Differentiating domains for CO2 sequestration at Harvey-3 via integration of geochemistry, spectral mineralogy, facies modelling and wavelet tessellation analysis

[摘要] Carbon capture and storage (CCS) refers to CO2 capture from industrial sources and long-term storage, to combat emissions, involving subsurface injection in supercritical state. Deep saline aquifers, including the South West Hub Project, Western Australia, present the greatest storage potential but there is only a small global portfolio of active investigations into CO2 geological storage. An ability to efficiently domain sediments, which are potential injection targets/barriers, is critical for predicting CO2 plume behaviour, e.g. potential fluid paths, and sediments’ storage ability, e.g. potential to baffle or provide conduits for fluid flow. Integrating lithofacies models with wavelet tessellation analysis (pseudo-logging) and interpreted mineralogy, using HyLogger hyperspectral data, has not previously been trialled. This study shows the ability to correlate sedimentary units, hyperspectral/geochemical data (Mineralyzer XRF scanning) and pseudo-logs to assess the Harvey Ridge’s CO2 sequestration suitability (South West Hub). An updated lithofacies model (eight lithofacies) has been produced due to lithological variation between the DMP Harvey-3 (1360–1460 m) and GSWA Harvey-1. These strata host a) the Wonnerup Member which represents fluvial palaeo-processes, dominated by very coarse, cross-bedded sandstones, and b) the Yalgorup Member which represents floodplain deposits and occasional swamps recurrently overlain by proximal–distal crevasse splays. The Brahmaputra River is a modern analogue. It is interpreted the Wonnerup Member sediments are sufficiently coarse/porous to be an ideal CO2 reservoir and the Yalgorup Member has high potential to baffle vertical fluid migration with low permeabilities and tortuous potential fluid paths due to high frequency sand/palaeosol alternations. Pseudo-logging XRF/gamma data has efficiently confirmed and located boundaries in target reservoir/seal sedimentary units. The Spectral Geologist hyperspectral data processing enables rapid mineralogical domaining and correlation with pseudo-logs. This trial is a template for domaining on other CCS projects and a reference for further lithofacies modelling and pseudo-logging of the Harvey wells, which is recommended.

[发布机构] CSIRO

[学科分类] 地球科学(综合)