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- Setting up the required production or injection regime for each well upon the current formation pressure, reservoir saturation and production target specified by FDP
- Generating WFP – Well Flow Performance tables as input for 3D simulations
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WFP – Well Flow Performance is performed on stabilised wellbore and reservoir flow and does not cover transient behavior behaviour which is one of the primary subjects of Well Testing domain.
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| title | More on stabilised reservoir and wellbore flow |
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The wellbore flow is called stabilised if the delta pressure across wellbore is not changing over time.
The formation flow is called stabilised if the well productivity index is not changing over time.
It's important to remember the difference between constant rate formation flow and stabilised formation flow.
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On the other hand, the constant rate formation flow may not represent a stabilised formation flow as the bottom-hole pressure and productivity index maybe still in transition after the last rate change.
The WFP methods are not applicable if the well flow is not stabilised even if the flow rate is maintained constant.
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The pseudo-steady state (PSS) regime is reached when the flow is stabilised with no pressure support at the external boundary.
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As for formation and bottom-hole pressure in PSS they will be synchronously varying while in SS they will be staying constant.
The table below is summarizing the major differences between SS and PSS regimes.
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constant
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constant
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constant
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constant
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Drawdown
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constant
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constant
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constant
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varying
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constant
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varying
It's again important to avoid confusion between the termines stationary conditions (which mean that refered properties are not chaning in time) and stabilised flow conditions which may admit pressure and rate vraition.
In practice, the productivity index is usually not known at all times as there is no routine procedure to assess it.
It is usually accepted that a given formation takes the same time to stabilise the flow after any change in well flow conditions and the stabilisation time is assessed based on the well tests analysis.
Although, this is not strictly true and the flow stabilisation time depends on well-formation contact and reservoir property variation around a given well.
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The conventional WFP – Well Performance Analysis is perfomed as the
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