Carbon Storage Characterisation Using Pre-Stack Depth Migration in Harvey, Western Australia
8 Pages Posted: 4 Apr 2019 Last revised: 27 Oct 2020
In 2013 a first-order assessment of the CO2 containment, for the South West Hub (SW Hub), suggested possible migration pathways across faults with potential for improving reservoir connectivity but also bypassing the primary and secondary seals (Langhi et al., 2013). The assessment was based on a geological model built upon sparse 2D seismic data with locally high uncertainties specific ally regarding the structural architecture. The following year regional 3D seismic data was acquired near Harvey, Western Australia. The survey proved to be of great importance for regional characterisation of the reservoir, identification of the large structures and key geological interfaces. Small to medium size, shallow structures were imaged using high-resolution (nested) 3D surveys. These nested surveys were acquired in 2015 at the Harvey 4 well and in 2017 at the Harvey 3 well locations. The results demonstrated that high-density surveys were important even at the characterisation stage and were crucial for development of a detailed static model. A pre-stack time migrated (PSTM) high-resolution cube and the attribute derived from it, such as coherency and impedance, enabled improved structural and stratigraphic analysis around Harvey 3 and 4 wells. To acurately model the distribution of paleosols, lenses of high clay content, which are assumed to serve as baffles for CO2 upward migration, a pre-stack depth migration (PSDM) and stochastic inverstion were attempted on the Harvey seismic data.
Keywords: Geological storage, geosequestration, pre-stack depth migration, tomography, inversion, studies, GHGT-14
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