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In a solution (or dissolved) gas drive reservoir, the oil-bearing rock is completely surrounded by impermeable barriers. As the reservoir pressure drops during production, expansion of the oil and its dissolved gas provides most of the reservoir's drive energy ([[:File:Drive-mechanisms-and-recovery_fig3.png|Figure 3]]). Additional energy is obtained from the expansion of the rock and its associated water.

In a solution (or dissolved) gas drive reservoir, the oil-bearing rock is completely surrounded by impermeable barriers. As the reservoir pressure drops during production, expansion of the oil and its dissolved gas provides most of the reservoir's drive energy ([[:File:Drive-mechanisms-and-recovery_fig3.png|Figure 3]]). Additional energy is obtained from the expansion of the rock and its associated water.

Depending on its discovery pressure, a solution gas drive reservoir can be initially either [[undersaturated]] or [[saturated]].<ref name = pt10r25>Odeh, A. S., 1986, Reservoir fluid flow and natural drive mechanisms, in IHRDC Video Library for Exploration and Production Specialists, Manual for Module PE502: Boston, MA, IHRDC, p. 69–120.</ref> In an undersaturated reservoir, the reservoir pressure is greater than the bubblepoint of the oil. No free gas exists in the reservoir while the pressure remains above the bubblepoint. The reservoir drive energy is provided only by the limited expansion of the oil, rock, and water. In a saturated reservoir, the reservoir pressure is at the bubblepoint. As soon as oil is produced, the pressure drops and bubbles of solution gas form in the reservoir. This solution gas liberation causes the oil to shrink, but the oil shrinkage is more than offset by solution gas expansion, the primary source of reservoir drive energy below the bubblepoint.

Depending on its discovery pressure, a solution gas drive reservoir can be initially either [[undersaturated]] or [[saturated]].<ref name = pt10r25>Odeh, A. S., 1986, Reservoir fluid flow and natural drive mechanisms, in IHRDC Video Library for Exploration and Production Specialists, Manual for Module PE502: Boston, MA, IHRDC, p. 69–120.</ref> In an undersaturated reservoir, the reservoir pressure is greater than the bubblepoint of the oil. No free gas exists in the reservoir while the pressure remains above the bubblepoint. The reservoir drive energy is provided only by the limited expansion of the oil, rock, and water. In a saturated reservoir, the reservoir pressure is at the bubblepoint. As soon as oil is produced, the pressure drops and bubbles of solution gas form in the reservoir. This solution gas liberation causes the oil to shrink, but the oil shrinkage is more than offset by solution gas expansion, the primary source of reservoir drive energy below the bubblepoint.