Gas Drive Research Paper

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Primary Drive Mechanisms
Primary drive mechanisms basically recover hydrocarbons from the reservoir using natural energy of the reservoir, not needing external energy whatsoever. Primary drive mechanisms will directly or indirectly declines the pressure of the reservoir or in other words, causing pressure depletion.
Solution Gas Drive
Solution gas drive is classified as oil reservoirs which initially does not contain free gas but instead develop free gas on pressure depletion and this drive requires the reservoir rock to be completely surrounded by impermeable barriers. This drive takes action when pressure falls below the bubble point and the expansion and exsolution of dissolved gases becomes the main source of energy. Other forms of energy may come from the expansion of the rock and water. This type of reservoir is said to be under saturated or saturated by which if it is under saturated, the pressure of the reservoir is bigger than the pressure at the bubble point and is vice versa for the saturated condition. If it is an under saturated reservoir, there will be no free gas existing until the reservoir pressure falls below the bubble point pressure and the energy drive is by the bulk expansion of the reservoir rock and liquids. For saturated reservoir, oil production comes from the expansion of bubbles of gas which is caused by the depletion of pressure. The oil and water will shrink slightly but the volume of exsolved gas and its subsequent expansion makes up for this.
From this drive, information such as pressure, GOR and fluid production history can be known. The pressure can drop greatly if the reservoir is initially under saturated due to the fact that compressibilities of rock water and oil is lower compared to gas. F...

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Compaction Drive
A reservoir is considered as a compaction drive is when the pore volume contraction takes prominently to overall expansion while the reservoir is saturated. This drive is supplemented by solution gas drive and may or may not by water/gas cap drive. This reservoir acts like their non-compaction counterparts except that they exhibit enhanced recoveries. For example, the oil recovery will be greater for a solution gas drive by which the compaction drive will act like a normal solution gas drive reservoir. This is because of the direct consequence of the extra rock expansion that compaction drive reservoirs actually have. Due to the extra compaction, some production occurs. For instance, the permeability may decline, fracture may happen and subsidence but all there problems are manageable and the result of compaction is very favorable.

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