Outflow 18/04/02 Outflow.ppt, page 1P180

How do we get hydrocarbons to surface?

What is tubing performance?

How do we size tubing?

Outflow 18/04/02 Outflow.ppt, page 2P180

At the end of this session you should be able to:

• Explain what tubing performance is

• Describe the key features of tubing performance

• Carry out a tubing size selection exercise

Outflow 18/04/02 Outflow.ppt, page 3P180

• Just as we optimise the Inflow performance of flow from the reservoir to the wellbore, we also need to optimise the Outflow performance from the bottom of the well to surface

• Tubing performance is the term used to describe Outflow performance. It is also called Vertical Lift Performance

• Tubing Performance looks at optimising/minimisingpressure losses at lowest life cycle cost. By minimisingpressure drop, we maximise production.

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• In order to flow from the bottom of the well to surface, we need to overcome several pressure drops

– Hydrostatic head– Frictional losses– Acceleration effects

(normally negligible)

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• Bubble flow - dispersed bubble of gas in continuous liquid phase;

• Slug flow - coalescing bubble in larger one, expanding across the entire pipe x-section. Between the larger bubble are slugs of liquid with entrained smaller gas bubbles

• Churn flow - highly turbulent flow pattern and dispersion of both gas- and liquid phase

• Annular flow (mist flow) - gas is continuous phase, with dispersed liquid droplets; liquid moves as (unstable) boundary layer to the pipe;

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INCREASE of PWF due to fluid hold-up

INCREASE of PWF due increasing friction

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• Flowing tubing pressure

• Length of tubing

• Friction factors

• Tubing diameter

• Fluid composition (liquid/gas)

Outflow 18/04/02 Outflow.ppt, page 11P180

Flow

ing

botto

mho

lepr

essu

re P

WF

Flow rate (Q)

THP1

THP2

THP1 > THP2

Outflow 18/04/02 Outflow.ppt, page 12P180

Flow

ing

botto

mho

lepr

essu

re P

WF

Flow rate (Q)

5”

4”

2 7/8”

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Flow

ing

botto

mho

lepr

essu

re P

WF

PWF

GLR1

GLR3

GLR2

Flow rate (Q)

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• IPR - Inflow Performance Relationship

• IPC - Intake Pressure Curve

• TPC - Tubing Performance Curve

• CPC - Choke Performance Curve

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• To isolate the well from downstream pressure

• Control of downhole pressure

QPfwh PFLD2 P (D ) Qfwh = 2 , GLRf

Critical flow:

Single -phase gas flow : PFTH > 1.9 PFL

Multi-phase gas-liquid flow : PFTH > 1.7 PFL

D1

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• Tubing performance is the term used to describe Outflow performance.

• Tubing performance dependent on:– Flowing tubing pressure – Length of tubing– Friction factors– Tubing diameter– Fluid composition (liquid/gas)

• Definition of terms

• Use of Choke

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In your syndicate groups, please do the following:

• Explain what tubing performance is

• What are IPC, TPC & CPC

• Describe the key parameters which tubing performance -what are they & how do they affect tubing performance

1

© 1999 Shell International Exploration & Production BV Outflow2.ppt, page 1 P180

Pressure Losses in Oil Production.

2

© 1999 Shell International Exploration & Production BV Outflow2.ppt, page 2 P180

The Function of a Completion

3

© 1999 Shell International Exploration & Production BV Outflow2.ppt, page 3 P180

Dual Completion

4

© 1999 Shell International Exploration & Production BV Outflow2.ppt, page 4 P180

Representation of Flowing Well