Full text loading...
-
Heating Induced Shale Barriers
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, Sixth EAGE Shale Workshop, Apr 2019, Volume 2019, p.1 - 4
Abstract
In this work, it was investigated if heating of a cased borehole in a shale formation can induce plastic deformations that are sufficiently high to close the annulus between shale and casing and form a hydraulic barrier. This is of interest for plug and abandonment (P&A) of wells. Both laboratory experiments and numerical simulations have been carried out. Borehole heating experiments were performed with hollow-cylinder shale samples, using a novel experimental setup that allows for temperature and pore pressures measurements at different radial positions inside the shale samples. The results show that borehole heating results in a relatively large increase of pore pressure in the shale, inducing rock failure and annulus closure under certain temperature and stress conditions. A finite-element model was used for simulating the experimental data and obtaining relevant thermo-poro-elasto-plastic parameters. Those parameters were used in field-scale finite-element models to assess the possibility of forming shale barriers by borehole heating. The numerical models provide a good description of the experimental data; they indicate that under certain conditions heat induced displacement at the borehole wall is large enough to close the annulus around a casing.