Determine the IPR for a well at the time when the average reservoir pressure will be 1,500 psig. The following data are obtained from laboratory tests of well fluid samples: Reservoir properties Average pressure (psig) Productivity index J* (stb/day-psi) 1.25 Present Future 2,200 1,500 Oil viscosity (cp) 3.55 3.85 Oil formation volume factor (rb/stb) 1.20 1.15 Relative permeability to oil 0.82 0.65