Abstract The purpose of this Seals Atlas is to present the microstructural, petrophysical, and geomechanical properties of selected examples of cap rocks and fault seals for use as analogs in the prediction of seal capacity or containment potential. Similar atlases exist; however, this is the first such atlas to focus specifically on the characteristics of cap rocks. The atlas is primarily based on extensive mercury injection capillary pressure (MICP) analyses, but also includes thin section, XRD, grainsize distribution, SEM/EDS, and 'V shale' data. The samples included in this atlas are a result of APCRC and CO2CRC (Cooperative Research Centres) research programs focusing on top and intraformational seals and some fault seals (cataclasites) throughout Australia and New Zealand. The hydrocarbon/carbon dioxide seal examples are grouped by basin localities and further distinguished by formation, well, then depth. Where multiple examples are available, a range of lithologies and MICP data are included in the sample selection. This atlas also can be used in an evaluation of integrated seal potential for prospect risking and reservoir management.

Coals of Cretaceous age are preserved within the fill of several Australian sedimentary basins. Presently, Cretaceous coal is mined in only one area, although numerous coalfields have been active over the past century. Cretaceous organic facies in the subsurface of the Gippsland Basin, offshore southeast Australia, are thought to have sourced the major oil and gas accumulations of that area. Cretaceous coal-bearing basins in Australia fall into four groups: interior basins, notably the Eromanga Basin where the greatest occurrence of coal is in the Cenomanian Winton Formation; east coast basins, including the Laura Basin (Late Jurassic to Early Cretaceous Battle Camp Formation), Styx Basin (Albiah to Cenomanian Styx Coal Measures), Stanwell Outlier (Albian Stanwell Coal Measures), and Maryborough Basin (Albian Burrum Coal Measures); south coast basins, notably the Great Australian Bight, Otway Basin (Otway and Sherbrook Groups), Bass Basin, (Otway and Eastern View Groups), and Gippsland Basin (Strzelecki and Latrobe Groups), where coal is known from throughout the Cretaceous system; west coast basins, notably the Perth Basin, which contains minor, Early Cretaceous coal. The major control on the formation and distribution of Cretaceous coal in Australia was the development of widespread, rapidly-subsiding lowland environments during passive margin breakup between Australia and Antarctica, and between Australia and Lord Howe Rise. The widespread stratigraphic distribution of coal resources suggests that fluctuating climate and evolving vegetational communities did not fundamentally affect coal development. The role of eustatic sea-level changes is difficult to assess at present. Within individual basins, structural regime and the distribution of depositional systems also played an active role in controlling coal distribution.