Polymer-based injectates delivered by microcapsules are being evaluated as a means to modify fracture permeability to limit preferential flow that can lead to thermal short-circuiting. The microcapsules are sized so they enter only the larger, problematic fractures and rupture at elevated temperatures anticipated in the reservoir to deliver the polymer at the desired location. We report on experiments to understand microcapsule transport and determine the fracture size below which microcapsules are excluded from entry, i.e., the blocking function, for a rough fracture. Flow visualization experiments were conducted to study the flow of microcapsules using water as the carrier fluid in transparent, horizontal rough fractures. The fracture characteristics (aperture, connectivity) was varied by both normal and shear displacement. A camera was used to record movement of the particles in the fractures. Microcapsule passage through, retention in, and exclusion from the fracture were measured. Image analysis methods were used to track microcapsule movement and interpret the amount of fracture blocking that occurs as a function of fracture characteristics and microcapsule size.

Press the Back button in your browser, or search again.

Copyright 2023, Stanford Geothermal Program: Readers who download papers from this site should honor the copyright of the original authors and may not copy or distribute the work further without the permission of the original publisher.