The authors present the results of a detailed experimental study in which underlying pore-level-displacement physics of two- and three-phase flow in a fractured rock sample is investigated with high-resolution X-ray microtomography techniques. A unique, three-phase coreflooding setup integrated with a microcomputed-tomography (micro-CT) scanner is used to conduct flow experiments on a miniature, partially fractured sandstone sample to shed light on subtle displacement mechanisms governing matrix/fracture interactions in the presence or absence of spreading oil layers.
Rock and Fluid Properties. A water-wet Berea sandstone core plug, 38 mm in diameter and 100 mm in length, was subjected to continuous, nonuniform stress to create a fracture parallel to the stress axis. The artificial fracture was induced such that it ran through only half of the core plug. This configuration was used to study pore-fluid occupancies and displacement physics at different locations of the medium including matrix-only sites, the fracture, and the matrix adjacent to the fracture. After inducing the fracture, a miniature sample, 10 mm in diameter and 40 mm in length, was cut from the core plug.
The coreflooding tests were carried out with two different fluid systems representing the spreading and nonspreading conditions. X-ray dopants were added to liquid phases to establish sufficient contrasts among all phases (i.e., brine, oil, and gas) during the image-processing steps. All fluids were recirculated through the coreflooding setup before starting the experiment, bypassing the core sample at the experimental conditions for a period of time (i.e., 48 hours) sufficient to equilibrate all the phases and minimize mass transfer between the fluids in the core sample during the experiments....
Three-Phase Flow in Fractured Porous Media: Investigation of Matrix/Fracture Interactions
01 September 2017