WA Branch talk: Geomechanical and petrophysical properties of rock salt for energy/gas storage

WA Branch's upcoming event where Mustafa Sari will talk on Geomechanical and petrophysical properties of rock salt for energy/gas storage.

Title: Geomechanical and petrophysical properties of rock salt for energy/gas storage

Presenter: Mustafa Sari, CSIRO Energy

Registration: https://www.eventbrite.com.au/e/aseg-wa-branch-event-sept-2022-tech-night-tickets-401605391537

Date: 29/09/22

Time: 1730 - 2000 AWST

Location: The Shoe Bar and Cafe, 376 - 420 Wellington Street, Perth, WA 6050

About this event:

We evaluate of the suitability of the Frome Rocks salt dome for waste disposal or energy storage in deep boreholes, i.e., depth > 600m in the Canning basin, Western Australia(McNee et al., 2021). This evaluation involves the characterization and testing of the petrophysical, mineralogical, microstructural and geomechanical properties of rock salt samples from two contrasting facies in this formation: a shallower (800m) heterogeneous facies with 40% halite and 38% of dolomite inclusions (mm to cm in size, see figure); and a deeper (1100m) homogeneous, halite-rich facies. The petrophysical testing involves porosity, and gas permeability estimation as a function of effective confining pressure; and the geomechanical testing involves multi-stage triaxial testing at four distinct effective confining pressures (see figure), one of which corresponds to the estimated in-situ effective pressure prevailing at the depth of recovery of each sample (purple curves, see figure). The other stages simulate possible stress perturbation associated with drilling/excavation operations in the native formation.

During each stage of the multi-stage triaxial test, additional gas permeability tests are conducted under hydrostatic and deviatoric stress conditions; and creep tests are conducted under deviatoric stress corresponding to 75% of the yield stress at that depth. The laboratory data show that the homogeneous (heterogeneous) salt facies exhibit a porosity in the range 0.8-1.1% (0.2-0.3%), and a gas permeability in the range 50-500 mD (1-20 mD) in the confining pressure interval 0-16 MPa. Subsequent triaxial testing of the samples lasted about 80 days for each facies sample, essentially due to the time-consuming nature of the multiple gas permeability and creep tests conducted during each test.