Preparation of the saturating water for sample GB13
Water chemically equilibrated with sample GB13 was prepared and injected as follows: For several weeks before saturation, we submerged a few grams of GB13 granules in deionized water. Then, the injection of such aqueous fluid was performed using a high-pressure syringe pump (ISCO 260HP), recording – via a Matlab script - the injected volume and injection pressure. The latter was maintained constant to a value of 3 MPa lower than the confining pressure that varied between 20 and 50 MPa.