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Geology/Reservoir engineeing terms


Thanks Keith for your time for helping every body.

Please tell me the meanings of Bubble Point, Dew point, Abandoning pressure  and Reservoir pressure.

What is Formation Volume factor (FVF) and how it can be calculated for volumetrics calculation for oil and gas reserves.

Thanks in advance.



Most of these should be available in your textbook or glossary of terms.

Bubble point is the pressure in a reservoir at which gas begins to bubble out of the petroelum, condensate and brine solution.  At this time the gas expands driving the oil to the surface.

Dew Point  (pressure) is the pressure at which liquid begins to drop out of the gas phase in a reservoir.  

The relationship between the bubble point, dew point and critical point are described by a phase diagram with X Temperature and Y Pressure.

Abandonment Pressue is simply the minimum pressure messured in a reservoir when the wells are abandoned.

Reservoir Pressure:  The pressure of fluids within the pores of a reservoir, usually hydrostatic pressure, or the pressure exerted by a column of water from the formation's depth to sea level. When impermeable rocks such as shales form as sediments are compacted, their pore fluids cannot always escape and must then support the total overlying rock column, leading to anomalously high formation pressures. Because reservoir pressure changes as fluids are produced from a reservoir, the pressure should be described as measured at a specific time, such as initial reservoir pressure.

Formation volume Factor  Oil and dissolved gas volume at reservoir conditions divided by oil volume at standard conditions.

Since most measurements of oil and gas production are made at the surface, and since the fluid flow takes place in the formation, volume factors are needed to convert measured surface volumes to reservoir conditions (reserves). Oil formation volume factors are almost always greater than 1.0 because the oil in the formation usually contains dissolved gas that comes out of solution in the wellbore with dropping pressure.

For a discussion of volumetrics calculation including FVF  see here:  


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Keith Patton


I can answer questions concerning physical and historical geology, environmental geology/hydrology, environmental consulting, remote sensing/aerial photo interpretation, G&G computer applications, petroleum exploration, drilling, geochemistry, geochemical and microbiological prospecting, 3D reservoir modeling, computer mapping and drilling.I am not a geophysicist.


I have 24 years experience split between the petroleum and environmental industries. I have served as an expert witness in remote sensing, developmental geologist, exploration geologist, enviromental project manager, and subject matter expert in geology and geophysical software development.

American Association of Petroleum Geologists
American Association of Photogrammetrists and Remote Sensing

Bachelor and Master of Science
Registered Geologist in State of Texas

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