Acoustic signatures of patchy saturation

We consider two saturation patterns in a partially saturated geomaterial[ The _rst is the homogeneous pattern where saturation is the same at the pore scale at any location in the rock[ The second is the patchy pattern where a large fully!saturated patch is surrounded by a dry region[ In both cases the global saturation in a large volume of the rock is the same[ At the same global saturation\ the e}ective acoustic properties of the rock vary depending on the saturation pattern[ We o}er a practical method for identifying the dominating saturation pattern from dynamic Poisson|s ratio obtained from sonic well!log measurements[ This method performs well in soft rocks whose acoustic properties are most sensitive to the way ~uid is distributed in the pore space[ 0887 Elsevier Science Ltd[ All rights reserved[