Geophysical monitoring data of the hydro-mechanical-chemical evolution of a synthetic sandstone with carbonate clasts exposed to CO2 during 6-month at reservoir stress conditions

This dataset stores geophysical, transport and chemical data collected during a six-month experiment involving CO2-brine-rock interaction with stress, at reservoir conditions. The rock used for the tests was manufactured in the National Oceanography Centre, Southampton, following the procedure described in Falcon-Suarez et al. (2019). The aim was to study the coupled hydro-mechanical-chemical (HMC) phenomena that occurred in sandstone reservoirs containing carbonates, when interacting with CO2 during Carbon Capture and Storage (CCS) operations. The dataset includes results from two brine-CO2 flow-through tests and three intercalated hydromechanical assessments, where elastic (P- and S-wave velocities and attenuations), transport (bulk electrical resistivity and permeability) and axial strain data were collected and analysed together with basic petrophysical properties. Results from a reactive simulation developed using free-software PHREEQC (Parkhurst and Appelo, 2013) are also included. The tests were conducted in the high-pressure, room-temperature (20 C) experimental setup for multi-flow-through tests in the Rock Physics Laboratory at the National Oceanography Centre, Southampton (NOCS), from 2021 to 2025, as part of the projects GASRIP, EHMPRES and FOCUS (NERC grants NE/X003248/1 - FAPESP-EHMPRES, NE/X006271/1 - FOCUS and NE/R013535/1 - GASRIP). References Falcon-Suarez, I.H., Amalokwu, K., Delgado-Martin, J., Callow, B., Robert, K., North, L., Sahoo, S.K., Best, A.I., 2019. Comparison of stress-dependent geophysical, hydraulic and mechanical properties of synthetic and natural sandstones for reservoir characterization and monitoring studies. Geophysical Prospecting 67, 784-803, https://doi.org/10.1111/1365-2478.12699. Parkhurst, D., Appelo, C.A.J., 2013. Description of input and examples for PHREEQC version 3: A computer program for speciation, batch-reaction, one-dimensional transport, and inverse geochemical calculations, Techniques and Methods, Reston, VA, p. 519. https://pubs.usgs.gov/publication/tm6A43 The spreadsheet file includes six sheets with contain information about (Info) the parameters and acronyms used in the file; (Sample_properties) the rock and fluid properties, including petrophysical properties and fluid composition; (BCFT-1 and BCFT-2) the data collected during the brine-CO2 flow-through tests; (HMA tests) the data collected during the hydromechanical assessments before and after BCFT-1, and after BCFT-2; and (Reactive model) the input and outputs from the reactive model performed using PHREEQC.