Porosity and Permeability from Drill Cuttings

The early determination of rock petrophysical properties is one of the main concerns during the reservoir characterization process because it impacts directly the reserves (porosity, saturation) and also the well deliverability (permeability). Logs generally provide a good estimate of porosity and saturations along the well, but permeability is more difficult to obtain especially in carbonates. Drill cuttings can provide additional information on the petrophysical properties of the reservoir. In this paper, we have described a method for measuring permeability on drill cuttings with the following capabilities: size of cuttings down to 1 mm diameter,volume of cuttings around 1 cm3 (2-3 grams of dry cuttings),permeability from the microDarcy to around 100 mDarcy. The main constrain of the method is to need consolidated cuttings with a porosity larger than 4% in order to have a minimum volume of air trapped during the spontaneous imbibition. Porosity is difficult to measure on small cuttings. The more accurate method is based on NMR relaxometry with an apparatus dedicated to the measurement of small volumes.