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