Integration of HyLogging data with geochemical, well log and biostratigraphic data in the Georgina Basin, Queensland and Northern Territory, Australia

Geoscience Australia is currently assessing selected Australian sedimentary basins for their unconventional hydrocarbon resource potential, in collaboration with the Northern Territory and state governments. A study of the southern Georgina Basin is in progress, involving the compilation of a cross-border dataset of all accessible open file seismic, well, geological and geochemical data that will be publicly released in mid-2014. Major geochemical resampling of old wells has generated new information on source rock characteristics, kerogen kinetics, and gas and oil isotope geochemistry in the Georgina Basin. Preliminary 3D geology and 1D petroleum systems models have also been generated. Several cores from the Georgina Basin have been HyLogged by the geological surveys of Northern Territory, Queensland and New South Wales, using HyLogging facilities funded by AuScope Pty Ltd and CSIRO as part of the National Collaborative Research Infrastructure Strategy (NCRIS) and AuScope National Virtual Core Library (NVCL) Project. Geoscience Australia currently has a project underway to reprocess the raw HyLogging data using a common set of mineral scalars, to create an internally-consistent, basin-wide dataset. An initial composite HyLogging data package was publicly released in March 2014, including reprocessed data for 14 wells in the southern Georgina Basin, information about the processing methods used, and metadata. A second stage of the project will involve interpretation of the reprocessed data from these wells, to further examine the relationships between the spectroscopic and mineralogical properties measured by the HyLogger, and core total organic carbon (TOC), XRD, XRF and ICPMS compositional data, well log data, and biostratigraphic data. Initial work has indicated interesting trends, such as the apparent relationship between gamma intensity, core SWIR albedo (mean shortwave infrared reflectance) and quartz content. Peaks in gamma intensity broadly align with troughs in albedo, suggesting that the reduced albedo is a result of increased TOC content. However, in others cores (or even the same core), peaks in gamma intensity also appear to correlate with potassium-rich phases such as white micas and other clay minerals, thus the gamma correlation does not appear straightforward. Other preliminary observations indicate that using HyLogging data provides (i) the opportunity to review the existing formation picks in the basin from a mineralogical perspective, (ii) new information on variations in calcite/dolomite proportions in the carbonate sequences, (iii) the ability to map apatite distribution, and (iv) mineralogical evidence of sedimentary cyclicity. It is thus hoped that integrated interpretation of the HyLogging data and other data types will enable clearer delineation of the lower Arthur Creek Formation (and the 'Hot Shale' within) in the Georgina Basin, and therefore assist in constraining target intervals for future unconventional hydrocarbon resource assessments.