Alcino R. Almeida - CENPES

Guilherme A. Peixoto - UN-BCJosé Eduardo Mendonça - UN-RIOPaulo José P. Ribeiro - EP-CORP

PETROBRAS Deepwater Gas Lift Project(an overview)

PETROBRAS Deepwater Gas Lift Project(an overview)

ASME/API/ISO Spring 2005 Gas-Lift Workshop

Rio de Janeiro - February, 2005

Objective

- Search for products that will optimize gas liftprocess in high pressure and high flow rate deepwater subsea wells

- The Deepwater Gas Lift Project is part of a major PETROBRAS Technological Program

- PROCAP 3000 -

Deepwater Gas Lift Project Schedule:

Phase I : Feb, 1999 to Feb, 2005

Phase II : Mar, 2005 to Jul, 2006

PHASE I : AREAS OF INTEREST

1 – Scenario Studies

2 – Gas Lift Equipment Development

3 – Gas Lift Software Development

4 – Gas Lift Automation

Scenario StudiesScenario Studies

Production Methods – Campos Basin

Number of Wells

7015%

29563%

10422%

FLOWING CONTINUOUS GL ESP

Production Methods – Campos Basin

Flow Rate

36%

59%

5%

FLOWING CONTINUOUS GL ESP

FocusFocus in Campos in Campos BasinBasin FieldsFields::

1 – Roncador

2 – South Marlim

SCENARIO STUDIES

SCENARIO STUDIES

Main Oilfield Data:

Datum: - 2500 to - 3200 m

Water Depth: 1000 to 3000 m

Well to Platform distance: 1.5 to 12 km(1 to 7.5 mi)

Oil Specific Gravity: 12 to 30 οAPI

Bottom Hole Pressure: 250 to 290 bar(3600 to 4200 psi)

Productivity Index: 10 to 100 m3/d/bar(4.5 to 45 bpd/psi)

Formation GOR: 50 to 75 m3/m3

(280 to 420 scf/bbl)

Points to inject lift gas

1 - downhole

2 - at the Subsea Well Head

3 - at riser base

GL points

Where is the best GL injection point ?

0

500

1000

1500

2000

2500

3000

0 0,1 0,2 0,3 0,4 0,5 0,6 0,7 0,8 0,9 1

Water Depth / Datum

Liq

uid

Flow

rate

(m

3/d)

riserwhcpoço

Depends on BHP, Flow Line Lenght, PI, ....

-EXAMPLE-

WD = 2000 mWD = 1500 m

Reservoir Datum = 2500 m

What is the best type of operating valve ?

Venturi X Orifice Gas Lift Valves

0

2

4

6

8

10

12

Π−01 Π−03 Π−09 Π−1 3 Π−1 5 Π−1 9 Π−2 1 Π−23 ΡΟ−08 ΡΟ−09 ΡΟ−12 ΡΟ−14 ΡΟ−1 6 ΡΟ−1 7 ΡΟ−1 8 ΡΟ−19 ΡΟ−21 ΡΟ−24 ΡΟ−2 5 ΡϑΣ−4 3 6

Wells

Oil

Flow

rate

Incr

ease

(%)

What is the best type of IPO GL valve ?

High Pressure X Conventional IPO Valves

0

2

4

6

8

10

12

14

P- 0 1 P- 0 3 P- 0 9 P- 13 P- 15 P- 19 P- 2 1 P- 2 3 RO- 0 8 RO- 0 9 RO- 12 RO- 14 RO- 16 RO- 17 RO- 18 RO- 19 RO- 2 1 RO- 2 4 RO- 2 5 RJS- 4 3 6

Poços

Oil

Flow

rate

Incr

ease

(%)

Operational flexibility:

– Reduce the number of GL valves

– Prevent instabilities and severe slug

– Easy way to start up the well

Single point injection in ultradeep wells

Advantages of Subsea Injection Gas Points

Equipment DevelopmentEquipment Development

EQUIPMENT DEVELOPMENT

New GL valves

– Venturi

– High pressure IPO

– Normally Open Valve

– Electric GL valve

PETROBRAS Gas Lift Valve Test Site(Aracaju-SE)

Dynamic Performance and Endurance Tests

Development of New Gas Lift Valves

– Venturi type valves

• Intensively bench and field tested byPetrobras

• Standard valve in Petrobras deepwaterwells

• Petrobras patented valve is beingmanufactured in Brasil

Venturi Valves Performance

0

10000

20000

30000

40000

50000

60000

70000

80000

90000

0 500 1000 1500 2000 2500

Downstream Pressure (psig)

Gas

Flo

wra

te (m

³/d)

Venturi Gas Lift Valve 1 1/2"

Petrobras ValveManufacturer Valve

– 3000 psi Gas Lift Valve• Developed under a Cooperation Agreement

• Allows deeper operation injection point

• Bench tested

• Field test: one valve is operating in Albacora field since July, 2003

Development of New Gas Lift Valves

High Pressure Bellows Valve Performance

C-R20H-16Tg-SSG12030-2000

09000

18000270003600045000540006300072000810009000099000

100 400 700 1000 1300 1600 1900 2200PT-M2 (psig)

VAZÃ

O (N

m³/d

)

Nível 1Nível 2Nível 3Nível 4Nível 5

– Electric Gas Lift Valve• Petrobras was a member of a JIP with other

operators and one manufacturer

• Field tested in the USA (Simpson Field, Indiana) in 2001

• High cost => not attractive for standard applications

Development of New Gas Lift Valves

- Normally Open Gas Lift Valve– opens with low injection casing pressure

– closes with high injection casing pressure

– failed in field test in Campos Basin in 2001 (Cherne field)

– endurance tests in Atalaia Test Site in 2004 showed a need for further improvement

– Application scenario:

• as an operating valve (dual compression sites)

• as a kickoff valve

Development of New Gas Lift Valves

Development of New Gas Lift Valves

NormallyOpen Gas Lift Valve

Problems

detected

PETROBRAS GAS LIFT TEST SITE

PERFORMANCE TESTS

ENDURANCE TESTS

PETROBRAS GAS LIFT TEST SITE

Software DevelopmentSoftware Development

MARLIMMARLIM

(Multiphase and Artificial Lift Modelling)

– In-house and continuous development

– Accurate Pressure and Temperature profilesprediction in multiphase flow

– Used to design and troubleshooting analysis

– Includes dynamic performance of GL valves

Steady State Software

Temperature Profiles Comparison

0

500

1000

1500

2000

2500

3000

35000 4 8 12 16 20 24 28 32 36 40 44 48 52 56 60 64 68 72

Temperature (C)

Dep

th (m

)

Test 03/01/1999MarlimSimulator ASimulator B

– Calculate transient temperature and pressure

profiles (production and annular systems) in multiphase flow

– Useful for kickoff and design analysis with natural gas or

nitrogen injection and including coiltubing if necessary

– Dynamic Performance of GL valves and chokes are included

Two softwares are being developed by Petrobras:

- FLOWLIFT – with external consultant

- TRACELIFT – specific presentation will be made at GL

workshop

Transient Softwares

Transient Software

System geometry

Fluids:– oil + formation water– Formation gas– Natural gas as lift gas– Nitrogen as lift gas– Completion fluid during

kickoff

Flowlift - Example

0 4000 8000 12000 16000tempo

0

1

2

vazã

o de

gás

vazão de gás - válvula 1

vazão de gás - válvula 2

0.0

0.5

1.0

aber

tura

Automation and Phase II of the ProjectAutomation and Phase II of the Project

Goals:

Optimization and automation of gas allocation per well

Automatic instabilities control

Specific presentation on the subject in this Workshop

Gas Lift Automation

A low cost alternative for automation without depending on well interventionThe optimum injection point may be inferred from the surface temperatureTemperature is proportional to the flow rate (simulation results)Keep GL optimized all the time

0 20000 40000 60000 80000Injeção de lift gas (Sm3/d)

920

940

960

980

1000

1020

Vaz

ão d

e líq

uido

(Sm

3/d)

36

37

38

39

Tem

pera

tura

do

fluid

o a

mon

tant

e do

cho

ke (g

rau

C)

t_behavi.grf

84.8

84.9

85.0

85.1

85.2

Tem

pera

tura

do

fluid

o na

AN

M (g

rau

C)

Legenda

temp. no coletor

temp. na ANM

vazão de líquido

Surface temperatureX-tree temperatureLiquid flow rate

GL Automation by Temperature

GL Automation by Temperature

Delay analysis chart

0

10

20

30

40

50

602:

53:2

3 PM

3:00

:39

PM3:

07:5

6 PM

3:15

:14

PM3:

22:2

9 PM

3:29

:47

PM3:

37:0

6 PM

3:44

:21

PM3:

51:3

5 PM

3:58

:49

PM4:

06:0

5 PM

4:13

:19

PM4:

20:3

3 PM

4:27

:47

PM4:

35:0

2 PM

4:42

:17

PM4:

49:3

2 PM

4:56

:45

PM5:

04:0

1 PM

5:11

:16

PM5:

34:4

6 PM

5:42

:03

PM5:

49:2

0 PM

5:56

:36

PM6:

03:5

1 PM

6:11

:07

PM6:

18:2

3 PM

6:25

:37

PM6:

32:5

2 PM

6:40

:07

PM6:

47:2

3 PM

6:54

:38

PM

Time

Flow

rate

[m3/

h]

35.5

36

36.5

37

37.5

38

38.5

39

39.5

40

40.5

41

Tem

pera

ture

[oC

]

voleotoleo

GL Automation by Pressure

SUPERVISORY INFORMATIONSUPERVISORY INFORMATION

Gas Lift Riser Base Injection

Erosional Velocity – Bench Tests in Atalaia

New Venturi Developments

PHASE II : AREAS OF INTEREST