DarcyLog


Darcylog: measurement of permeability on drill cuttings


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 DarcyLog: Porosity and Permeability measurements from Drill Cuttings – DarcyLog Commercial Brochure


Domains of application

  • Dry and clean cuttings. Size: 1- 5 mm.
  • Permeability: 0.05 to 100 mDarcy.

Cuttings Requirements

  • Minimum volume of 3 cc after cleaning and sieving.
  • Porosity > 5%.

Principle

  • Air is trapped inside the cuttings during an imbibition in a viscous liquid.
  • Pressure is applied (10 bar) on the liquid to force it to enter into the cuttings and compress trapped air bubbles.
  • Permeability is derived from the transient pressure drop, similar to a well test.

Limitations

  • Darcylog is not a “push-button” apparatus. Interpretation of the relaxation curve requires experience and expertise, and can be difficult in case of mixture of formations during sampling.
  • Cuttings are not always representative of the reservoir: high permeability sandstone can be crushed into sand, and cuttings can sometime only represent shale layers.
  • Cuttings represent only the “matrix” permeability; fractures and vugs are lost during drilling.