P ¼ P                        log
                                                 i
                                            ws
                                                           k   h             Dt
              Reference: Ahmed, T., McKinney, P.D. 2005. Advanced Reservoir Engineering, Gulf Publishing of Elsevier, Chapter: 1,
              Page: 54.
              3.46   Radius of investigation
              Input(s)

                 k:  Permeability (mD)
                 t:  Time (h)
                 ø:  Porosity (fraction)
                 m:  Viscosity (cP)
                 c t :  Total Compressibility (1/psi)

              Output(s)
                 r i :  Radius of Investigation at the end of Injection Time (ft)


              Formula(s)

                                                                         !
                                                                        0:5
                                                                 k   t
                                                  r ¼ 0:0359
                                                   i
                                                               ø   m   c
                                                                      t
              Reference: Ahmed, T., McKinney, P.D. 2005. Advanced Reservoir Engineering, Gulf Publishing of Elsevier, Chapter: 1,
              Page: 134.

              3.47   Radius of investigation (flow time)

              Input(s)
                 t:  Flow time (h)
                 k:  Permeability (mD)
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