04/19/23 10.1-1

Borehole Integrity10.1-1

H arold V an ce D ep artm ent

P etro leu m E ngin eer ingTTAA MM

Serguei Jourine

Texas A&M University

1 April 2003

04/19/23 10.1-2

Outline

Deep Water Blowouts and Bridging Wellbore Bridging Model Bridging Scenarios Current Activity Conclusions

04/19/23 10.1-3

Deep Water Blowouts

FOR MORE INFO...

Flak L.: “Control of Well Issues”, “Marine Insurance – Facing the Changed World”, International Union of Marine Insurance-NEW YORK – 2002, on-line http://www.iumi-newyork -2002.org/Flak.htm

4 deepwater sustained underground blowouts controlled by Boots & Coots

3 broached mud line gas flows (20” casing set BOPs installed)

1 BOP Failure Gas Blowout

No oil blowout has reported to date

04/19/23 10.1-4

Deep Water BlowoutsProposed practical solutions:capping,

relief well drilling,

injecting solidified reactive fluids,

inducing bridging

04/19/23 10.1-5

Fastest and Least Expensive

FOR MORE INFO...

SPE 53974, IADC/SPE 19917, http://www.boots-coots-iwc.com /references/ 02_Ultra-deepwater %20blowouts.htm

39 %

911

95

19

53

Bridging BOP

Cement Depletion

Equipment Mud

Relief Well Missed

0-1 hour1 hour-1 day1-3 days3 days-1 week1 week- 1 month> 1 monthMissed

15%

36%14%

14%

10%4% 7%

Duration Mode of Control

04/19/23 10.1-6

Bridging Models

The known mechanisms that govern the bridging phenomenon are mostly qualitative

None of the available [simple] simulators can directly model the bridging processes

04/19/23 10.1-7

Outline

Deep Water Blowouts and Bridging Wellbore Bridging Model Bridging Scenarios Current Activity Conclusions

04/19/23 10.1-8

Model ConceptWellbore will bridge if ALL CONDITIONS exist: Unstable productive

formation and/or open hole; Total pressure drop exceed

formation pressure or stable bridge is formed within wellbore;

Formation is strong enough to prevent underground blowout.

UNSTABLE WELLBORE

UNSTABLE FLOW

STABLE BRIDGE

STRONG FORMATION

04/19/23 10.1-9

Model ConceptPressure Profiles

IPR

Wellbore stability

Outflow performance

Produced Solids

FEA & OUTFLOW

FALSEDYNAMIC BRIDGING

FEA

Bridge Stability

TRUESTATIC BRIDGING

Formation Stability

FEATRUE

FALSE

UNSTABLE WELLBORE

UNSTABLE FLOW

STABLE BRIDGE

STRONG FORMATION

C1

C2

C2

C2

04/19/23 10.1-10

Model: BackgroundInflow Performance: Jones equations for liquid, gas and gas condensate reservoirs; Fetkovich (Normalized back pressure) equation.

Outflow Performance:

1.Multiphase steady state liquid-gas flow analysis based on Beggs and Brill correlation and “3P” flow analyser algorithm (M.Hein);

2.Multiphase steady state solid-fluid flow analysis based on engineering correlations (G.Chase, M.Rhodes)

04/19/23 10.1-11

Model: BackgroundStress-Strength Analysis: Axisymmetrical linear elastic solution for heterogeneous formation (Finite Element Analysis)

Hydro-Mechanical Failure: Mass balance of the produced solids and flowing fluid (particle erosion and Darcy's law for fluid flow in porous media)

04/19/23 10.1-12

Outflow performance curve is totally above the reservoir performance curve

0

1000

2000

3000

4000

5000

0 50000 100000 150000

Pbh, psi

q, MscfD

300,000 lb/hr

200,000

100,000

0 0

5

10

15

20

25

30

35

40

0 50 100

Mean Stress, MPa

Dif

fere

nti

al S

tre

ss

, MP

a Stresses are less than

strength Mohr-Coulomb and

Drucker-Prager

C2C1Model: Criteria

04/19/23 10.1-13

Preliminary Model

Inflow Reservoir PerformanceModel

Outflow Wellbore PerformanceModel

Wellbore GeomechanicsModel

Subroutines and Implementation

04/19/23 10.1-14

Excel VBA Fortran 90 Excel-based unified

interface Independent

subroutines Default FEA meshes ASCII export format for

FEA visualization Low hardware

demands

Subroutines and Implementation

04/19/23 10.1-15

In-Situ Stresses

Data for Criterion 2 BC for FEA

1. Well DescriptionWater depth for offshore fields, ft 6637Depth of Sediments, ft 20700

2. Reservoir DescriptionFractional Porosity at the mud line 0.41Fluid (Water) Density in g/cc 1.074Matrix Density in g/cc 2.6Porosity Depth Model Value, K 8.71E-05 GOM

Pressure Profiles

0

5000

10000

15000

20000

25000

0 5000 10000 15000 20000

Pressure, psi

De

pth

, ft

Overburden

Hydrostatic

1

C20

5

10

15

20

25

30

35

40

0 50 100

Mean Stress, MPa

Diff

eren

tial S

tres

s, M

Pa

04/19/23 10.1-16

2

Gas IPR

0

2000

4000

6000

8000

10000

12000

14000

16000

0 5000000 10000000 15000000

Gas Rate, Mscf

Pre

sure

, ps

i

Data for Criterion 1

0

1000

2000

3000

4000

5000

0 50000 100000 150000

Pbh, psi

q, MscfDC1

IPR1. Well Description

Wellbore drainage radius, ft 1053Wellbore radius, ft 0.708

2. Reservoir DescriptionAverage reservoir pressure, psia 15000Reservoir permeability, md 104Reservoir thickness, ft 145Reservoir temperature, oR, 136

3. Oil ReservoirOil viscosity, cp 0.7Oil formation volume factor, bbl/STB 1.4Effective oil permeability, md 104Oil density, lbm/ft 58Flow coefficient (Fetkovich) 102.8Exponent (Fetkovich) 0.5Maximum production rate,StbD 1.75E+05

4. Gas ReservoirPermeability to gas, md 2000Gas compressibility factor 1Gas gravity (air=1) 0.6Gas viscosity, cp 0.012Maximum production rate, MscfD 1.02E+07

Run

04/19/23 10.1-17

1. Well DescriptionWellbore diameter,inch 16.99Overal Pipe Length, ft 14063Pipe Inclination Angle,rad 1.570796327Leakage Depth, ft 6637

2. Reservoir DescriptionReservoir temperature, oR, 150Fixed Outlet Pressure,psi 3086.319522Starting Reservoir Pressure (Inlet), psi 10000Maximum Gas production rate, MscfD 1.21E+07Maximum Oil production rate, 30Inlet Gas Flow rate,scfd 100Inlet water Flow Rate, stbd 1000GOR 0.00000001

3. Fluid PropertiesGas Gas gravity (air=1) 0.7

Molal %Nitrogen In Gas 0Molal % Carbon Dioxide in Gas 0Molal % Hydrogen Sulfide in Gas 0

Oil Oil Gravity API, degree 40Water Weight % of Salt in Liquid Water 0

4. Calculation ParametersSeparator Temperature, 0F 90Sparator Pressure,psi 14Number of Pipe Increment 50Pressure increment, psi 1000

3Outflow

04/19/23 10.1-18

Pressure Profiles

0

5000

10000

15000

20000

25000

0 5000 10000 15000 20000

Pressure, psiD

epth

, ft

Overburden

Hydrostatic

Fluid

3

Flow rate and pressure distribution along the blowing well Data for Criterion 2 BC for FEA

Gas IPR

0

2000

4000

6000

8000

10000

12000

14000

16000

0 2000000 4000000 6000000 8000000 10000000

12000000

Gas Rate, Mscf

Pres

ure,

psi

C2

0

5

10

15

20

25

30

35

40

0 50 100

Mean Stress, MPa

Diff

eren

tial S

tres

s, M

Pa

Outflow

04/19/23 10.1-19

FEA Subroutines Excel based interface Preprocessor with

default meshes Solver Simple postrocessor Export to common

powerful postprocessors

Visualization (Tecplot 9.0)

04/19/23 10.1-20

Finite Element Analysis (Preprocessor)

1. Structure and Element DataNumber of elements (Total) 3000Number of elements (R-Direction) 30 Max 30Number of elements (D-Direction) 100Number of nodes 3131Number of Integrating Points 9

2. Mesh and MaterialsYuong Modulus, psi

Poisson Ratio

Rock Density 0

3.Constrains and LoadsNode Freedom Data 31

Number of Loaded Nodes 185R-DirectionD-Direction

4. InformationFEA Files Paths

C:\0_Jourine\Research\Results_05\SingleFEA\P54.dat

5.Create Mesh

Depth of the Top,ft 0Vertical Load, % 58.28427Well Radius ,ft 1Horizontal Load, % 1.6Fluid Pressure, % 0

FEA

04/19/23 10.1-21

Outline

Deep Water Blowouts and Bridging Wellbore Bridging Model Bridging Scenarios Current Activity Conclusions

04/19/23 10.1-22

0

1000

2000

3000

4000

5000

0 50000 100000 150000Flow Rate

Pre

ss

ure

3

Massive Solid Production

4U

ns

tab

le

Mo

de

rate

S

tab

le

5

Total Wellbore Collapse

6

Negligible Solid Production

Stable Fluid-Solid Flow

Formation Failure

Blowout

7

Bri

dg

e

Stable Fluid Flow Underground Blowout

Bridge Failure

Wellbore BridgingGas Iinflow and Outflow PR

0

2000

4000

6000

8000

10000

12000

14000

16000

0 2000000 4000000 6000000 8000000 10000000

12000000Gas Rate, Mscf

Pre

sure

, ps

i

Pressure Profiles

0

5000

10000

15000

20000

25000

0 5000 10000 15000 20000

Pressure, psi

De

pth

, ft

Overburden

Hydrostatic

Fluid

1

2

Time, sec

Distance, m

Solid Load

Concentration

0

1000

2000

3000

4000

5000

0 50000 100000 150000Flow Rate

Pre

ss

ure

3

Massive Solid Production

4U

ns

tab

le

Mo

de

rate

S

tab

le

5

Total Wellbore Collapse

6

Negligible Solid Production

Stable Fluid-Solid Flow

Formation Failure

Blowout

7

Bri

dg

e

Stable Fluid Flow Underground Blowout

Bridge Failure

Wellbore BridgingGas Iinflow and Outflow PR

0

2000

4000

6000

8000

10000

12000

14000

16000

0 2000000 4000000 6000000 8000000 10000000

12000000Gas Rate, Mscf

Pre

sure

, ps

i

Pressure Profiles

0

5000

10000

15000

20000

25000

0 5000 10000 15000 20000

Pressure, psi

De

pth

, ft

Overburden

Hydrostatic

Fluid

1

2

Time, sec

Distance, m

Solid Load

Concentration

Bridging Scenarios

04/19/23 10.1-23

1. Well is out of Control

3

Gas Iinflow and Outflow PR

0

2000

4000

6000

8000

10000

12000

14000

16000

0 2000000 4000000 6000000 8000000 10000000

12000000Gas Rate, Mscf

Pre

sure

, p

si

Pressure Profiles

0

5000

10000

15000

20000

25000

0 5000 10000 15000 20000

Pressure, psi

Dep

th, f

t

Overburden

Hydrostatic

Fluid

1

2

1. Wellbore and Reservoir Performance Relationships2. Stress and Pressure Distributions

3. Stress-Strength Relationships

Flow and Geomechanics Models

04/19/23 10.1-24

2. Wellbore Instability

3. Stress-Strength Relationships4. Solid Production Potential

Wellbore Stability Model

4U

nst

able

M

od

erat

e S

t ab

l e

3

04/19/23 10.1-25

Stable Fluid Flow

3. Solid Production

4. Solid Production Potential

5. Actual Solid Production

Solid Production Model

5

Blowout

Time, sec

Distance, m

Concentration

4Massive Solid Production

Negligible Solid Production

04/19/23 10.1-26

4a. Wellbore Collapse

5. Actual Solid Production

6. Outflow Performance with Actual Solid Load

Flow and Geomechanics Models

5

Massive Solid Production

Negligible Solid Production

0

1000

2000

3000

4000

5000

0 50000 100000 150000Flow Rate

Pre

ss

ure

Total Wellbore Collapse

6

Wellbore

Bridging

04/19/23 10.1-27

4b. Bridge Formation

6. Outflow Performance with Actual Solid Load7. Bridge and Formation Stability

Flow and Geomechanics Models

0

1000

2000

3000

4000

5000

0 50000 100000 150000Flow Rate

Pre

ss

ure

6

Stable Fluid-Solid Flow

7B

r id

ge

Blowout

04/19/23 10.1-28

5. Bridge Stability

7. Bridge and Formation Stability

Flow and Geomechanics Models

7

Bri

dg

e

Blowout

Formation Failure

Underground

Blowout

Bridge Failure

Wellbore

Bridging

04/19/23 10.1-29

Deep Water Tendency

0

1000

2000

3000

4000

5000

0 50000 100000 150000Flow Rate

Pre

ss

ure

3

Massive Solid Production

4U

ns

tab

le

Mo

de

rate

S

tab

le

5

Total Wellbore Collapse

6

Negligible Solid Production

Stable Fluid-Solid Flow

Formation Failure

Blowout

7

Bri

dg

e

Stable Fluid Flow Underground Blowout

Bridge Failure

Wellbore BridgingGas Iinflow and Outflow PR

0

2000

4000

6000

8000

10000

12000

14000

16000

0 2000000 4000000 6000000 8000000 10000000

12000000Gas Rate, Mscf

Pre

sure

, ps

i

Pressure Profiles

0

5000

10000

15000

20000

25000

0 5000 10000 15000 20000

Pressure, psi

De

pth

, ft

Overburden

Hydrostatic

Fluid

1

2

Time, sec

Distance, m

Solid Load

Concentration

0

1000

2000

3000

4000

5000

0 50000 100000 150000Flow Rate

Pre

ss

ure

3

Massive Solid Production

4U

ns

tab

le

Mo

de

rate

S

tab

le

5

Total Wellbore Collapse

6

Negligible Solid Production

Stable Fluid-Solid Flow

Formation Failure

Blowout

7

Bri

dg

e

Stable Fluid Flow Underground Blowout

Bridge Failure

Wellbore BridgingGas Iinflow and Outflow PR

0

2000

4000

6000

8000

10000

12000

14000

16000

0 2000000 4000000 6000000 8000000 10000000

12000000Gas Rate, Mscf

Pre

sure

, ps

i

Pressure Profiles

0

5000

10000

15000

20000

25000

0 5000 10000 15000 20000

Pressure, psi

De

pth

, ft

Overburden

Hydrostatic

Fluid

1

2

Time, sec

Distance, m

Solid Load

Concentration

04/19/23 10.1-30

Outline

Deep Water Blowouts and Bridging Wellbore Bridging Model Bridging Scenarios Current Activity Conclusions

04/19/23 10.1-31

Numerical Procedure

Subroutines Debugging Default FEA Meshes:

- clean wellbore;

- bridged wellbore;

- wellbore bottom.

04/19/23 10.1-32

Rock Properties

Center for Tectonophysics, TAMU

In Progress

04/19/23 10.1-33

Conclusions Model and numerical procedure calculate the flow

properties for a produced solid-fluid mixture and estimate the stress distribution within the borehole under blowout conditions.

Preliminary results of computer simulations provide insight into the predominant factors that control bridging in deep water environment.

The model explains wellbore bridging at early time, possible restarting of fluid flow and increased probability of underground crossflow in bridged well

04/19/23 10.1-34

Conclusions Current activity:

- numerical procedures and code debugging;

- default meshes development for most probable scenarios;

Real data are still critical for model validation

04/19/23 10.1-35

Conclusions The investigation is the part of project "Development of

a Blowout Intervention Method and Dynamic Kill Simulator for Blowouts Occurring in Ultra-Deepwater" conducted under Dr. J.J. Schubert and Dr. P.P. Valko supervision.