PESA QLD June Luncheon

Geological structures and aquifer connectivity in the Great Artesian Basin and underlying Permian-Triassic basins: insights from airborne electromagnetic surveys, hydrochemistry and environmental tracers at Narrabri, NSW

Presented by: Dr Matthias Raiber

(Principal Research Scientist at CSIRO)

Abstract:

In the Narrabri region, understanding connectivity between coal seam gas (CSG) reservoirs and overlying aquifers is important for assessing potential groundwater impacts and addressing community concerns, given that the Gunnedah Basin, which hosts the coal seams, underlies key Great Artesian Basin (GAB) units such as the Pilliga Sandstone.

This study applies an integrated workflow combining airborne electromagnetics (SkyTEM), seismic interpretation, K/Ar dating of igneous intrusions, and hydrochemical and environmental tracer datasets (including noble gases and groundwater age tracers). The SkyTEM survey (~2,765 line km; >60 flight lines) provides high-resolution constraints on subsurface architecture, enabling mapping of faults, intrusions, and key stratigraphic boundaries to ~400 m depth.

AEM results and K/Ar ages of intrusive activity were integrated with seismic and geological data to develop conceptual hydrogeological models identifying potential connectivity pathways. Hydrochemical and tracer data were then used to test for evidence of hydraulic connection across formations and basins, allowing structural interpretations to be evaluated against groundwater signatures.

Results indicate that geological structures are widespread, but their hydraulic significance and therefore their potential influence on connectivity varies across the study area.

The presentation focuses on the Narrabri Gas Project area while also addressing broader GAB connectivity questions. The integrated workflow provides a transferable framework for reducing uncertainty in subsurface fluid flow, with relevance to hydrocarbon studies, hydrogen storage, Carbon Capture and Storage (CCS), and related applications.

Event Details:

Date: Thursday, June 25th 2026

Luncheon: 12 pm for a 12:30 pm start

Place: Stamford Plaza Brisbane

Bookings close 5 pm Tuesday, June 23rd 2026 unless sold out prior.