What is a solution gas drive?

Solution gas drive is a mechanism by which dissolved gas in a reservoir will expand and become an energy support to produce reservoir fluid. Because compressibility of oil and rock is very low, only a small amount of fluid can be produced and typically the volume is around 1-2% of oil in place.

What is internal gas drive?

[in′tərn·əl ′gas ‚drīv] (petroleum engineering) A primary oil recovery process in which oil is displaced from the reservoir by the expansion of the gas originally dissolved in the liquid. Also known as dissolved-gas drive; gas depletion drive; solution gas drive.

What is water drive?

When reservoir pressure drops due to production, the compressed water in an aquifer expands into a reservoir and it helps pressure maintenance. This mechanism is called “water drive”. Water from an aquifer below a reservoir pushes oil towards producing wells and eventually producing wells will have higher water.

What is depletion drive?

A depletion drive reservoir is characterized by a rapidly increasing gas–oil ratio from all wells, regardless of their structural position. After the reservoir pressure has been reduced below the bubble point pressure, gas evolves from solution throughout the reservoir.

What is gravity drainage?

Gravity drainage is a recovery process in which gravity acts as the main driving force and where gas replaces the voidage volume. In other words, it is a gas/oil displacement in which gravity forces are dominating.

What is free gas?

Gas that exists in the reservoir in the gaseous phase rather than in solution. As soon as formation pressure drops below the bubblepoint, gas is evolved. This is referred to as free gas while it is in the reservoir.

What is reservoir-drive?

Natural forces in the reservoir that displace hydrocarbons out of the reservoir into the wellbore and up to surface. Reservoir-drive mechanisms include gasdrive (gas cap or solution gasdrive), waterdrive (bottomwater drive or edgewater drive), combination drive, and gravity drainage.

What is combination drive?

A combination or mixed drive occurs when two or more of the primary drive mechanisms are present in the same reservoir. A combination drive may also occur when one or more of the primary drive mechanisms are assisted by gravity drainage.

What is water drive in oil and gas?

1. n. [Well Completions] A reservoir-drive mechanism whereby the oil is driven through the reservoir by an active aquifer. As the reservoir depletes, the water moving in from the aquifer below displaces the oil until the aquifer energy is expended or the well eventually produces too much water to be viable.

What is drainage in oil and gas?

1. n. [Formation Evaluation, Enhanced Oil Recovery] The process of forcing a nonwetting phase into a porous rock. Oil migrates into most reservoirs as the non-wetting phase, so initial charging of the reservoir is a drainage process.

What is gravity drainage in oil and gas?

What is gas cap?

1. n. [Well Completions] The gas that accumulates in the upper portions of a reservoir where the pressure, temperature and fluid characteristics are conducive to free gas. The energy provided by the expansion of the gas cap provides the primary drive mechanism for oil recovery in such circumstances.

What is solutionsolution gas drive?

Solution gas drive is the mechanism whereby the lowering of reservoir pressure through production in an undersaturated reservoir causes the oil to reach the bubble point where gas starts to evolve from solution.

How is additional energy obtained from a solution gas drive reservoir?

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. In an undersaturated reservoir, the reservoir pressure is greater than the bubblepoint of the oil.

What is the source of energy in a gas cap drive reservoir?

In a gas cap drive reservoir, the primary source of reservoir energy is an initial gas cap, which expands as the reservoir pressure drops ( Figure 4 ). Additional energy is provided by the expansion of solution gas released from the oil.

What is the difference between saturated and undersaturated gas drive reservoir?

Depending on its discovery pressure, a solution gas drive reservoir can be initially either undersaturated or saturated. 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.