Production optimization dhbk

Introduction:Production
Optimization
Truc Doan

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Outline
• Introduction
• Well Performance
• Estimated Ultimate Recovery / Reserves
• Well Operations
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•
•
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Remote Booster Compressor (BC)
Blowdown
Well Cycling
Well Unloading Unit (WUU)

• Well Interventions
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•
•
•

Water shut-off
Foam Injection  lifting liquid
Re-perforation  reduce skin

Acid stimulation/ acid wash  reduce skin

• Mechanical Problem


Introduction

Production Optimization = Max rate?

What’s PE concerned?
• Gas Buyer’s nomination?
• Sale target in each funnel?
• Gas rate in each platform/ funnel?
• Reserves of each platform/well?
• any behind pipe?
• Incremental Rate Potential?
• Risk?
• ELU & Slick-Line Unit Scheduling?
• Maximize BC rate?
• CO2/BTU?
• Condensate/ water rate?
Sale Target MDQ = xxx MMscfd

• Water Injection Capacity
• High back Pressure

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Introduction

Production Optimization = Max reserves?

What’s PE concerned?
• Reservoir Management
• Maximize recovery factor
• Reservoir Correlation i.e. best
producer(s)
• Reserves of each platform/well?
• Risk?
• No flow or under performance?
• Time for BC for higher recovery?
• Most of the time  delay
• Single/Commingle sands to
maximize the EUR?

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Introduction

How to Balance Rate vs. Reserves

Max rate

Max reserves

• Meet sale target in short term

• Maximize reserves, less investment

• Less time to W/L move units

• Delay of behind pipe reserves to production

• Risk of water  loss of reserves

• More wells/platforms to operate/maintenance

• More drilling projects, more investment

• More W/L unit move (less efficiency)


Introduction

Typical Gas Well Life Cycle in GOT

Drilling & Completion
Well Intervention

Well Production/ Operation

Time Line

iTTP
Natural Decline

Post-Prod TTP
Operational

Operationalchallenges
challenges

Re-TTP

High Drawdown

WSO

High Water

Cleanout

Fill/ Scale

Put into BC
Cycling
Blowdown
Depleted

Plug and Abandonment


Well Performance

Inflow performance

BHP

• Initial reservoir pressure

Pi

Pres

• Gas being produced,
reservoir pressure and
gas rate decline

VLP

• Reservoir is depleted

Gas rate


Well Performance

Vertical flow performance (no aquifer)
Ppipeline
FTP

Pressure

• Well produce at constant gas rate
• FTP limit at pipeline pressure,
gas rate declines
• Hook the well to BC,
gas rate increase
• Produce at constant

suction pressure, gas
rate declines

BHP

Depth

Pi


Well Performance

Vertical flow performance (with aquifer)
Ppipeline
FTP

FTP

Pressure

• Well produce at constant gas rate
• FTP limit at pipeline pressure,
gas rate declines
• Gas & water mixture is
producing
• Hook the well to BC
• Water start loading
• Water load up

BHP

Water breakthrough the well

Depth

BHP

Pi


Well Performance

Well Test/Well Chart

Log scale

Cum condy

Condy rate
Water rate
Chk size
Gas rate

WGR

Cum gas

THP

Estimated Ultimate Recovery / Reserves

Proved Developed Producing Reserves (P1DP) estimation methods

Rate (log scale)

Rate

EUR
ABN rate

ABN rate

Time

EUR

P/Z

ABN P/Z
EUR

Cum

Cum


Well Operations

Remote Booster Compressor (BC)

• A facility on wellhead platform which enhance gas production and give incremental
reserves by reducing back pressure to about 150 to 250 psi. (lower tubing head
pressure and increase drawdown)

200 psi
500 psi
Well

BC

500 psi
Pipeline (or launcher)


Example: Well X
Natural Flow

BC


Well Operations

Blowdown

• A procedure which intentionally produce the well to flare system (0 psi) for a short
period of time in order to provide maximum drawdown lifting liquid in wellbore and
kick-off production.

Gas to Flare Boom

0 psi
Well

Test Separator

Flare Boom

Liquid to Sump Tank

Sump Tank

Pipeline (or launcher)


Example: Well Y

B/D
B/D


Well Operations

Well Cycling

• A state where a well can be produced periodically by Shut-in and Re-open, then
Shut-in and Re-open again and again in a proper duration.
1500
200
1000psi
psi

psi

200 psi

1500 psi
Open up

Well

Well

Shut in


Example: Well Z
S/I periods

Open periods


Well Interventions

Water shut-off

Pres

DP

Depth

Pressure


Well Interventions

Water shut-off

• Mechanical seal
• Tubing patch
• Tubing plug

• Cement squeeze
• Seal off porous media of target sand

• Polymer/Chemical squeeze
• Change rock permeability


Well Interventions

Water shut-off -> Cement Squeezing

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Shut off produced water

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Repair casing leaks

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Abandon depletes zone

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Selective shut off for water injection

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Seal lost circulation

•

Stop fluid migration

•Fluid Migration


Water shut-off

Example

Before WSO

After WSO


Well Interventions

Foam Injection  lifting liquid

Before inject

After inject

 Reduces the critical velocity of the well
 Enables liquid unloading


Well Interventions

Re-perforation

BHP

Gas rate


Re-perforation

Example

Before re-TTP

After re-TTP


Well Interventions

Acid Stimulation

BHP

Formation damage
Gas rate