An oil reservoir discretize to four centered grid-block with Ax1=750 ft, Ax2=1250 ft Ax3=750 ft, Ax4= 1000 ft, Ay= 600 ft, Az= 55 ft, Kx1= 50.5 md, Kx2= 70 md Kx3= 50 md, Kx4= 30 md, PHI= 0.26, Ct= 0.0000012 psi, = 9 cp, B= 1 RB/STB, time step= 30 days. The first grid-block is producing 120 STB/day and the third grid-block involve well with 225 STB/day injection rate. Determine pressure distribution in reservoir explicitly for two months if Pi=7100 psi. Assume no flow boundary, in the second month a new well start producing from the forth grid with same producing rate