What is the reservoir-drive mechanism?
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 a water drive reservoir?
Waterdrive (or water drive) petroleum reservoirs are characteristically bounded by and in communication with aquifers. As pressure decreases during pressure depletion, the compressed waters within the aquifers expand and overflow into the petroleum reservoir.
What are the types of drive mechanism?
There are five common drive mechanisms:
- Water drive.
- Gas expansion.
- Solution gas.
- Rock or compaction drive.
- Gravity drainage.
What is combination drive reservoir?
The mechanism of displacement by fluids can be reproduced artificially by strategically injecting water or gas in wells, and this method can be combined with natural mechanisms as gravitational segregation and/or capillary expulsion, increasing recovery.
What are the three types of primary recovery for an oil reservoir?
There are three main types of enhanced oil recovery:
- Thermal Recovery. This is the most prevalent type of EOR in the USA and works by heating the oil to reduce its viscosity and allowing easier flow to the surface.
- Gas Injection.
- Chemical Injection.
Which is the most efficient recovery mechanism for a gas reservoir?
Waterdrive is the most efficient drive mechanism, followed by gasdrive and gravity drainage. Reservoir-drive mechanisms are also called natural drives.
What are the sources of reservoir pressure?
Reservoir pressure: measurement – gradients – sources – variations. Temperature: measurement – geothermal gradient – uses of thermal measurements – sources of heat energy – effects of heat.
What is a drive mechanism?
The natural energy of a reservoir can be used to move oil and gas toward the wellbore. Used in such a fashion, these sources of energy are called drive mechanisms. Drive mechanisms are determined by the analysis of historical production data, primarily reservoir pressure data and fluid production ratios.
What is the primary drive mechanism?
The natural energy of a reservoir can be used to move oil and gas toward the wellbore. Used in such a fashion, these sources of energy are called drive mechanisms. The three primary oil reservoir drive mechanisms are solution gas drive, gas cap drive, and water drive.
What is the difference between EOR and IOR?
In world oil-and-gas practice, two different terms are in use: EOR (enhanced oil recovery) meaning intensive, forcible methods; and IOR (improved oil recovery) – advanced and moderate methods.
Which is the least efficient drive mechanism?
Water drive and gas cap expansion are both displacement type drive mechanisms and have relatively high recoveries. Solution gas drive is a depletion type drive and is relatively inefficient.
How is reservoir pressure calculated?
The reservoir pressure can be determined by measurement using bottomhole pressure gauge, well testing, or graphics. Generally, formation pressure is assessed by the pressure gradient and the pressure coefficient.
How does the drive mechanism in a gas reservoir work?
As with oil reservoirs, this drive mechanism occurs when the reservoir is in communication with a water-bearing aquifer. As the reservoir pressure declines, the rock and water in the aquifer expand, and water is expelled from the aquifer and into the reservoir. This encroachment of water into the reservoir provides pressure support.
How does water drive recovery work in a reservoir?
Water drive recovery increases with the strength of the aquifer if water production can be minimized. As with gas cap drive reservoirs, this is done most easily in reservoir geometries that allow wells to be perforated a considerable distance from the fluid contact. Water drive recovery also depends on the aquifer’s sweep efficiency.
How are water drive reservoirs related to aquifers?
Waterdrive reservoirs Waterdrive (or water drive) petroleum reservoirs are characteristically bounded by and in communication with aquifers. As pressure decreases during pressure depletion, the compressed waters within the aquifers expand and overflow into the petroleum reservoir.
How does a reservoir drive work in an undersaturated reservoir?
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.