Measurements and Modeling of Multiphase Flow & Scaling Behavior in Tight Materials

K. E. Gray, J. Holder

Test facilities at the Center for Earth Sciences and Engineering have been engineered to experimentally determine multiphase flow behavior in very tight materials, for which few measurements are currently available. The systems provide for simultaneous flow of a liquid with gas, and, with minor modification, a second liquid, for steady-state determinations of multi-phase fluid flow behavior. Several different testing systems are available for measurements in 3/8^Prime, 1^Prime, 2^Prime, and 4^Prime to 10^Prime diameter cylindrical specimens, and in nominal 2^prime cubic or 2^prime diameter cylindrical specimens. Flow headers in the large specimen chamber provide for a wide range of flow configurations, including cross-flow, and for scale-model tests of borehole and reserv ir performance. All test systems have provisions for applications of confining and differential axial stresses, and the large chamber provides for application of true polyaxial stresses, during simultaneous flow. The laboratory measurement capabilities and integrated model simulations provide for direct assessments of scale-up laws and extrapolations to field conditions. Some of the systems provide for simultaneous measurement of p- and s-wave velocities and electrical resistivity during flow.

In an investigation of two-phase flow in shale, gas permeabilities were measured with steady-state flow in specimens partially saturated with water (brine). For flow along bedding, gas permeability (1.6 microdarcy at 7 kpsi) was determined within minutes, and a systematic permeability decrease was measured during triaxial deformation. For flow perpendicular to bedding, gas permeability (approximately 1 nanodarcy at 7 kpsi) measurements required on the order of a day each. Permeability after triaxial deformation decreased. Substantial decreases in permeability were observed in both specimens with effective pressure, between 100 psi and 7 kpsi. The permeability decreases with effective pressure and with triaxial deformations in both specimens were largely irreversible.

AAPG Search and Discovery Article #91020©1995 AAPG Annual Convention, Houston, Texas, May 5-8, 1995