Depositional history and reservoir characterisation of the Latest Devonian-Early Carboniferous Fairfield Group, northwestern Lennard Shelf, Canning Basin, Western Australia

[Truncated abstract] Detailed sedimentological analysis of core from 40 wells on the northwestern Lennard Shelf, northern Canning Basin, was undertaken to interpret the depositional history of the latest Devonian–Early Carboniferous carbonate-siliciclastic Fairfi eld Group within a sequence–stratigraphic framework. Integration of sedimentological and petrophysical interpretations with existing biostratigraphic data and new seismic interpretation was used to establish a geological model in which to examine the roles of depositional facies and diagenetic modifi cation on reservoir quality. The Fairfi eld Group is composed of fourteen facies associations (FA1- FA14) identifi ed from detailed sedimentological study of core. The majority of associations (FA1-FA9) were deposited on a broad inner ramp with open marine to restricted shallow subtidal– intertidal–supratidal conditions. FA1 represents a restricted supratidal area. Shallow subtidal–intertidal fenestral microbial mats and bioclastic facies (FA2) were widely developed on the platform and are typically dolomitised. Sandstones and siltstones represent deposition on tidal fl ats and in open marine areas (FA3 and FA4). Protected and restricted shallow subtidal areas on the platform are typically fi ne carbonate facies (FA5 and FA6). Bioclastic sediments were deposited in high energy zones as shoals (FA8 and FA9) and FA7 represents deposition intermediate to shoals and the protected lagoon.