Geochemical analyses

Exploring for the Future is an Australian Government program, led by Geoscience Australia, dedicated to exploring Australia’s resource potential and boosting investment. A key component of this program is improving the understanding of the petroleum prospectivity of the South Nicholson Basin in northern Australia.

A 1750 m drill hole, NDI Carrara 1, was drilled in 2020 as part of the MinEx CRC National Drilling Initiative at a location near the Northern Territory/Queensland border, approximately 250km north-west of Mount Isa. Initial results indicate the drill hole intersected rocks of the Georgina Basin, possibly the South Nicholson Basin, and terminated in the Paleoproterozoic Isa Superbasin package. The drill hole was designed to help geologists understand the relationship between the Beetaloo Sub-basin, McArthur Basin and Georgina Basin with the underexplored South Nicholson Basin and Lawn Hill Platform. In order to assist with basin-to-basin correlations, Geoscience Australia proposes to carry out detailed high-end geochemical analyses on source rocks and oil stains of the Georgina Basin. These data will be able to be compared to those that will be acquired on Cambrian rocks in NDI Carrara 1.

Deliverables

The Supplier will carry out biomarker analyses on samples from wells of the Georgina Basin.

The analytical services will include:

• Sample preparation where necessary

• Sample solvent extraction on 36 rocks to obtain an organic extract

• Programmed pyrolysis on 36 rocks in order to get Total Organic Carbon (TOC), S1, S2, S3 and Tmax.

• Sample fractionation by liquid chromatography to obtain saturated and aromatic hydrocarbon fractions on 20 organic extracts

• High-resolution gas-chromatography (HRGC) on 36 organic extracts from rocks in order to obtain main linear alkanes, isoprenoids and C7 hydrocarbons concentrations and ratios (including, but not limited to, Thompson, Mango and Halpern ratios).

• Biomarker analyses by Gas-Chromatography coupled to Mass Spectrometry (GC-MS) using selected ion mode (SIM) monitoring the following ions with mass charge ratio (m/z):

• 177, 191, 205, 217, 218, 221, 231 and 259 (on 24 saturated hydrocarbon fractions) in order to obtain most common steranes and terpanes data;

• 133, 156, 170, 178, 184, 188, 192, 198, 231, 239, 245, and 253 (on 24 aromatic hydrocarbon fractions) in order to obtain most commonly used alkylaromatics and aromatic steroids data.

• High-end biomarker analyses on 36 organic extracts from rocks using as gas-chromatography coupled with tandem mass spectrometry (GC-MS-MS) with precursor/product ion transitions monitoring terpane/hopane/sterane biomarkers, diamondoids, carotenoids, alkylaromatics and aromatic steroids.

• Bulk carbon isotopic measurements on 20 saturated and 20 aromatic hydrocarbon fractions.

• Provision of concentration of biomarker data in ppm and of most commonly used biomarker ratios (cf. Biomarker Guide) as Excel spreadsheets.

• Provision of pictures of full chromatograms from HRGC and most common ion chromatograms and precursor/product ion transitions traces (e.g., provided as powerpoint or PDF files).

• Provision of instrument raw files.