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Air Drilling Tight Gas Reservoirs

D
dzwager

The document discusses air drilling of tight gas reservoirs. It describes how air drilling keeps pressures and water influxes low to avoid issues. Key equipment for air drilling includes compressors, mist pumps, and special air hammer bits. Case studies are presented of successful air drilling projects in the San Juan Basin of New Mexico and the Mereenie and Palm Valley fields in Australia. Air drilling provides benefits like reducing formation damage, increasing penetration rates, and improving well productivity and recovery rates.

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Air Drilling Tight Gas Reservoirs Diederik Zwager & Frank Seidel
Air Drilling Gas Reservoirs How we get away with it #1: keep the pressures low No restrictions at the surface #2: no liquid hydrocarbons If present, switch to membrane N2 #3: preferably no water influxes Can be handled by misting, foam
Air Drilling Equipment Primary air compressors Booster Mist Pump Rotating head (Grant, Washington, Williams) Float valves Fire float/stop
Blooie Line & Flare Flow line jet (venturi) Igniter
Percussion Air Hammers (Cubex, Drill-Quip, Ingersoll-Rand, Numa, ...) With air/mist, sometimes foam Typical max dP only 250 psi Require low weight on bit, controls deviation Special carbide insert bits Wide variety of sizes WATER CHECK VALVE WEAR SLEEVE INTERNAL CYLINDER PISTON PIN DRIVE SPLINE SYSTEM BIT
San Juan Basin, New Mexico San Juan Basin, New Mexico, USA Cretaceous, Sandstone Reservoirs 75 years of commercial gas production 7% of US gas production 30,000+ wells drilled 1,700 2,200 m measured depth 250 3,000 psi BHP 0.01-0.1 md rock quality
San Juan Basin Drilling Mud drill intermediate hole Casing set through producing water intervals Air/Nitrogen drill production hole Tight pay zones flow little gas Drilled with Air Hammers and Bits : up to 50 m/hr
Mereenie & Palm Valley Amadeus Basin, NT Pacoota sandstone Extremely hard (50kpsi compressive strength) Mud rop: 1 m/hr
Mereenie & Palm Valley Amadeus Basin, NT Air Drilling No water influxes Used air hammers 15 20 m/hr Palm Valley Usual 10-15 mmscfd Extremes of 69 & 136 mmscfd encountered Mereenie Up to 30 mmscfd/well Very abrasive Significant wear on rotating head Ceramic liners considered Drill oversize holes, allow bit to wear
Bit Trips & Completions Bit trips & completion Strip live well through rotating head Run retrievable packer, use snubbing unit to run completion
Air Drilling Tight Gas Reservoirs Keeps swelling shales dry No lost circulation, no formation damage, in sub-normal pressured zones Provides increased penetration rate, no chip hold down Provides less hole deviation, less weight on bit required
Contact Energy Ltd New Zealand Reductions in Formation Damage (Fewer) Cuttings material in fractures Enhanced Well productivity Olkaria 3 5 MWe/well drilled conventially 8 12 MWe/well drilled with air Mokai 5 10 MWe/well drilled conventially 8 20 MWe/well drilled with air Rotokawa 5 10 MWe/well drilled conventially 10 30 MWe/well drilled with air Putauaki 5 8 MWe/well drilled conventially 12 20 MWe/well drilled with air Ohaaki 2 6 MWe/well drilled conventially 8 15 MWe/well drilled with air Reduced thermal recovery period
Reykjavik Energy, HS Energy Iceland Fractured volcanic World record 12-1/4 tri-cone bit runs 1,472 m @ up to 30 m/hr (May 21-26, 2006)

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Air Drilling Tight Gas Reservoirs

  • 1. Air Drilling Tight Gas Reservoirs Diederik Zwager & Frank Seidel
  • 2. Air Drilling Gas Reservoirs How we get away with it #1: keep the pressures low No restrictions at the surface #2: no liquid hydrocarbons If present, switch to membrane N2 #3: preferably no water influxes Can be handled by misting, foam
  • 3. Air Drilling Equipment Primary air compressors Booster Mist Pump Rotating head (Grant, Washington, Williams) Float valves Fire float/stop
  • 4. Blooie Line & Flare Flow line jet (venturi) Igniter
  • 5. Percussion Air Hammers (Cubex, Drill-Quip, Ingersoll-Rand, Numa, ...) With air/mist, sometimes foam Typical max dP only 250 psi Require low weight on bit, controls deviation Special carbide insert bits Wide variety of sizes WATER CHECK VALVE WEAR SLEEVE INTERNAL CYLINDER PISTON PIN DRIVE SPLINE SYSTEM BIT
  • 6. San Juan Basin, New Mexico San Juan Basin, New Mexico, USA Cretaceous, Sandstone Reservoirs 75 years of commercial gas production 7% of US gas production 30,000+ wells drilled 1,700 2,200 m measured depth 250 3,000 psi BHP 0.01-0.1 md rock quality
  • 7. San Juan Basin Drilling Mud drill intermediate hole Casing set through producing water intervals Air/Nitrogen drill production hole Tight pay zones flow little gas Drilled with Air Hammers and Bits : up to 50 m/hr
  • 8. Mereenie & Palm Valley Amadeus Basin, NT Pacoota sandstone Extremely hard (50kpsi compressive strength) Mud rop: 1 m/hr
  • 9. Mereenie & Palm Valley Amadeus Basin, NT Air Drilling No water influxes Used air hammers 15 20 m/hr Palm Valley Usual 10-15 mmscfd Extremes of 69 & 136 mmscfd encountered Mereenie Up to 30 mmscfd/well Very abrasive Significant wear on rotating head Ceramic liners considered Drill oversize holes, allow bit to wear
  • 10. Bit Trips & Completions Bit trips & completion Strip live well through rotating head Run retrievable packer, use snubbing unit to run completion
  • 11. Air Drilling Tight Gas Reservoirs Keeps swelling shales dry No lost circulation, no formation damage, in sub-normal pressured zones Provides increased penetration rate, no chip hold down Provides less hole deviation, less weight on bit required
  • 12. Contact Energy Ltd New Zealand Reductions in Formation Damage (Fewer) Cuttings material in fractures Enhanced Well productivity Olkaria 3 5 MWe/well drilled conventially 8 12 MWe/well drilled with air Mokai 5 10 MWe/well drilled conventially 8 20 MWe/well drilled with air Rotokawa 5 10 MWe/well drilled conventially 10 30 MWe/well drilled with air Putauaki 5 8 MWe/well drilled conventially 12 20 MWe/well drilled with air Ohaaki 2 6 MWe/well drilled conventially 8 15 MWe/well drilled with air Reduced thermal recovery period
  • 13. Reykjavik Energy, HS Energy Iceland Fractured volcanic World record 12-1/4 tri-cone bit runs 1,472 m @ up to 30 m/hr (May 21-26, 2006)