(50 points) A reservoir is surrounded by an aquifer. Although fluid and rock properties are not provided, the water influx constant, U, is estimated to be 1000bbl/psi, the initial encroachable water in the aquifer and productivity index have been determined as Wei= 6.0107RB and J=22RB/psi-day, respectively. The effective reservoir radius has been estimated as 10,000ft and the effective radius of the aquifer estimated as 30,000ft. The initial pressure is 3000 psia. Finally, the dimensionless time, to can be computed as: tD=ctrs20.0002637kt=2.0103t Where t is given in hours. a. (10 points) If the reservoir pressure suddenly dropped to a constant value of 2000 psia, determine the minimum time (how many hours) would need to pass before a small pot aquifer could be used to predict the cumulative water influx? Defend your answer with a calculation and/or explanation. A range of answers will be accepted. b. (20 points). Now assume that the average reservoir pressure as a function of time in an oil reservoir surrounded by an aquifer is given in the table below. Note that the time is given in days. Compute the cumulative water influx (bbls), We, at 300 days using the van Everdingen and Hurst (VEH) method. Show all work and calculations. c. (15 points) Compute the cumulative water influx (bbls), We, at 300 days using the Fetkovich method. Show all work and calculations d. (5 points) Compute the cumulative water influx (bbls), We, at 200 days using the Fetkovich method