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Definition
WFP – Well Performance Analysis analysis is a comparative Сomparative analysis between:
- the formation the reservoir fluid deliverability (the ability of of reservoir to produce or take-in the fluid) which is called Inflow Performance Relation (IPR)
and
- wellbore fluid deliverability (the ability of of well to lift up or lift down the fluid) and which is called OPR or TPR or VFP (equally popular throughout the literaturecalled Lift Curves (LC) (also called Vertical Lift Performance (VLP) or Tubing Performance Relation (TPR) )
It is based on correlation between surface flowrate
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Application
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- Setting up the required the required production or injection regime for each well upon the current formation pressure, reservoir saturation and production target specified by FDP
- Generating VFP tables as input for 3D simulations Lift Curves (LC) tables as input for Reservoir Flow Modelling (RFM)
Technology
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Most reservoir engineers exploit material balance thinking which is based on long-term well-by-well surface flowrate targets (whether producers or injectors).
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This is primary domain of WFP – Well Flow Performance analysis.
WFP – Well Flow Performance is performed on stabilised wellbore and reservoir flow and does not cover transient behaviour which is one of the primary subjects of Well Testing domain.
The conventional WFP – Well Performance Analysis is perfomed as the
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- Inflow Performance Relation (IPR) – responsible for reservoir deliverability (see below)
- OPR – Outflow Performance Relation ( also called TPR – Tubing Performance Relation and VFP – Vertical Lift Performance Lift Curves (LC) – responsible for for well deliverability (see below )
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The intersection of IPR and OPR curves represent the stabilized flow Lift Curves represent the Stabilised wellbore flow (see Fig. 1)
Fig. 1. The stablised flow rate is represnted as A sample case of stabilised wellbore flow represented by junction point of WFP – Well Flow Performance and OPR curves IPR and Lift Curves. | Fig. 2. The dead well scenario. |
Given a tubing head pressure
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3. A sample case |
of stabilised wellbore flow |
as function of formation pressure. | Fig. |
4.A sample case |
as function |
Fig. 45. A bunch of IPRs IPRs at different formation pressures and TPRs at different THPs Lift Curves at different THPs. |
Workflow
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- Check the current production rate against the production target from FDP
- If the diffference is big enough to justify the cost of production optimization (see point 8 below) then proceed to the step 3 below
- Assess formation pressure based on well tests
- Simulate IPR /OPR based LC based on the current WOR/GOR
- Calculate the stabilized flow bottom-hole pressure
- Gather the current bottom-hole pressure
LaTeX Math Inline body p_{wf} - Check up the calculation aganst the actual
LaTeX Math Inline body p_{wf} - Recommend the production optimisation activities to adjust bottom-hole pressure
:LaTeX Math Inline body p_{wf} - adjusting the choke at surface
- adjusting the pump settings from surface
- changing the pump depth
- changing the tubing size
- changing the pump
- adjusting the choke at surface
The above workflow is very simplistic and assumes single-layer formation with no cross-flow complications.
In practise, the WFP – Well Flow Performance analysis is often very tentative and production technologists spend some time experimenting with well regimes on well-by-well basis.
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OPR – Outflow Performance Relation
OPR – Outflow Performance Relation also called TPR – Tubing Performance Relation and VLP – Vertical Lift Performance represents the relation between the bottom-hole pressure
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p_{wf} = p_{wf}(q) |
which may be non-linear.
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See Also
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Petroleum Industry / Upstream / Production / Subsurface Production / Well & Reservoir Management
Subsurface E&P Disciplines / Production Technology
[ Inflow Performance Relation (IPR) ] [ Lift Curves (LC) ]
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References
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Joe Dunn Clegg, Petroleum Engineering Handbook, Vol. IV – Production Operations Engineering, SPE, 2007
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