1. (30 points) 1) What can be injected into reservoirs for tertiary oil recovery processes? List at least three and briefly state their recovery mechanisms. 2) Under what conditions, the path line is the same as the stream line? 3) What are the assumptions made for Darcy's law? (List at least five for full credit) 1. (70 points) Consider a water injection well located at (0, 0) and a water production well at (D, 0) in an infinite 2-dimensional aquifer shown in the figure below. The permeability is k in both the x-direction and the y-direction. The pump rate is q for both the wells. The water viscosity is u and the aquifer thickness is h. The well bore radius is neglected. Porosity is o. At time of 0, a tracer was injected with water. The general equation for isotropic reservoir is given as follows: = 4kh i=1 q; m[(x-x;) + (y - yi) ] }+ qi 1 D=9.869233 x 10-13 m +C y D Tq 1) (10 points) What can be used as a tracer? X -q 2) (25 points) Derive expressions for velocity in x direction ux, and velocity in y direction uy. 3) (25 points) When will the tracer show up at the production well? (calculate the breakthrough time, T, for the tracer injection) 4) (10 points) If k = 300 md, u = 1 cp, q = 1000 ft/day, h = 10 ft, 6 = 0.2, D = 1000 ft, what is the breakthrough time, T in days?