Calculate the production rate of a well in an oil reservoir at time of 20 days. The following data are given:

Flowing bottomhole pressure, p_wf =4000 psi

Porosity,f= 0.2

Oil saturation S_oi = 100%

Effective permeability, k = 20 md

Pay zone thickness, h = 100 ft

Initial reservoir pressure, p_i = 7000 psia

Bubble point pressure, p_b= 300 psia

Oil formation volume factor, B_o = 1.2 rb/STB

Oil viscosity,m= 2 cp

Total compressibility, c_t= 0.000015 psi^-1

Drainage area, A = 640 acres (reservoir radius, r_e = 2980 ft)

Wellbore radius, r_w= 0.328 ft

Skin factor, s = 0