The basic equations developed by M. King Hubbert to describe the water and buoyancy forces driving hydrocarbons through an aquifer can be expanded and combined with J. A. F. Plateau's equations on capillary pressure phenomena to allow study of oil migration and entrapment patterns. The new equations are used to evaluate the sensitivity of entrapment processes to variations in temperature, fluid densities, and geologic parameters. Water drive is not important except when the tops of the petroleum transporting strata have very low dips. In all other cases, oil movement is governed by buoyancy drive. Increases in capillary pressure sufficient to cause petroleum entrapment seem important only when porosities drop below 5%.

The equations are also used in a computer analysis to combine the effects of all the variables and examine two hypothetical field cases. Specifically, the computer model examines the impact of changes in transport strata transmissivity upon oil entrapment. The resulting changes in potentiometric surface gradients in a structure of low dip can cause significant changes in both entrapment potential and location of the trap on the structure.