LABORATORY METHOD FOR INVESTIGATING PERMEABILITY UPSCALING

The purpose of this work is to describe, evaluate, and demonstrate a l aboratory-based method for physically investigating permeability upsca ling. The method makes use of a simple instrument, the gas permeameter , to acquire rapid, precise, and nondestructive permeability measureme nts from heterogeneous blocks of dry rock. Critical to investigating p ermeability upscaling is the ability to acquire data at multiple sampl e supports subject to consistent boundary conditions and flow geometry . Such measurements, spanning almost 4 orders of magnitude on a per vo lume basis, are made with the gas permeameter by simply varying the si ze of the permeameter tip seal. The precision and consistency of measu rements made in this way were evaluated using a suite of data collecte d from blocks of three relatively homogeneous materials: Berea Sandsto ne and two synthetic rocks. Results suggest that measurement error is small (approximately +/-1% of the measured permeability) and consisten t, and measurements made at different sample supports are free from sy stematic bias. To demonstrate the ability of this method to measure an d quantify upscaling processes, limited data sets were collected with four different-sized tip seals from the Berea Sandstone block. Analysi s reveals distinct and consistent trends diagnostic of permeability up scaling relating the sample mean (increased), variance (decreased), an d semivariogram to increasing sample support.