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Drilling Technology Studies in Kakkonda Geothermal Reservoir

Learn how drilling technology was evaluated in drilling a 4000m deep geothermal well in Kakkonda, Japan, to combat high-temperature formations using innovative methods and overcoming challenges of gas ejection.

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Drilling Technology Studies in Kakkonda Geothermal Reservoir

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  1. How did we drill 500 oC formation in Kakkonda JAPAN March 17, 2002 IDDP workshop Iceland

  2. MajorProject Elements • FUNDS: Japanese Government (NEDO) • Duration: 1992-2000, WD-1 drilling 1994-97 • Main purpose: To delineate deep geothermal reservoir Drilling technology studies • To evaluate drilling technology (2) To obtain useful data for practical use • Planned Well Depth: 4000m • Expected F.Temp: 400℃

  3. 1994 1995 1996 1997 1998 km Side Track １ 9-5/8” Tie-back Stuck pipe ２ Set 7” Slot -P Prod. Test ３ Set Scab Liner & Corro. Test CSG Retrieve test CSG ４ 3.729m Drilling History of WD-1

  4. PDM MWD-tool Bit O-ring seal Mud dispersant 150-175 (oC) 150-175 140-170 ? 250 (weighted) 300 (unweighted) Temp. Limitationsfor drill tools & materials

  5. MWD PDM Stator Rubber PDM Can’t be used above 150 oC

  6. O-ring Seal Three-cone bit life decrease drastically above 150 oC operating Temp.

  7. Borehole temp. changes with different operations Highest Temp. Cond. MTO MTI POOH DRG RIH

  8. Mud Temp. In Pump Rate RIH speed Borehole Temp. TDS-Cooling Method 50oC 130 ?? 200oC ??

  9. TDS(Top-drive Drilling System) Conventional Usages ・Work efficiency (can drill 27m, instead of 9m continuously) ・Prevent stuck pipe New Usage ・Cool BHA while RIH Water swivel Motor

  10. Borehole Dynamic Survey Experiments Temperature Memory Tools

  11. Trajectory correction with PDM & MWD 8-1/2 inch 2600m FT:350oC

  12. Evaluation of the TDS-Cooling Method Bit Life Comparison With & without TDS-Cooling method

  13. Economic Evaluation of the TDS-Cooling Method

  14. How did we combat with HT-Formation ? • Get as manyTemp. info. as possible • Mud cooling system • TDS-cooling method • Re-injection well • Enough Water • Well organized group(both Drlg. & Sci.) • Perseverance

  15. Mud-Cooling System Geo-Cooler Conventional Mud Cooler Pit

  16. Drill Mud Deterioration

  17. Mud DeteriorationWhat has happened • When well depth was 3451m (and below): • When we circulated mud at 2546m CSG shoe, 2100ppm CO2 gas came up. • At 3000m • 17300ppm CO2 gas • Flow-back at 10 l/min mud • While drilling • High CO2 gas mud returned

  18. CO2 gas content vs Depth Well Depth (m)

  19. Mud-Additives, S-contents & CO2 Gas Ejection Temp.

  20. CO2 Source Survey (Fresh Mud Pumping Test) Fresh-Mud

  21. Countermeasures • Quit using Polymer • Add Lime • Spot fresh water before POOH BHA Results: CO2 gas contents decreased from 10kppm to 2kppm

  22. H2S Gas Ejection H2S gas content mud (>100ppm) returned when mud was circulated at 3,642m But H2S content decreased after 30 min circulation

  23. Countermeasure • Closed re-injection system

  24. Well Depth: 3729m

  25. Terminated Deepening the Well BECAUSE • Incapable of increasing mud density (High Temperature) • Risk of more gas ejection when encountered lost circulation zone

  26. Drilling Research Items in Kakkonda Evaluation of １．TDS-cooling method ２．Casing damage & CMT-bond (USI-Log) ３．MDW & PDM ４．Three-cone bit bearing (O-ring seal) • Multiple-stage-cementing method • Mud additives in HT-condition 7. Cooling effects by Mud-coolers 8. CSG Corro.Monitor while producingbrine

  27. 13-3/8”CSG

  28. Casing Corrosion Test Scab-liner

  29. The End

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