Assignment #4

University of Alberta School of Mining and Petroleum Engineering Assignment 4, PET E 295: Fundamental Reservoir Engineering, Fall 2023 Submission deadline: Monday, Nov. 20 at 4:00 p.m. Exercise 1: An oil wellbore is produced at a constant bottomhole flowing pressure of 2750 psi. The reservoir rock and fluids have the following properties: μ o =0.9 cp k o =40 md r w =0.3 ft c t = 15×10 -6 psi -1 B o =1.2 res bbl/STB f = 0.2 p i =3000 psi h=25 ft a) Calculate the cumulative production after operating this wellbore for 1 hour. b) Calculate the flow rate after operating the wellbore for 2 hours Assume infinite acting conditions during this period. Exercise 2: A wellbore with the parameters below starts producing from a reservoir at a constant rate of 1,000 STB/day. s=0 p i =2,500 psi r w =4 in. k o =600 md h=32 ft Φ=0.15 µ o =2 cp c t =12×10 -6 psi -1 B o =1.333 res bbl/STB r e =1,000 ft The reservoir is volumetric with zero water influx (no aquifer connection to the reservoir). a) Determine when the well becomes finite-acting b) Plot the pressure profile in the reservoir after half an hour of production c) Use the dimensionless formulae and determine the wellbore pressure variation with time. Use the following times in your pressure calculations: t=0, 0.01, 0.1, 1, 2, 7, 24 hours, 2, 5, 10, 30, 40 days. d) Plot the pressure profile in the reservoir after 30 days of production. e) Plot the pressure profile after 30 days of production, assuming the reservoir was connected to an unlimited-size aquifer. f) Compare the results of Part (d) and Part (e) and comment. Exercise 3: Reservoir and well data are: P e =3,350 psi p wf =3,050 psi c t = 10 -5 psi -1 Q o =900 STB/day μ =0.65 cp r e =2,000 ft r w =0.5 ft B o =1.150 res bbl/STB