Motivation
The most accurate way to simulate Gas Cap expansion (or shrinkage) is full-field 3D Dynamic Flow Model where Gas Cap expansion is treated as one of the fluid phases and accounts of geological heterogeneities, gas fluid properties, relperm properties and heat exchange with surrounding rocks. Unfortunately, in many practical cases the detailed information on the Gas Cap is not available. Besides many practical applications require only knowledge of one element of the Gas Cap expansion process – a pressure support and not the sweep in the invaded zones. This allows building a Gas Cap Drive @model using analytical methods.
Inputs & Outputs
Inputs | Outputs | ||
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p(t) | field-average formation pressure at time moment t | Q^{\downarrow}_{GC}(t) | Cumulative subsurface gas influx from Gas Cap |
p_i | Initial formation pressure | \displaystyle q^{\downarrow}_{GC}(t) = \frac{dQ^{\downarrow}_{GC}}{dt} | |
V_{gi} | Initial Gas Cap volume | ||
Z(p) | Gas compressibility factor |
Physical Model
Isothermal expansion | Uniform pressure depletion in Gas Cap |
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T = \rm const | p_{GC}(t) = p(t) |
Mathematical Model
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Proxy Models
Ideal Gas ( Z=1) | |||||
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In this case the only parameter of the gas cap model is its initial volume V_{gi} |
See Also
Petroleum Industry / Upstream / Subsurface E&P Disciplines / Field Study & Modelling / Gas Cap Drive
[ Depletion ] [ Saturated oil reservoir ]