Deepwater Cementing

Deepwater Cementing

What Makes Deepwater Different?  Riserless drilling of top hole section  Modeling and prediction of downhole temperatures  Narrow margin between pore pressure and fracture gradients  Beyond the conductor – Type of drilling fluids – Drilling fluid rheology – Tight clearances due to many casing – Casing damage due to trapped fluid pressure  General differences – Cost of deepwater drilling rigs – More planning required 2 © 2011 HALLIBURTON. ALL RIGHTS RESERVED.

Deepwater Riserless Cementing  Low seabed temperatures  Narrow margin between pore pressure and fracture gradients  Shallow Water Flow (SWF) potential  Gas hydrates  Poor displacement mechanics

 What about ultra-deepwater? – Further cooling effects – Tighter fracture & pore pressure windows – Increased trip times can increase mud gels 3 © 2011 HALLIBURTON. ALL RIGHTS RESERVED.

Deepwater Riserless Solutions – BHCT & BHST  Low temperature – – – –

API temps not suitable WellCat modelling for slurry placement temps Consider effects of Heat of Hydration (HoH) Optimise TT & CS to minimise WOC • Cement designs for low temps Undisturbed Model (BHST) MWD Measured Temperature Gradient Prediction (API) Model Prediction

4 © 2011 HALLIBURTON. ALL RIGHTS RESERVED.

Deepwater Riserless Solutions – BHCT & BHST  Summary of Temperature Study – MWD / LWD BHCT’s frequently indicate BHCT well above the simulated BHCT throughout the well. – Predictions based on API tables are significantly higher than simulated BHCT throughout the well. • Over-predictions can affect the amount of retarder and/or other additives required for a slurry. • This can effect the set time of the cement based on the use of additional additives and retarders. • Incorrect temperature assumptions can ultimately increase non-productive time.

Deepwater Riserless Solutions – Slurry Design  Tight fracture & pore pressure window – Low density slurries with low viscosity • Tuned Light / Foam Cement / EconoCem  Shallow Water Flow – Cement with rapid transition time • GasStop / FlowStop  Gas Hydrates – No documented cases of problems cementing across formations containing hydrates • If risk is considered high, use cement design with low Heat of Hydration

6 © 2011 HALLIBURTON. ALL RIGHTS RESERVED.

Deepwater Riserless Solutions – Mud Removal  Poor Displacement Mechanics – Mud removal should be analysed with iCemSM Service – If poor mud removal is a risk consider ChannelSeal II • Settable Spotting Fluid (SSF) placed in the hole prior to running casing • Will set up faster when exposed to cement’s HoH

7 © 2011 HALLIBURTON. ALL RIGHTS RESERVED.

Managing The Interface  Displacement Mechanics – Gel strength measurements – Aqueous and non-aqueous fluids • Compatibility and wettability – Erodibility models – Rheological hierarchy

Non-Gelling Drilling Fluid A

Severely Gelling Drilling Fluid B

Specific Lab Testing for Non-Aqueous Fluids  Apparent Wettability Apparatus and methodology have been developed by Halliburton to provide the following: – a simple, repeatable test that can be carried out in any properly equipped cementing-service laboratory – the study of emulsion behavior of spacer and mud mixtures at any temperature up to 190°F – a method for customizing surfactant blends on an individual job basis for maximum performance and minimum material volumes – customization of phase inversion point for improved compatibility

SBM containing a Water Phase and an Oleaginous Phase Oil Phase

Water Phase Phase Inversion

Water Phase

Oil Phase

Emulsifiers Oil External Emulsion

Apparent Wettability Apparatus

Water External Emulsion

Annular Fluid Expansion  Fluid Trapped in the annulus at low temperature will expand when exposed to the higher temperatures encountered while producing the well.  This pressure increase can be large enough to cause severe casing damage  Effective solutions: – Leave cement short of previous casing – Cement the entire annulus – Controlled leak path or bleed port – Compressible foamed fluids – Syntactic crushable foam wrap – Heavyweight casing design

Annular Pressure Buildup

Potential Pressure Increase on Trapped Annulus due to Temperature Increase 12000 Tap Water

10000

10.3 CaCl2 10.3 CaCl2 & Foamed Spacer

PSI

8000 6000 4000 2000 0 40

60

80

100

120

Temperature

140

160

180

Foam Quality Vs. Pressure

Conclusions / Summary  #1 time saver in deepwater: – Do it right the first time! • Proper planning • Proper execution • Follow best practices and industry standards • Document lessons learned  One squeeze job to remediate a poor primary cement job in deepwater can cost > $1,000,000

16 © 2011 HALLIBURTON. ALL RIGHTS RESERVED.

Case Histories / Best Practices  “Deepwater Cementing Case History Using a HighStrength Lightweight Blend” – DOT Conference  “Deepwater Cementing Best Practices for Riserless Section” – AADE-05-NTCE-70  “Deepwater Cementing Challenges” – SPE 56534  “Determination of Temperatures for Cementing in Wells Drilled in Deep Water” – IADC/SPE 39315  “Saving Expensive Offshore Deepwater Rig Time by Modeling Accurate Subsea/Subsea-Floor Temperature Modeling for Cementing Operations” – SPE 123738  “The Importance of Hydration Heat on Cement Strength Development for Deep Water Wells” – SPE 62894  “Improved Deepwater Cementing Practices Help Reduce Nonproductive Time” – IADC/SPE 99141 17 © 2011 HALLIBURTON. ALL RIGHTS RESERVED.

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