A speculative ridge within the Kidson Sub-basin – integrated interpretation from geophysical data

Abstract

This paper presents an analysis of the basement geometry and its implications on the Kidson Sub-basin in the southern Canning Basin. Integration of seismic data primarily near the rim of the sub-basin with airborne electromagnetic data across its central portion reveals an east-northeast oriented ridge at Permian level, suggesting a possible elevated structure in the Ordovician and basement. The proposed ridge effectively separates the Kidson Sub-basin into two distinct parts, providing an explanation for facies and thickness variations observed in the Nambeet and Goldwyer formations, as well as the absence of the Willara Formation in the southeastern portion of the sub-basin. The presence of shallowing trends observed in seismic profiles along the southern flank of the ridge suggests the proximity of the basement high. The ridge is speculative and requires further work to verify its existence, potentially including passive and reflection seismic surveys across the structure. If confirmed, it might be a significant feature with far-reaching implications for the prospectivity of resources in the Kidson Sub-basin. The hydrocarbon sourced from the Nambeet, Goldwyer and Bongabinni formations in the NNW depocentre may have migrated via the extension of the Parallel Range Fault and be trapped in the footwall block over the ridge. Compared to the structures in the Fitzroy Trough, the traps within the Kidson Sub-basin are expected to maintain reasonable integrity and have good potential for petroleum accumulation and carbon sequestration in the thick Paleozoic succession.