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VFF DEEP INJECTION WELL NO. 1 <br /> PRESSURE FALLOFF ANALYSIS <br /> The pressure falloff , which was recorded after injection on <br /> March 31 , was used to determine the permeability of the injection <br /> interval using a program called ANALYZE . This program calculates <br /> the expected pressure behavior in a well given the flow history . <br /> It then iterates on the permeability thickness to optimize the <br /> fit between measured and calculated pressure response. ANALYZE <br /> can combine the effect of several rate changes and is , therefore , <br /> especially good for analyzing; variable rate well tests . The <br /> printout from ANALYZE is attached . <br /> A Horner plot of the pressure falloff was used to determine <br /> the initial reservoir pressure (see Figure ) . The final <br /> straight line portion of the Horner plot intersects the Log <br /> (t + dt) /dt = 0 line at 1216 . 3 psia . the slope of the line is <br /> 0 . 34 psi/cycle which indicates that the transmissivity (kh/u) is <br /> about 1 . 6E6 and ft/cp. <br /> The production and injection history along with the reser- <br /> voir pressure from the Horner plot were entered into ANALYZE . <br /> The following values were used to calculate the OCh input of <br /> 5 . 6E-4 ft/psi : <br /> porosity 0 . 30 <br /> net thickness ( h) = 2S0 ft <br /> ( from mud log) <br /> compressibility (C) = 7 . 5E-6 1/psi <br /> assumed value , typical for sandstone aquifer) <br /> viscosity (u ) = 0 . 75 cp <br /> (Wate=r at `0 F ) <br /> ANALYZE calculated a kh/u of 1 . S7E5 and ft/cp which , with the <br /> above assumptions , indicates that the permeability(k) is 4710 md . <br /> These results are consistent with the Horner plot analysis . <br />