The use of geologic expression workflows for basin scale reconnaissance: A case study from the Exmouth Subbasin, North Carnarvon Basin, northwestern Australia

Abstract

The focus of this study is to demonstrate how seismic attributes can be used in the interpretation workflow to rapidly obtain a high-resolution view of the geology that is imaged within a seismic data set. To demonstrate the efficacy of seismic attribute analysis to basin scale reconnaissance, we apply a workflow to seismic data sets from the Exmouth Subbasin, northwestern Australia, with the aim of determining the geologic expression of the subsurface. Of specific interest are Barrow Group Jurassic and Cretaceous fluvial and marine sediments, that were faulted during the Jurassic-Cretaceous rifting associated with the breakup of East Gondwana. Regional-scale interpretations are made to develop a tectonostratigraphic context to the investigation. Target-level analyses, focused on features of exploration interest identified using regional reconnaissance, are made to calibrate attribute response and demonstrate the effectiveness of seismic attributes for rapid evaluation of prospectivity in the initial stages of exploration. The main structural episodes are distinguished using dip and azimuth attributes, and faulting is expressed using a combination of edge attributes which are used to create fault trend lineations. We observe three main structural trends: the main northeast–southwest Jurassic-Cretaceous syn-rift primary fault orientation of 48°, a secondary trend of 108°, taken to represent secondary conjugate faulting and a third trend of 100° interpreted as the reactivation of these faults into the postrift sediments. Stratigraphic attributes that respond to amplitude and frequency are used to create reservoir scale geobodies of faulted Macedon turbidites, which in turn are used for detailed tuning sensitivity analysis. The final part of the investigation is of the syn-rift magmatic system responsible for sills and dikes that exploit the normal fault network. These intrusive and extrusive features are important as are potential drilling hazards and can act as baffles to hydrocarbon migration.

Seismic expression and geomorphology of igneous bodies: A Taranaki Basin, New Zealand, case study

“…A solid black line is drawn to highlight these unknown facies. Based on the geomorphology and structural relation to the volcanic cone, we interpret the orange facies to be lava flows/volcanic tongues, such as those reported by Klarner et al (2006) and McArdle et al (2014). In terms of the spatial distribution in which pyroclastic and lava flows extend: One possible explanation to why the purple facies (pyroclastic flows) are more prominent in the eastern flank of the volcano and the orange (lava flows) facies dominate the western flank, may be related to the paleo-water currents flowing in the direction of the shoreline and evidenced by the ADC facies in the east (Figure 12; which appears to have been east-southeast, like today's Taranaki Peninsula shoreline), whereas the lava flows where dense enough to fight the water resistance and deposits mainly in the western flank.…”

“…Planke et al (2005), Klarner et al (2006), Jackson et al (2013), Alves et al (2015), and Delpino and Bermudez (2009) as well as others find that igneous sills often appear to be of high amplitude and bowl shaped, climbing upward to form a stacked but offset pattern. Klarner et al (2006), Pena et al (2009), and Zhang and Marfurt (2011) all map the characteristic volcanic cones seen on the earth's surface, although the associated volcanic flows and tuff appear similar to mass-transport complexes and other sedimentary features, such as lava flows that mimic distributary channels mapped by McArdle et al (2014). We have not seen any clear images of feeder stocks on data that we have analyzed from Mexico, China, or New Zealand, with the chaotic column of amplitude beneath a volcanic cone being overprinted by velocity pull-up and degraded imaging on time-migrated data volumes.…”

Improvement of fault interpretation with seismic attribute analysis of Jeju Basin, offshore southern Korea, East China Sea

“…The tensor attribute emphasizes edges that are detected by amplitude change and highlights amplitude terminations (McArdle et al, 2014). A high value of the tensor indicates a high likelihood of a fault plane.…”

“…Previous studies on the seismic attribute analysis were mainly conducted to visualize and interpret fault systems in seismic data by calculating numerous seismic attributes such as amplitude, frequency, phase, attenuation, and time (Chopra and Marfurt, 2007;Jibrin et al, 2013;Pigott et al, 2013;McArdle et al, 2014). In this study, dip, tensor, and structurally oriented semblance (SO semblance) attribute were generated to investigate the fault development patterns related to the rift evolution of the Jeju Basin, offshore southern Korea (East China Sea).…”

Exploring the seismic expression of fault zones in 3D seismic volumes

“…Faulkner 46 et al, 2010). So there is much interest in developing better interpretative tools for seismic data that 47 can predict the structure of complex fault zones, chiefly using seismic attributes (Chopra and 48 Marfurt, 2005;Cohen et al, 2006;Gao, 2003;Iacopini and Butler 2011;Iacopini et al 2012;McArdle et al, 2014;Botter et al, 2014;Hale, 2013 for a review; Marfurt and Alves, 2015). This contribution develops this theme further.…”