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Ises 2013 day 2 - malin torsæter (arctic researcher, sintef) - arctic drilling


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  • 1. Technology for a better society International Student Energy Summit (ISES),  June 14th 2013 Malin Torsæter, PhD Research Scientist Dept. of Drilling and Wells SINTEF Petroleum Research Preparing for Safe  Arctic Well construction 1 Photo: Stockbyte/Getty Images
  • 2. Technology for a better society Preparations for crossing the "final frontier" 2
  • 3. Technology for a better society Varying: • Ice conditions (sea, subsurface) • Temperature (air, seafloor) • Ocean currents Everywhere: • Darkness, remoteness, sensitive area • Short operational windows • Unknown geology, ground in motion • Poor wellbore position accuracy • Cold "tophole" of well and stronger temperature cycling (on/off production) Not "one Arctic" ‐ Different well solutions are required for different Arctic locations 3 J. Bang and T. Torkildsen (2011), "Wellbore Anti‐ Collision Safety: Separation Distances Must Be  Increased Due To Degraded Positioning Accuracy  In Northern Areas", SPE 149699. Source: AAPG Arctic ice cap Onshore & offshore permafrost
  • 4. Technology for a better society Summary: Challenges of Arctic wells 4 Freezing/thawing of formations Barrier isolation/  lifetime challenges More wax/  hydrate formation Freezing of water‐ based fluids Cold top section of well Less possibilities for shipping  fluids/equipment from shore Same season well control?  Less time for drilling Short operational time windows More robust well construction needed, less time for repairs Minimal emissions Drill cutting & water  disposal? Well abandonment  procedures? Operations that minimize CO2 em.? New monitoring technologies?
  • 5. Technology for a better society 5
  • 6. Technology for a better society Extra slides to be brought up if necessary during discussion 6
  • 7. Technology for a better society The life of a hydrocarbon well Well integrity: "Application of technical, operational  and organizational solutions to reduce  risk of uncontrolled release of formation  fluids throughout the life cycle of a well." NORSOK D‐010 Standard 7 Drilling • Drill string & bit • Mud (closed loop) • Cuttings Source: Chief Council's Report Casing &  completion • "Save" progress • Stabilize wellbore  • Make ready for  production Source:Chief Council's Report • Cut casing and set  cement plugs. • Zonal isolation for  eternity. Abandonment Source: Indian Oil&Gas Canada Production • Controlled flow  of hydrocarbons • Remediation  Source: Indian Oil&Gas Canada
  • 8. Technology for a better society 8 15 year old well in GoM: 50% probability to leak United States Mineral Management Service (MMS) survey on sustained casing pressure (SCP) of 15500 wells in the Gulf of Mexico. Brufatto et al. (2003), "From Mud to Cement ‐ Building Gas Wells", Oilfield Review.
  • 9. Technology for a better society 38% of temporarily abandoned wells on NCS have issues 9 2 defect barriers 1 defect barrier 1 reduced barrier No WI issues PSA, SINTEF & Wellbarrier study of 193 temporarily abandoned wells O. K. Helgesen (2011), "Stor fare for lekkasje fra forlatte oljebrønner", Teknisk Ukeblad, 3. Oct.
  • 10. Technology for a better society #1: Wells are often not properly  designed/operated • Ex: Gas‐Lift wells – SINTEF study on NCS – Average time for WI problems after  conversion to gas‐lift: 2 years. Average life of gas  lift wells Wells operated outside their design envelope: 10 • Understand critical design factors: – Casing depth selection – Length of annular cement sheath – Centralizer placement – Designing wells with plans for P&A
  • 11. Technology for a better society 11 Gap along casing‐ cement interface Cement porosity Degraded casing Cracks in  cement Gap along cement‐ formation interface Based on: Celia et al., Quantitative Estimation of CO2 Leakage from Geological Storage, ICGGCT (2004) #2: Placement and integrity  of well barriers
  • 12. Technology for a better society There are several ways to define "the Arctic" 12
  • 13. Technology for a better society Arctic drilling is not a new topic 13 First "Arctic wave" Source: Wood Mackenzie • 1970s & 1980s: 176 wells (85 offshore) were drilled only in the Canadian Arctic. • There is a strong relation between the oil prize and drilling activity in the Arctic • We seem to be seeing the start of a second "Arctic wave"
  • 14. Technology for a better society Challenges escalate with water depth 14 Source: Imperial Oil (Canada)
  • 15. Technology for a better society Source: animal.discovery.comSource: Photo: The Arctic environment Sensitive nature/ wildlifeRemote locations Challenging subsurface conditionsHarsh topside conditions Photo: UNODA Cold "tophole" 15 Source: Howstuffworks Source: Close to north pole
  • 16. Technology for a better society Harsh topside conditions • Short operational windows • Speed up operations • Less frequent repairs • On/off production • Need to protect top section of the well • Iceberg scours down to 400 m water depth 16 Photo: C. Teff (Royal Dutch Shell), "Mud Line Cellar Construction for Arctic Wells", Alaska Exploration (2009).
  • 17. Technology for a better society 17 Challenging subsurface conditions Permafrost G. Cherkashov, "Russian studies on subsea permafrost and gas  hydrates in the Arctic", VNIIOkeangeologia, St. Petersburg Gas hydrates Source: AAPG ? ?
  • 18. Technology for a better society Why avoid thawing  of frozen soil? Xie et al. (2011), "Methodology to Assess Thaw Subsidence Impacts on the Design and Integrity of Oil and Gas Wells in Arctic Regions", SPE 149740. 18 Ca. 20 m radial thaw after 10 years of production • Up to 9% volume reduction • Can lead to:  – (local) subsidence that imposes severe  loads on casing and wellhead/BOP. – Caving that compromises zonal isolation
  • 19. Technology for a better society Why avoid thawing of  gas hydrates? 19 • Trapped gas molecules (often methane)  in a solid framework of water molecules – Under permafrost – Beneath sea in outer continental margins • During thawing, trapped gas is released* – Pressure build‐up – Mud gasification – Poor cement jobs • Reported consequences** – Catastrophic subsidence – Uncontrolled gas release – Collapsed casings ** Yakushev et al. (1992), "Gas hydrates in Arctic regions: risk to drilling and production", Int. Offshore and Polar Eng. Conf. 1:669‐673 *Tan et al. (2005), "Mechanical and Petrophysical Characterisation and Wellbore  Stability Management in Gas Hydrate‐Bearing Sediments", ARMA/USRMS 05‐833 Image: NOC Photo: softpedia
  • 20. Technology for a better society Cold "tophole" 20 (2) Boyer and Szakolczai (2011), "Well Architecture and Well Operating Procedures on Kharyaga Field, Russia", OTC 22133 Suppression of temperature gradient down to  600 m at Kharyaga Field(2) (1) Punase et al. (2011), "Soybean slurry – a new effective, economical and environmental friendly solution for oil congealing", SPE 142658 (3) Singh et al. (2007), "An application of vacuum‐insulated tubing for wax control in an Arctic environment", SPE 111006  Functioning of BOP/safety valves(1‐3) – Plugging/freezing A typical  wax plug(3) Gas hydrate plug  (SINTEF)  Frequent flow assurance issues(1‐3) – Freezing of produced water – Wax forming – Gas hydrates forming  Difficulties during on/off operations – Freezing of water based well fluids • Suppression of normal temperature gradient in Arctic wells
  • 21. Technology for a better society What does cold "top hole" mean? 21 IKU News 1988: Målinger av temperatur i grunne brønner sør for Svalbard Beaufort Sea  = Worst case? South of Svalbard  = Best case? Xie et al. (2011), "Methodology to Assess Thaw Subsidence Impacts on the Design and Integrity of Oil and Gas Wells in Arctic Regions", SPE 149740.
  • 22. Technology for a better society Cold well barrier materials 22 *Reinås et al. (2011), "Hindered Strength Development in Oil Well Cement due to Low Curing Temperature", SPE 149687. **Limaye et al. (2011), "Contamination Resistante Phosphate Ceramic Cement for Arctic Applications", Int.Offshore and Polar Eng. Conference. • New environment = new predicted lifetime • Cement in the Arctic: • Freezing of water before setting • Enhanced permeability • Poor bonding to formation • Lower compressive strength* • Proposed solution: new sealant types** • Steels in the Arctic: – Brittle at low temperatures – Stress‐based design – Proposed solution:  other materials*** ***M. Y. Gelfgat et al. (2009), "Aluminium pipes – a Viable Solution to Boost Drilling and Completion Technolgy", IPTC 13758. Surface casing failure, Alaska  (Anders et al. (2008), "Prudhoe  Bay Well P2‐15 Surface Casing  Failure", SPE 116771) Cement and steel are  weakest where the  loads are largest!
  • 23. Technology for a better society Wellbore Position Accuracy J. Bang and T. Torkildsen (2011), "Wellbore Anti‐ Collision Safety: Separation Distances Must Be  Increased Due To Degraded Positioning Accuracy  In Northern Areas", SPE 149699. • Wellbore trajectory defined by depth, inclination  and azimuth. • Magnetic instruments: azimuth uncertainty dep. on  horizontal component of geomagnetic field.  • Gyroscopic instruments:  azimuth uncertainty dep. on  horizontal component of the  earth rotation. • Important for: – well collision avoidance – safety margins with respect  to e.g. faults – Planning/drilling relief wells – required size of a target
  • 24. Technology for a better society • Drilling muds are chosen with respect to  e.g. weight and hole cleaning properties. • Their effect on the sealing ability of cement was recently investigated by SINTEF. Ex. Choices made during drilling  affect long‐term well integrity 24 Interface porosity: sandstone Interface porosity: shale No mud WBM OBM No mud WBM OBM N. Opedal et al. (2013), "Leakage of CO2 along cement‐formation interfaces in wellbores", Energy Procedia.
  • 25. Technology for a better society 25