Laboratory Testing to Study Initiation and Evolution of Shale Barriers

Abstract

Clay and shale formations occur naturally with sealing properties, and are therefore investigated as possible annular barriers. The properties of these argillaceous rocks are not fully understood with regards to creep of clay and shale. The aim of this thesis was to do experiments on a Pierre shale in order to observe if creep at elevated temperatures could attribute to create a natural annular barrier. The study mainly focused on the dilation process of argillaceous rocks and thermal effects. The clay-stones are highly dependent of their hydraulic conductivity, permeability, failure strength, swelling properties, thermal expansion etc. Two tests were conducted to assess the sealing properties of a Pierre shale. An attempt was made to find out how thermal effects and water content affected the clay behaviour, and in which magnitude. The thermo-hydro-mechanical behaviour of the clays proved to be important since it affects the rock during its lifespan, and it was observed that the pore water plays a central role in the deformation process of clays.