Trapped Annular Pressure: Trapped Annular Pressure: A Spacer Fluid that Shrinks (Update)A Spacer Fluid that Shrinks (Update)Ron Bland, Ron Foley, Floyd Harvey, Baker Hughes Drilling Ron Bland, Ron Foley, Floyd Harvey, Baker Hughes Drilling Fluids, Ben Bloys, Many Gonzales, Chevron, Robert Hermes, Fluids, Ben Bloys, Many Gonzales, Chevron, Robert Hermes, Los Alamos National Laboratory, John M. Daniel, Floyd Los Alamos National Laboratory, John M. Daniel, Floyd Billings, Ian Robinson, Lucite International, Marlon Allison, Billings, Ian Robinson, Lucite International, Marlon Allison, Flow Process Technologies, John Davis, Terry Cassel, Baker Flow Process Technologies, John Davis, Terry Cassel, Baker Oil ToolsOil Tools

What is Trapped Annular Pressure? What is Trapped Annular Pressure? (or Annular Pressure Buildup)(or Annular Pressure Buildup)

•When cement is not circulated back to surface, drilling fluids or spacers become trapped in the annulus between the top of cement and the wellhead

•Heat from produced oil/gas /water causes thermal expansion of these trapped annular fluids and can create more than enough pressure to collapse casing and tubing strings

From SPE 89775 - Pattillo, et al

What is Trapped Annular Pressure?What is Trapped Annular Pressure?

• Mostly an issue in subsea completed wells

• Previous mitigation techniques include VIT, heavy walled casing, nitrogen-based spacers, burst disks, crushable foam, leaving cement short of shoe, etc.

A New ApproachA New Approach

•• Cooperative research between Chevron and Los Alamos Cooperative research between Chevron and Los Alamos National Lab led to the development of a shrinking National Lab led to the development of a shrinking spacer based on spacer based on methyl methacrylate (MMA)methyl methacrylate (MMA)

•• MMA is a liquid monomer that polymerizes to form many MMA is a liquid monomer that polymerizes to form many familiar items like plastic windows and acrylic familiar items like plastic windows and acrylic paperweights, and is the active ingredient in many latex paperweights, and is the active ingredient in many latex paintspaints

•• MMA MMA shrinks 20%shrinks 20% as it changes from emulsified liquid as it changes from emulsified liquid MMA droplets to tiny solid polyMMA droplets to tiny solid poly--MMA particlesMMA particles

Trapped Annular Pressure Trapped Annular Pressure Shrinking Spacer (TAPSS) FormulationShrinking Spacer (TAPSS) Formulation

MMA is emulsified into a standard waterMMA is emulsified into a standard water--based spacer at based spacer at 1010––50%50%

•Water•Biopolymer (for viscosity)•Barite (1st test – 12 ppg)•Emulsifiers•MMA (1st test - 28%)•Defoamer•Inhibitor •Initiator (added as spacer is pumped) •Bicarb & caustic•Dispersant

TAPSS Preparation OverviewTAPSS Preparation Overview

Water-Based Mud

MMA Monomer

Metering Mixer

MMA/WBM EmulsionTransportedto Wellsite

Metering Mixer

InitiatorSolution

PumpDownhole

MidMid--Scale Field TrialScale Field Trial

Test site in Bossier City, Test site in Bossier City, LA had a 500LA had a 500--ft, cased wellft, cased wellBuilt an annulus from 7Built an annulus from 7””and 9and 9--5/85/8”” casing, with 3casing, with 3--1/21/2”” pipe within for hot pipe within for hot water injectionwater injectionPressure testedPressure tested

Test ResultsTest ResultsTrapped Annular Pressure Mitigation

TAPSS vs. Standard Spacer

0

500

1000

1500

2000

2500

3000

3500

4000

4500

0 20 40 60 80 100 120 140 160 180

Minutes of Annulus Heating

Ann

ulus

Pre

ssur

e -p

si

TAPSS

Standard Spacer

Polymerization begins

TAPSS After ReactionTAPSS After Reaction

Thicker, but still liquid with 28% Poly-MMA

Compatibility with Drilling OperationsCompatibility with Drilling Operations

Elastomers Elastomers OKOK BunaBuna®® (butadiene nitrile)(butadiene nitrile)OKOK VitonViton®® (fluoroelastomer) (fluoroelastomer) OKOK UrethanesUrethanes

Contamination with Cement Contamination with Cement –– OKOK

Contamination with KCl, NaCl or CaClContamination with KCl, NaCl or CaCl22 –– OKOK

Contamination with SBM Contamination with SBM –– OK OK

Contamination with standard cement spacer Contamination with standard cement spacer -- OKOK

OffOff––Shore ProcedureShore Procedure

• Shipped to rig in closed-top, vented tanks

• Tank(s) spotted on rig (watch wt. limits)

• Mixed with initiator solution just before goingdown hole (initiator is a 5-7% feed)

• Pumped down hole using cement unit, or similar

• Should not mix with mud system, but 15% contamination in SBM only moderately reduces LC50

Safety IssuesSafety Issues

Detailed risk analysis/mitigation processDetailed risk analysis/mitigation processPure MMA has a low flash point Pure MMA has a low flash point -- 5555ºº F, similar to F, similar to methanol methanol -- only handled in mud plantonly handled in mud plantThe emulsified spacer has an open cup flash point of The emulsified spacer has an open cup flash point of 175175ºº FFFumes can accumulate in tank head space and Fumes can accumulate in tank head space and become a risk (grounding)become a risk (grounding)Plan to use the pumping unit to flush water back Plan to use the pumping unit to flush water back through lines and pump skid to original tankthrough lines and pump skid to original tank

Safety Issues, cont.Safety Issues, cont.

Tank bottoms, wash water, etc. will be treated Tank bottoms, wash water, etc. will be treated with a with a ‘‘hothot’’ initiator to eliminate any unreacted initiator to eliminate any unreacted MMAMMAProper PPE will be specifiedProper PPE will be specifiedDrips pans under all connectionsDrips pans under all connectionsAbsorbents for small spillsAbsorbents for small spillsSurfactants make the LCSurfactants make the LC5050 low, as expected low, as expected –– so so no offshore disposalno offshore disposal

Detailed Operations & Safety PlansDetailed Operations & Safety Plans

Land Test Land Test –– Carthage, TXCarthage, TX

A quick land trial was held in a A quick land trial was held in a tubing annulus to provide a full tubing annulus to provide a full scale test of:scale test of:–– Safety protocolsSafety protocols–– All mixing/metering equipment All mixing/metering equipment

and manifoldsand manifolds–– Pumping, and cleanPumping, and clean--up up

proceduresprocedures–– Initiator behaviorInitiator behavior

Spacer Mixing SkidSpacer Mixing Skid

Meter in Meter in MMAMMAEmulsify in a Emulsify in a single passsingle passPump to Pump to transport transport tanktank

MMA in

Mud in

Spacer to Tank

High ShearMixer

ManifoldManifold

Initiator Addition Skid (rig)Initiator Addition Skid (rig)

Meter in Meter in initiator initiator solutionsolutionMix well Mix well with spacerwith spacerCharge Charge main main pumping pumping unitunit Initiator in

Mud in

Mixer

Out to pump unit & well

Initiator Tank and Addition SkidInitiator Tank and Addition Skid

Wellhead Pressure vs. TimeWellhead Pressure vs. Time

0

200

400

600

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1200

0 10 20 30 40 50 60

Time (minutes)

Pres

sure

(psi

g) a

t man

ifold

Polymerization vs. DepthPolymerization vs. Depth

0

20

40

60

80

100

120

0 1000 2000 3000 4000 5000 6000 7000 8000

Vertical Depth (feet)

% c

onve

rsio

n of

m

onom

er to

pol

ymer

CleanClean--Up Flushing EffectiveUp Flushing Effective

ResultsResultsAll fluids accurately mixed and well emulsifiedAll fluids accurately mixed and well emulsifiedSmooth displacement into wellSmooth displacement into wellPressured to 1000 psiPressured to 1000 psiShrinkage occurred as expected (sampled Shrinkage occurred as expected (sampled during well cleanout):during well cleanout):–– Bottom of well (240Bottom of well (240°° F) F) –– hotter than St. Malo hotter than St. Malo

production temperature production temperature –– reacted quicklyreacted quickly–– Top of well Top of well –– similar temperature to St. Malo similar temperature to St. Malo

annulus annulus –– virtually no reactionvirtually no reactionAll equipment cleaned by flushing with rinse All equipment cleaned by flushing with rinse water back to original tankwater back to original tankNo HSE incidentsNo HSE incidents

Preparing for a Deepwater TrialPreparing for a Deepwater Trial

Genesis

Tahiti

Gemini

Petronius

BlindFaith

Great White

Trident

CVX producing properties - GOMBU

Discoveries – CVX Op

Exploration Wells

Tubular Bells

Silvertip/Tobago

Cat. Deep

Discoveries – Non Op

Knotty Head

Tiger

St MaloJack

Puma

Projects – CVX Op

Tonga

Projects – Non Op

Big Foot

Appraisal Projects

Tahiti #710¾” tieback annulusQ2’09

DiscovererDeep Seas

Planning a TAPSS Application: Planning a TAPSS Application: Determine the extent of the problemDetermine the extent of the problem

1.1. Model temperatures and pressures in trapped Model temperatures and pressures in trapped annulusannulus–– During seal formationDuring seal formation–– Maximum during flow testing/productionMaximum during flow testing/production–– Geothermal and hydrostaticGeothermal and hydrostatic

2.2. Compare the above with casing and seal Compare the above with casing and seal assembly ratings to determine the assembly ratings to determine the minimumminimum pressure reduction needed during flow pressure reduction needed during flow testing/production to stay within casing/seal testing/production to stay within casing/seal assembly ratingsassembly ratings

Planning a TAPSS Application: Planning a TAPSS Application: IsIs TAPSS a feasible solution?TAPSS a feasible solution?

3.3. Calculate fluid volume shrinkage needed at Calculate fluid volume shrinkage needed at maximum flow test temperatures/pressures to maximum flow test temperatures/pressures to achieve pressure reduction in achieve pressure reduction in ‘‘2.2.’’ aboveabove

4.4. Using new fluid volume and pressures from Using new fluid volume and pressures from ‘‘3.3.’’ above, calculate shutabove, calculate shut--in pressures under in pressures under geothermal conditionsgeothermal conditions

5.5. Are shutAre shut--in pressures using new fluid volume in pressures using new fluid volume within casing/seal assembly ratings?within casing/seal assembly ratings?

6.6. If no, TAPSS may not be a feasible solution for If no, TAPSS may not be a feasible solution for well design/flow test schedulewell design/flow test schedule

Tieback Example with 16Tieback Example with 16”” LinerLiner

Well: Subsea Completion #1 Rig: BA Drillship #1Mudline Location: WBS No.

API Well Number:BHL Location: Latitude/Longitude.:

RT to MSL (ft): ±90'OBJECTIVES: Water Depth (ft): ±7000DIRECTIONAL: RT to ML (ft): ±7000'

18-3/4" HPWH @ -16' 16' AML38" Housing @ -12' 12' AML

EVAL GEOLOGIC MARKERS HOLE CASING MUD LOTPROG OBJECTIVES MD TVD SIZE & CEMENT MW OBG/FG

±7400'

MWD/LWD t/ TD ±300' 36" Jetted to ±300' BML ±300'

TVD±8800' ±8800'

' 500' Tail, TOC @ Mud-line, 200% OHE10 3/4" X 9-7/8" CROSSOVER @ +/- 9,500'

TVD 13-5/8" TOL @ < 17K'17,000'MD 16"to ±17000'

16" LS @ ±7,400

Example Deepwater Casing Diagram

Drilling Schematic

Straight Hole

MDBML

TOS @ 8,509'8,509' BML

26" Hole

MDBML

±17000

22" to ±8800'

Planning a TAPSS Application: Planning a TAPSS Application: Determine extent of pressure relief possibleDetermine extent of pressure relief possible

7.7. If yes, TAPSS may be a feasible solution and If yes, TAPSS may be a feasible solution and additional pressure relief may be possible additional pressure relief may be possible –– Try increasing pressure reduction in Try increasing pressure reduction in ‘‘AA’’ aboveabove–– Recalculate fluid volume shrinkage requiredRecalculate fluid volume shrinkage required–– Recalculate shutRecalculate shut--in pressures under geothermal in pressures under geothermal

conditions using new volumeconditions using new volume–– Compare with casing/seal assembly design Compare with casing/seal assembly design

ratings ratings –– Continue iterations until casing/seal assembly Continue iterations until casing/seal assembly

design ratings are reacheddesign ratings are reached

Planning a TAPSS Application: Planning a TAPSS Application: Determine Fluid DetailsDetermine Fluid Details

8.8. Calculate trapped annulus volume capacityCalculate trapped annulus volume capacity9.9. Adjust for other fluids planned for annulusAdjust for other fluids planned for annulus10.10. Difference is maximum TAPSS volume possibleDifference is maximum TAPSS volume possible11.11. What is the desired TAPSS density as pumped What is the desired TAPSS density as pumped

downhole?downhole?12.12. Calculate TAPSS density as shipped allowing Calculate TAPSS density as shipped allowing

for initiator dilutionfor initiator dilution13.13. Determine maximum tank loading based on Determine maximum tank loading based on

empty tank weight, TAPSS density & rig deck empty tank weight, TAPSS density & rig deck load limitload limit

14.14. Calculate number of tanks neededCalculate number of tanks needed

Planning a TAPSS Application: Planning a TAPSS Application: What are rig constraints?What are rig constraints?

15.15. Choose TAPSS staging area based on:Choose TAPSS staging area based on:–– SpaceSpace–– Utility accessUtility access–– Deck load limitDeck load limit–– EvacuationEvacuation–– Cement pump if pump is on top deckCement pump if pump is on top deck

16.16. If cement pump on a lower deck a small HP If cement pump on a lower deck a small HP pump will probably be needed such as a gravel pump will probably be needed such as a gravel pack pumppack pump

Thanks to:Thanks to:

Management of Chevron, Los Alamos Management of Chevron, Los Alamos National Laboratory, Baker Hughes Drilling National Laboratory, Baker Hughes Drilling Fluids, Baker Oil Tools, Flow Process Fluids, Baker Oil Tools, Flow Process Technology and Lucite International for Technology and Lucite International for permission to present this work.permission to present this work.IADC and the Programme Committee for IADC and the Programme Committee for accepting our abstractaccepting our abstract

Questions?Questions?

Happiness is No Annular Pressure