'''Well Inflow Calculator'''
import math

def annulusCrossSectionalArea(id, od):
    '''Calculates cross-sectional area of an annulus'''
    return math.pi/4*(math.pow(od,2)-math.pow(id,2))

bblPerIn3 = 0.00010307

casingID = 5.0
tubingOD = 2.375

dailyProduction  = 13.36 #BBL
fluidLevelChange = -23.0 #ft
fluidLevelChangeInches = fluidLevelChange * 12.0
casingAnnulusArea = annulusCrossSectionalArea(tubingOD, casingID)

wellInflowBBL = fluidLevelChangeInches * casingAnnulusArea * bblPerIn3 + dailyProduction
print ("Inflow:",wellInflowBBL, "BBL")
wellInflowRate = wellInflowBBL / 24.0
print ("Inflow Rate:", wellInflowRate, "BBL/HR")