Maximum height of an oil column in cap rock depends on several factors, including the properties of the cap rock (such as its capillary pressure and permeability), the density difference between the oil and the water in the reservoir, and the strength of the sealing mechanism. This height is often referred to as the hydrocarbon column height or trap capacity, which represents the vertical distance from the oil-water contact to the top of the oil column that the cap rock can retain without leaking.
Maximum Height of Oil Column in Cap Rock Formula |
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| \( h \;=\; \dfrac{ P_a - P_w + G_o \cdot h \cdot \alpha + p_c }{ \rho - G_o }\) | ||
| Symbol | English | Metric |
| \( h \) = Maximum Height of Oil Column | \(ft\) | - |
| \( P_a \) = Total Potential Energy of Accumulation (psi) | \(lbf\;/\;in^2\) | - |
| \( P_w \) = Water Potential in Reservoir (pis) | \(lbf\;/\;in^2\) | - |
| \( G_o \) = Initial Oil Pressure Gradient in Reservoir Rock | \(in^2\) | - |
| \( \alpha \) = Height Constant | \(dimensionless\) | - |
| \( h \) = depth | \(ft\) | - |
| \( p_c \) = Capilary Pressure (psi) | \(lbf\;/\;in^2\) | - |
| \( \rho \) (Greek Symbol rho) = Density Differential between Fluids | \(ppg\) | - |
Maximum Height of Oil Column in Cap Rock Formula |
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| \( h \;=\; \dfrac{ p_c }{ \Delta \rho \cdot g }\) | ||
| Symbol | English | Metric |
| \( h \) = Maximum Height of Oil Column | \(ft\) | - |
| \( p_c \) = Capillary Pressure of the Cap Rock (the Pressure Required to Force Oil Through the Smallest Pores of the Cap Rock) | \(lbf\;/\;in^2\) | - |
| \( \Delta \rho \) = Density Difference between Water and Oil | \(lbf\;/\;in^2\) | - |
| \( g \) = Gravitational Acceleration | \(ft\;/\;sec^2\) | - |
