Frac-pack in Ultra Deep Water

SPE DISTINGUISHED LECTURER SERIESis funded principally

through a grant of the

SPE FOUNDATIONThe Society gratefully acknowledges

those companies that support the programby allowing their professionals

to participate as Lecturers.

And special thanks to The American Institute of Mining, Metallurgical,and Petroleum Engineers (AIME) for their contribution to the program.

Frac-pack in Ultra Deep Water: Lessons Learned from a Hundred of

Well Succeeded Operations

Carlos A. Carlos A. PedrosoPedroso

Also thanksAlso thanks to Petrobrasto Petrobras

3

OutlinesCampos Basin scenario & Sand control evolutionCampos Basin scenario & Sand control evolutionHigh productivity High productivity fracpacksfracpacks: lessons learned: lessons learned

Best practices for high productivity wells in high Best practices for high productivity wells in high permeability sandstonespermeability sandstonesSpecific deep water issuesSpecific deep water issuesChallenges in deep water, soft rock fracturing Challenges in deep water, soft rock fracturing

Importance of TSO Importance of TSO How to obtain the planned TSOHow to obtain the planned TSO

Data collectionData collectionCorrect AnalysisCorrect Analysis

Design and operational questionsDesign and operational questions

ConclusionsConclusions

4

Introduction

Campos Basin Scenario:

- Clean, high-permeability (300 to 14,000 mD) sandstones

- From poorly consolidated to unconsolidated sandstones

- Medium to heavy oil (29 to 14 API)

- Water depths ranging from 40 m (130 ft) to 2000 m (6500 ft)

5

Introduction

1988 1988 PROCAP “1000”PROCAP “1000”

19931993PROCAP 2000PROCAP 2000

20002000PROCAP 3000PROCAP 3000

6

DEPTH

COST

NEED FOR PRODUCTIVITY

7

Introduction

Deep water

High permeability

Unconsolidated Sands

ScenarioScenario PossiblePossible

SolutionsSolutionsOHHGP OHHGP –– 200 200 installationsinstallations

CHFP CHFP –– 130 130 installationsinstallations

NeedsNeeds

Sand Control

High Productivity

Durability

(( decdec 2

006)

2006

)

8

Primary option for all vertical/deviated wells, except:Primary option for all vertical/deviated wells, except:Oil/Water or Gas/Oil contact Oil/Water or Gas/Oil contact Mechanical constraints (casing, cementing,..) Mechanical constraints (casing, cementing,..)

In the past: “Can I fracpack?” In the past: “Can I fracpack?” Today: Today: ““How can I fracpack?How can I fracpack?””

Special mechanical cares: Special mechanical cares: The need of special toolsThe need of special tools

Larger volumesLarger volumesAggressive proppant rampsAggressive proppant ramps

Frac pack became…

9

Well succeeded fracpack(FRACPACK DEFINITION)

Low skin Low skin Best practicesBest practices

High conductivity fracturesHigh conductivity fractures TSO as plannedTSO as planned

No remedial acid jobs No remedial acid jobs BothBoth

No sand production No sand production Proper sand control designProper sand control design

10

Well succeeded fracpackSkin (Buildup & Falloff Test)

10

22

10

8

6

4

65

32

1

4

0

5

10

15

20

25

<0 0-1 1-2 2-3 3-4 4-5 5-10

10-15

15-20

20-30

30-40 >4

0

Skin

Num

ber o

f wel

ls

75%

From 1995 to 2005 (71 wells tested)From 1995 to 2005 (71 wells tested)

11

Best (good) practices HSC Overbalance x TCP HSC Overbalance x TCP UnderbalanceUnderbalance

Clean up flow prior to fracturingClean up flow prior to fracturing

AcidizingAcidizing prior to fracturingprior to fracturing

Riser and casing cleaningRiser and casing cleaning

Internal coated work string cleaningInternal coated work string cleaning

Brine FiltrationBrine Filtration

Gel and proppant quality Gel and proppant quality

Well k(mD)

s DR Perforating

A-1 354 1.9 1.3 Overbalanced


A-3 70 -1.5 0.8 Underbalanced

A-4 460 13.9 2.7 Underbalanced




XX

12

Perforations HSC overbalance x TCP underbalance

13

Perforations

Underbalance745.26600A7-UBOverbalance6.710.22795A6-OBOverbalance1.11.61516A2-OB

Underbalance1.63.9860A5-UBUnderbalance2.713.9460A4-UBOverbalance1.31.9354A1-OB

Underbalance0.8-1.570A3-UBPerforationDRSkinK (mD)Well

Field “A”, same reservoir, equivalent operational conditions Field “A”, same reservoir, equivalent operational conditions (1997 to 1999) (1997 to 1999)

14

-10

0

10

20

30

40

50

A3-UB A1-OB A4-UB A5-UB A2-OB A6-OB A7-UB

Skin

e D

amag

e R

atio

1010

010

0010

000

Perm

eabi

lity

SkinDRK (mD)

OB OB

OB

Perforating Type x Skin & Damage Ratio

UBUB

UBUB

UBUB

UBUB

15

Acidizing prior to fracturingMain objective: clean perforationsMain objective: clean perforations

(BHP Data)

16

Workstring cleaning

Solvent and/or picklingSolvent and/or pickling

17

Casing and riser cleaning

18

Stimulation boat, gel and proppant

Frac pack requires Frac pack requires specifically designed specifically designed equipmentequipmentThe proppant control must The proppant control must be automatedbe automatedHSP (Synthetic) x SandHSP (Synthetic) x Sand

Gel mixed onGel mixed on--thethe--fly using fly using sea watersea waterEnzymatic breakerEnzymatic breakerVirtually no damage related Virtually no damage related to the gel systemto the gel system

(SPE – 73722)

19

CostCostStatisticStatisticGood practiceGood practice

MEDIUMMEDIUMYESYESGel and Gel and proppantproppant quality quality MEDIUMMEDIUMNONOBrine FiltrationBrine Filtration

LOWLOWNONOInternal coated work Internal coated work string cleaningstring cleaning

LOWLOWNONORiser and casing cleaningRiser and casing cleaning

LOWLOWNONOAcidizingAcidizing prior to prior to fracturingfracturing

HIGH HIGH (*)(*)YESYESClean up flow prior to Clean up flow prior to fracturingfracturing

HIGH HIGH (*)(*)YESYESHSC Overbalance x TCP HSC Overbalance x TCP UnderbalanceUnderbalance

(*) +(*) +US$ 1,500,000/well due to OB (HSC) perforationUS$ 1,500,000/well due to OB (HSC) perforation

20

BEST (GOOD) PRACTICES

-200

300

800

1,300

1,800

2,300

2,800

C-1

E-1

A-2

G-2

A-4

M-1

E-2 F-1

F-2

G-4 J-1

F-3

A-7

C-2

C-3 J-3

H-2

B-4

B-6

G-7

B-9

P-1

B-10 I-2 N-1

A-8

B-13 G-9

Dra

w D

own

(psi

)

SPE – 73722

21

Deep Water Specific Issues

•High depths with low sediments•Low frac gradients

•Low elastic modulus

•Cooling of injected fluids (4 C @ sea bed)•Increase of frac fluid efficiency

•Breakers test temperature: -20 F to -50F

•DP rig and boats (strict and written procedures)

•Hydrates (prevention is better than remediation)

22

Design issuesDesign issuesTip Screen Out (TSOTip Screen Out (TSO) is mandatory ) is mandatory

Data collectionData collectionRock Mechanics Rock Mechanics

Calibration testCalibration test

Height growth Height growth

Well DeviationWell Deviation What is a TSO ?What is a TSO ?

23

Tip Screen Out (TSO) is mandatory

Four scenarios for fracpack:Four scenarios for fracpack:The BestThe Best: TSO happens and the fracpack is pumped as : TSO happens and the fracpack is pumped as planned, with planned net pressure gainplanned, with planned net pressure gainAcceptableAcceptable: TSO happens but it is followed by a : TSO happens but it is followed by a premature screen out, with lower premature screen out, with lower –– or higher or higher -- net pressure net pressure gaingainBad oneBad one: TSO does not happen: TSO does not happenWorst oneWorst one: TSO does not happen and a premature screen : TSO does not happen and a premature screen out occurs out occurs

SPE – 73722

24

TSO is the key factor !We can stand premature screen out after a TSO even with We can stand premature screen out after a TSO even with

little net pressure gain (low E. high little net pressure gain (low E. high νν))(No remedial acid jobs were performed when TSO was obtained)(No remedial acid jobs were performed when TSO was obtained)

2

1 4

4(1 )( ,0, ) ( , )

' net

vW x t H p x tE

QLW H pEμ

−≈ Δ

⎛ ⎞∝ ∝ Δ⎜ ⎟⎝ ⎠

26.0100ZeroNC-318.0100ZeroNB-521.967ZeroNB-44.8291100YG-14.220450YB-8-0.7100300YB-61.6551050YA-21.988370YA-1

SkinProp (%)

∆Pnet(psi)TSOWell

25

Reliable data collection Correct Analysis Skilled planning

TSO is the key factor…

……but it’s not easy !but it’s not easy !

26

Reliable data Rock Rock ppropertiespproperties

Reliable elastic Reliable elastic modulimoduliMinimum stress directionMinimum stress direction

Imaging fractureImaging fractureOriented Cores Oriented Cores

VelanVelanASRASR

Leak off dataLeak off dataCalibrationCalibration testtest

Surface pressure x BHPSurface pressure x BHPLive annulus pressureLive annulus pressureOn site analysisOn site analysis

27

Elastic Moduli

Simplified ModelSimplified Model ““More realistic” ModelMore realistic” Model

28

Usual simplifications Probable results

““Planned”Planned”FractureFracture

ObtainedObtainedFractureFracture

29

With…Inverted stress

GoodGood

Data !!!Data !!!

Elastic properties

30

Reliable data Reliable elastic Reliable elastic modulimoduliMinimum stress directionMinimum stress direction


VelanVelanASRASR

CalibrationCalibration testtestSurface pressure x Surface pressure x BHPBHPLive annulus Live annulus pressurepressureOn site analysisOn site analysis

Cross Dipolar Sonic Log Cross Dipolar Sonic Log

31

Minimum stress direction•• Imaging after XLOTImaging after XLOTBefore

32

VELAN - Velocity Anisotropy0

10 2030

40

50

60

70

80

90

100

110

120

130

140150

160170180

190200210

220

230

240

250

260

270

280

290

300

310

320330

340 350

σHmax

σhmindireção de

diminuição de VPLower Lower VpVp

33

Minimum stress

Normal faults

ASRASR

VelanVelan

34

Reliable data Reliable elastic Reliable elastic modulimoduliMinimum stress directionMinimum stress direction


VelanVelanASRASR

CalibrationCalibration testtest

Surface pressure x BHPSurface pressure x BHP

Live annulus pressureLive annulus pressure

On site analysisOn site analysis

35

Calibration TestCalibration tests , with in situ analysis, are a needFET, 1 or 2 Minifracs, SDT, SRTMinifrac, with BHP, is always performedSRT,

To confirm feasibility of treatment To help to restore pre-minifrac leak-off valuesAs primary evaluation of Pc

FETPrimary evaluation of Pc

SDTWell to formation connectivity

Minifrac AnalysisImportance of BHP for high permeability

3.140.10.00413.5438.90.00313.42A-37.524.40.0025.9222.70.0045.06A-4

15.78.10.0251.187.00.0180.43A-5300.06.80.0620.561.70.0930.12A-7-57.35.60.2130.6413.10.0731.23A-122.23.30.0460.202.70.0860.13A-6-59.12.70.0910.266.60.0480.90A-2

%%ft√min(min)%ft√min(min)ErrorEfCtTcEfCtTcWell

BH data Surface data (DP)

37

Live Annulus DataBHP data from live annulus is very close to BHP BHP data from live annulus is very close to BHP data from electronic gaugesdata from electronic gauges

38

Non ideal pressure declinein soft rock

Tip extensionTip extension

Pressure dependent leak offPressure dependent leak off

Height recession Height recession

39

TipExtension

40

Pressure Dependent

Leakoff

Low KLow K

High KHigh K

Low KLow K

High KHigh K

41

Height Recession

42

Temperature logs

Height growHeight grow

43

Temperature Logs

44

Thick, deviated interval Perforation: 2761Perforation: 2761--2830 (69m)2830 (69m)Inclination: 64Inclination: 64o o

Net pay: 30.5mNet pay: 30.5mLimited entry perforation prior to mf Limited entry perforation prior to mf Minifrac: 25 Minifrac: 25 bpmbpm

45

Thick, deviated interval

46

Correct analysis helped by temperature logThick, deviated interval

47

Skilled design

••Multiple intervalsMultiple intervals

••Thin intervalsThin intervals

••Highly deviated wellsHighly deviated wells

••Restricted perforationRestricted perforation

Pseudo 3D Models

48

Planned ... Obtained

49

Frac pack in thin sand with high-permeability

Thin sand, highThin sand, high--permeability:permeability:–– Low complianceLow compliance–– High leakoffHigh leakoff–– Narrow fracturesNarrow fractures

Low conductivityLow conductivityBetter results with Better results with HRWPHRWP

Well TVD (ft) Fluid DR [Prop] I-1 16.4 Gel 3.3 10

G-12 17.7 Water 1.5 1 G-13 10.5 Water 1.2 1-2 J-5 16.4 Water 1.3 1-2 M-3 19.7 Water 1.7 1-2

50

Stress anisotropy

Field MField M--22

••Completely unconsolidated Completely unconsolidated

••Permeability > 2,000 Permeability > 2,000 mDmD

••UCS < 200 UCS < 200 psipsi

••E < 400,000 E < 400,000 psipsi

StressStress

IsotropyIsotropy

ExpectedExpected

51

• 2 stacked fracpacks – 3470/3490 m (TVD – 2645/2656 m)

3435/3455 m (TVD – 2627/2637 m)

• PI – 31 (m3/d/kg/cm2)

• DR – 2.9

5 m shale (MD) - 2.6 m TVD

Deviated well – 58 Grades

52

Vertical well

• Interval -2671/2718 m

• PI – 133 (m3/d/kg/cm2)

• DR – 1.1

53

Highly deviated well

2.832.831.471.47SpecifSpecif PI PI ((m3/d/kg/cm2/mm3/d/kg/cm2/m))

2500/15002500/15001442/8831442/883ProdProd rate (rate (total/oiltotal/oil) () (m3/daym3/day))270027001430/14301430/1430ProdProd Rate (Rate (total/oiltotal/oil) () (m3/daym3/day) ) 1.11.12.92.9DRDR

1331333131PI (PI (m3/d/kg/cm2m3/d/kg/cm2))zerozero5858InclinationInclination ((grgr))474711 + 1011 + 10TVD TVD perforationperforation (m)(m)535320 + 20 20 + 20 MD MD perforationperforation (m)(m)1122FracpackFracpackVerticalVerticalDeviatedDeviated

54

Restricted PerforationRestricted Perforation

Aug/2006 12 operations well suceeded

55

Next steps

Fully 3D simulationFully 3D simulation

Green FPGreen FP

Multiple zones in one tripMultiple zones in one trip

56

Conclusions

The perforation method, OVB or UND, with or The perforation method, OVB or UND, with or without clean up flux has little importance to the without clean up flux has little importance to the final results of a well done/well designed fracpackfinal results of a well done/well designed fracpack

TSO is the key for a successful fracpack in highTSO is the key for a successful fracpack in high--permeability formations. permeability formations.

Reliable data, calibration test, BHP data and Reliable data, calibration test, BHP data and in situ in situ design is the key for high permeability fracturingdesign is the key for high permeability fracturing

Non ideal pressure decline is observed during Non ideal pressure decline is observed during minifracminifrac in soft rock formationsin soft rock formations

57

ConclusionsIn offIn off--shore shore fracpacksfracpacks, temperature log can identify , temperature log can identify fracture heightfracture height

For thin, well confined reservoirs, HRWP attain better For thin, well confined reservoirs, HRWP attain better results than fracturing with gel results than fracturing with gel

Even for completely unconsolidated sands, stress Even for completely unconsolidated sands, stress anisotropy affects fracturing results anisotropy affects fracturing results Vertical (or Vertical (or verticalizedverticalized well) is betterwell) is better

Do not perforate the entire interval to obtain TSODo not perforate the entire interval to obtain TSO

Good practices result in lower skinsGood practices result in lower skins

58

MoreMore

59

Carlos Alberto [email protected]

Phone: 55 22 99862010

60

Back up & ComplementationBack up & Complementation

61

FRACPACK – Definition

Combination of the fracturing Combination of the fracturing with gravel packwith gravel pack

High permeability fracturing job High permeability fracturing job pumped with screens (GP pumped with screens (GP assembly) installedassembly) installed

62

FRACPACK – Basic concepts

Tip screen out (TSO)

Planned and controlled Screen Out at the Tip of the fracture, interrupting its propagation. The continuity of gel and proppant pumping causes the fracture width increase, which is proportional to the increment of the net pressure The TSO may happen with the arrival of the proppant at the tip of the fracture, demanding a very precise design.

63

Tip Screen Out

64

Tip Screen Out

Well Well –– Top viewTop view

65

Sand Control OptionsCased & Perforated Cased Hole Gravel

Pack Slotted Liner /

Screen in Open Hole

Open Hole Gravel Pack

Expandable Screen Cased Hole Frac Pack

After Darell Wood

66

Expandable ScreenCased & perforatedCased & perforated

O.L.O.L. Field VenezuelaField Venezuela

–– Cased & perforatedCased & perforated–– Heavy oilHeavy oil–– Swabbing for 4 hrs for Swabbing for 4 hrs for

testing testing sandingsanding–– Decided to remove Decided to remove

ExpadableExpadable ScreensScreens

–– Hot spotsHot spots

67

HotHot--SpotsSpots

Expandable Screen

68

Cased & PerforatedCased & PerforatedExpandable Screen

69

Partial ExpansionPartial Expansion

Expandable Screen

70

Expandable ScreenCased & perforatedCased & perforated

Conclusions from Service CompanyConclusions from Service Company

Fail occurred due to heavy oil flowing through Fail occurred due to heavy oil flowing through “restricted” perforations“restricted” perforations

Indication: Do not run expandable screens into cased Indication: Do not run expandable screens into cased producers wellsproducers wells

71

ExpandablesExpandables in in OffOff--ShoreShore Open Open HoleHole Horizontal Horizontal WellWell

250250250250250250150150250250250250150150

# (# (μμm)m)

PrPrPrPrPrPrPrPrInInInInInIn

TypeType

FailFailNonNon CompliantCompliant274274VV--11

FailFailCompliantCompliant620620MSMS--22

FailFailCompliantCompliant507507MSMS--11

2220022200CompliantCompliant390390MM--22

> 40000> 40000CompliantCompliant10081008MM--44



Q (Q (bbl/dbbl/d))ScreenScreenL (m)L (m)WellWell

72

Documents

Frac-pack in Ultra Deep Water