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It is based on correlation between surface flowrate 

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bodyq
and bottomhole pressure 
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bodyp_{wf}
as a function of tubing-head pressure 
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bodyp_s
and formation pressure
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bodyp_r
 and current reservoir saturation.


Application

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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 Well Flow Performance (WFP) analysis.Well Flow Performance (


WFP) 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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body\{ p_{wf} \ {\rm vs} \ q \}
cross-plot with two model curves:

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JP
JP

The intersection of IPR and Lift Curves represent the Stabilised wellbore flow (see Fig. 1)

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Given a tubing head pressure 

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bodyp_s
the WFP Junction Point will be dynamic in time depending on current formation pressure (see Fig. 2) and formation saturation (see Fig. 3). 

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Fig. 5. A bunch of IPRs at different formation pressures and Lift Curves at different THPs.


Workflow

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  1. Check the current production rate against the production target from FDP

  2. If the diffference is big enough to justify the cost of production optimization (see point 8 below) then proceed to the step 3 below

  3. Assess formation pressure based on well tests

  4. Simulate IPR / LC based on the current WOR/GOR

  5. Calculate the stabilized flow bottom-hole pressure

  6. Gather the current bottom-hole pressure
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    bodyp_{wf}


  7. Check up the calculation aganst the actual 
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    bodyp_{wf}


  8. Recommend the production optimisation activities to adjust bottom-hole pressure 
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    bodyp_{wf}
    :

    • adjusting the choke at surface

    • adjusting the pump settings from surface 

    • changing the pump depth

    • changing the tubing size

    • changing the pump

The above workflow is very simplistic and assumes single-layer formation with no cross-flow complications.

In practise, the Well Flow Performance (WFP) analysis is often very tentative and production technologists spend some time experimenting with well regimes on well-by-well basis. 


See Also

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Petroleum Industry / Upstream / Production / Subsurface Production / Well & Reservoir Management

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Inflow Performance Relation (IPR) ] [ Lift Curves (LC) ]


  

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WFP
WFP

References

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Joe Dunn Clegg, Petroleum Engineering Handbook, Vol. IV – Production Operations Engineering, SPE, 2007

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