Analysis of a flow test with smoothly varying rates
Input(s)
\(t_{1}\): Time at \(P_{w f 1}\) from Given Values or Trendline (h)
\(t_{2}\): Time at \(P_{w f 2}\) from Given Values or Trendline (h)
\(\mathrm{q}_{1}\): Flow Rate at \(\mathrm{P}_{\mathrm{wf} 1}(\mathrm{STB} /\) day \()\)
\(\mathrm{q}_{2}\): Flow Rate at \(\mathrm{P}_{\mathrm{wf} 2}(\mathrm{STB} /\) day \()\)
\(\mathrm{p}_{\mathrm{i}}\): Initial Pressure (psi)
\(\mathrm{p}_{\mathrm{wf} 2}\): Wellflow Pressure at Point 2 from Given Values or Trendline (psi)
\(\mathrm{p}_{\mathrm{wf} 1}\): Wellflow Pressure at Point 1 from Given Values or Trendline (psi)
\(\mathrm{p}_{\mathrm{wf}}\): Pressure Value at \(t=1 \mathrm{~h}(\mathrm{psi})\)
q: Flow Rate (STB/day)
B: Volume Factor (RB/STB)
\(\mathrm{h}\): Thickness of Reservoir (ft)
\(\mu\): Viscosity of Oil (cP)
\(\varnothing\): Porosity (fraction)
\(c_{t}\): Compressibility (1/psi)
\(\mathrm{r}_{\mathrm{w}}\): Wellbore Radius (ft)
Output(s)
\(\mathrm{m}\): Slope of Line (dimensionless)
\(\mathrm{k}\): Permeability \((\mathrm{mD})\)
s: Skin Factor (dimensionless)
Formula(s)
Reference(s)
Lee, J., Rollins, J. B., & Spivey, J. P. (2003). Pressure Transient Testing (Vol. 9). Richardson, Texas: Society of Petroleum Engineers, Page: 31.