Figure 1. Schematic illustration of water injection in an oil reservoir. Cross section show the distribution of oil and water before and after the water has displaced the oil in porous matrix.

From

Application of Homotopy Analysis Method in One-Dimensional Instability Phenomenon Arising in Inclined Porous Media

Kajal K. Patel, M. N. Mehta, Twinkle R. Singh

American Journal of Applied Mathematics and Statistics. 2014, 2(3), 106-114 doi:10.12691/ajams-2-3-4