Modelling facility for field-average formation pressure at any time moment as response to production flowrates history:
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where
cumulative offtakes from -th producer by the time moment | |||
cumulative intakes to -th injector by the time moment | |||
effective formation thickness averaged over drainage area | full-field cumulative offtakes by the time moment | ||
effective porosity as function of formation pressure | full-field cumulative intakes by the time moment | ||
total compressibility as function of formation pressure | full-field cumulative volumetric inflow from gas cap expansion | ||
full-field cumulative reservoir fluid balance | full-field cumulative volumetric inflow from aquifer expansion |
and which is often completed by constant PI model of Bottom-Hole Pressure ( for producers and for injectors):
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where
productivity index of -th producer | |||
injectivity Index of -th injector |
In practice there is no way to measure the external influx and so that one need to model them and calibrate model parameters to fit available data on production flowrates history and formation pressure data records.
There is a list of various analytical aquifer and Gas Cap drive models which are normally based on the relations:
Gas Cap Expansion @model | Aquifer Expansion @model | ||
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In some specific cases equation can be explicitly integrated:
Low compressibility rocks and fluids | Ideal dry gas | ||
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where
drainage volume |
Petroleum Industry / Upstream / Production / Subsurface Production / Field Study & Modelling / Production Analysis
Material Balance Analysis (0D or MatBal)