Vik #1 well produces light gravity oil from a cretaceous chalk formation. The test before stimulation gave a skin of +18.5, and after the stimulation the skin was -4.2. Other parameters: rw = 0.29ft, Ho = 0.31 cp, k = 24 mD, h = 80 ft, B, = 1.5 Before/after the stimulation, calculate: (1) Flow efficiency, (2) Apparent wellbore radius, (3) Pressure loss as a function of flow rate due to skin factors.