c) Mention the factors affecting the displacement efficiency of any enhanced oil recovery process 20mks Question 3 a) With a well labelled diagram, describe how formation volume factor, viscosity, solution gas oil ratio and producing GOR vary with declining pressure. b) Mention the basic assumptions in a material balance equation. c) Mention 3 EOR processes and why they are used 20 marks Question 4 a) Define the Darcy fluid flow equation, why is it significant? b) Derive the expression for the average permeability of the reservoirs for a 3 layer reservoir with linear flow assuming there is no crossflow between the layers. 45 c) What factor/s affect the solubility of gas in crude oil. 20 marks Question 5 Experiments were made on a bottom-hole sample of the reservoir liquid taken from the University of Abuja Oil Field to determine the solution as and the formation volume actor as functions of Pressure. The following data, converted to practical units, were obtained from the measurements a) What type of reservoir was this insitu? Explain. b) What is the bubble point pressure? Explain the reason for your choice. c) Does the reservoir have an initial gas cap? Explain. 20marks