Carbon dioxide flooding experiment. One of the most promising methods for extracting crude oil emplo
Question: Carbon dioxide flooding experiment. One of the most promising methods for extracting crude oil employs a carbon dioxide (CO2) flooding technique. CO2, when flooded into oil pockets, enhances oil recovery by displacing the crude oil. In a microscopic investigation of the CO2 flooding process, flow tubes were dipped into sample oil pockets containing a known amount of oil (Journal of Petroleum Technology, Aug. 1982). The oil pockets were flooded with CO2 and the percentage of oil displaced was recorded. The experiment was conducted at three different flow pressures and three different dipping angles. The displacement test data are recorded in the accompanying table.
CO2FLOOD
![]() per square inch |
Dipping Angle x2, degrees |
Oil Recovery y, percentage |
1,000 | 0 | 60.58 |
1,000 | 15 | 72.72 |
1,000 | 30 | 79.99 |
1,500 | 0 | 66.83 |
1,500 | 15 | 80.78 |
1,500 | 30 | 89.78 |
2,000 | 0 | 69.18 |
2,000 | 15 | 80.31 |
2,000 | 30 | 91.99 |
a. Write the complete second-order model relating percentage oil recovery y to pressure x1 and dipping angle x2.
b. Plot the sample data on a scattergram, with percentage oil recovery y on the vertical axis and pressure x1 on the horizontal axis. Connect the points corresponding to the same value of dipping angle x2. Based on the scattergram, do you believe a complete second-order model is appropriate?
c. Fit the interaction model to the data. Give the least-squares prediction equation.
d. Construct a plot similar to the scattergram of part b, but use the predicted values from the interaction model on the vertical axis. Compare the two plots. Do you believe the interaction model will provide an adequate fit?
e. Check model adequacy using a statistical test with a = .05.
Is there evidence of interaction between pressure x1 and dipping angle x2? Test using a = .05.
Deliverables: Word Document
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