Multi-segment wells and well modeling · Outline Introduction to well modeling Multi-segment wells...

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Multi-segment wells and well modeling

Kai Bao

Department of Applied Mathematics, SINTEFkai.bao@sintef.no

OPM meeting, Oslo, June 1st, 2016

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Outline

■ Introduction to well modeling

■ Multi-segment wells

■ Re-factoring of well models

■ Summary

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A typical reservoir simulation procedure

Reservoir WellsReservoir Wells

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Connections

BHP reference depth

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Well related equations

■ For each well we have four primary variables (threephase blackoil model)

■ Mass balance equations

■ Well control equation– BHP control

– Rate control (oil)

Inflow

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Inflow equations

Rate, phase, connection

Connection transmissibility

Mobility

Nodal pressure BHP

Well-bore hydrostatic pressure head

between connection and BHP

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Some of the advantages and limitations

■ Advantages– Relatively simple

– Hydrostatic pressure drop between connections

– Crossflow is described

■ Limitations– A single set of variables for the whole wellbore

– Multilateral wells

– Horizontal wells • friction pressure gradient

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Outline

■ Introduction to well modeling

■ Multi-segment wells

■ Re-factoring of well models

■ Summary

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An example of multilateral well

Part of simulation grid

Well head

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Multi-segment well representationsegment node

flow path

a segment

Top segment

branch junction

Part of simulation grid

BHP reference

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Segment structuresegment node

flow path

a segment

Top segment

outlet segment

Part of simulation grid

BHP reference

inlet segments

Well head

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Well related equations

■ For each segment, we have four primary variables

■ Mass balance equations– For each segment, each phase

Change of phase p in the segment

flow rate from inlet segments

inflow rate from the reservoir

through connections

flow rate towards the outlet segment

inlet segments

outlet segment

Inflow

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Inflow equations

Rate, phase, connection

Connection transmissibility

Mobility

from Eclipse Technical Description

Pcell

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■ Options to calculate the pressure drop– Homogeneous flow model– Built-in 'drift flux' slip model– Pre-calculated Vertical Flow Performance (VFP) table

Pressure equation for each segment

PP-1

hydrostatic pressure drop

friction pressure drop

acceleration pressure drop

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Pressure (control) equation for the top segment

■ The pressure of the top segment is BHP for the well

■ The rates of the top segment are the well rates

■ BHP control

■ Rate control (oil)

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Example 1

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Example 2

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What we can get with multi-segment wells

■ More detailed and fexible well-bore simulation

■ Horizontal and multilateral wells

■ Advanced inflow control devices

■ Pipeline networks

■ Fracturing

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Outline

■ Introduction to well modeling

■ Multi-segment wells

■ Re-factoring of well models

■ Summary

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Originally

BlackoilModel

BlackoilPolymerModel

BlackoilModelBase

Reservoir Wells

Polymer

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Originally

BlackoilModel

BlackoilPolymerModel

BlackoilModelBase

BlackoilMultisegmentModel

Reservoir Wells

PolymerMulti-segment

Wells

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Originally

BlackoilModel

BlackoilPolymerModel

BlackoilModelBase

BlackoilMultisegmentModel

BlackoilPolymer with Multisegment Wells

Reservoir Wells

PolymerMulti-segment

Wells

PolymerMulti-segment Wells

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BlackoilPolymerModel

BlackoilModelBase

Reservoir

Polymer

WellModel

StandardWells

Multisegment Wells

Now

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BlackoilPolymerModel

BlackoilModelBase

Reservoir

Polymer

WellModel

StandardWells

Multisegment Wells

BlackoilModelBlackoilMultisegmentModel

Now

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BlackoilPolymerModel

BlackoilModelBase

Reservoir

Polymer

WellModel

StandardWells

Multisegment Wells

BlackoilModelBlackoilMultisegmentModel

BlackoilPolymer with StandardWells

BlackoilPolymer with Multisegment Wells

Now

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Multi-segment wells + polymer

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Multi-segment well + polymer

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Summary

■ Conventional well model

■ Multisegment wells

■ Refactoring

■ Some features are still yet to be developed– VFP, drift-flux, ICD, etc.

■ Major efforts have been focused on framework development

■ A solid foundation for future development

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Thank You