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.

Abstract The data used in the compilation of this atlas originate from research conducted by the CO2CRC seals research program and superceded the APCRC seals program. Similar atlases exist in other parts of the world, notably by Shell, Sneider and Reservoirs Inc., and Petrotech. This is the first such atlas to deal specifically with seals and even more specifically, Australian and New Zealand seals. The seals atlas is primarily based on extensive mercury-injection capillary-pressure (MICP) analyses that have been performed using a state-of-the-art Micromeritics Mercury Porosimeter. The samples included in this atlas are mainly from the research realm, as most commercial work is proprietary. In addition to MICP data, thin sections, x-ray diffraction analysis, grain-size distribution, scanning electron microscopy with energy dispersive x-ray spectroscopy, and shale volume are included. The hydrocarbon and carbon dioxide seal examples are grouped by basin localities (see location map) and further distinguished by formation, well, then depth if multiple examples were analyzed. Where multiple examples are available, a range of lithologies and MICP data are included in the sample selection.

Abstract M ercury-injection capillary-pressure (MICP) evaluation of reservoir lithologies, cap seals, intra-formational seals, and fault seals is conducted at the Australian School of Petroleum (ASP). MICP measurements may be integrated with seismic to microstruchrral data to provide a robust basis for interpretation of the reservoir potential, sealing capacity, and stabiliy and strength of individual strata.

Abstract The Bass Basin is a northwest-trending, intra- cratonic rift basin that underlies the Bass Strait region beffveen northern Tasmania and southern Victoria (Figure 8 ). The basin covers an area of approximately 42,000 km 2 (16, 216 mi 2 ), and is sepa-rated from the Offvay Basin to the west and northwest by the King Island High, and from the Gippsland Basin to the northeast by Flinders Island and the Bassian Rise. The orientation of rift-related extensional stresses in the Bass Basin has been proposed as north-northeast, resulting in a series of west to northwest-striking basement-controlled normal faults offset along strike by northeast-trending accommodation zones ( Etheridge et al., 1985 ; Young et al., 1991 ; Gunn et al., 1996; Lennon et al., 1999).

Abstract The foreland, Early Permian to Middle Triassic Bowen Basin of eastern Queensland occupies about 160,000 km 2 (61,766 mi 2 ), the southern half of which is covered by the Surat Basin (Figure 10 ). It has a maximum sediment thickness of about 10,000 m (32,808 ft) concentrated in two north-trending dep- ocenters, the Taroom trough to the east and the Denison trough to the west (Elliott, 1989). Deposition in the basin commenced during an Early Permian exten- sional phase, with fluvial and lacustrine sediments and volcanics being deposited in a series of half grabens in the east, while in the west a thick succession of coals and nonmarine clastics were being deposited (Cadman et al., 1998). Following rifting, a thermal subsidence phase extended from the middle Early to Late Permian, during which a basinwide transgression allowed deposition of deltaic and shallow-marine, predominantly clastic sediments as well as extensive coal mea sures. Foreland loading of the basin spread from east to west during the Late Permian, resulting in accelerated subsidence, which allowed the deposition of a very thick succession of Upper Permian marine and fluvial clastics, again with coal and Lower to Middle Triassic fluvial and lacustrine clastics. Sedimentation in the basin was terminated by Middle to Late Triassic contraction (Elliott, 1989).

Abstract The Carnarvon Basin is an epicratonic, faulted and folded Phanerozoic basin that encompasses more than 1000 km (621 mi) of the west and northwest coast of Western Australia (Figure 12 ).

Abstract The Cooper Basin, situated in central Australia, is entirely covered by the Mesozoic Eromanga Basin and contains sequences ranging from Pennsylvanian to the Late Triassic (Figure 14 ). The basin also contains a sequence that spans the Permian-Triassic boundary without a break in deposition (Gravestock and Jensen-Schmidt, 1998 ).

Abstract The Late Jurassic-Cenozoic Gippsland Basin is a large basin on the southeast margin of Australia's continental shelf offshore Victoria (Figure 17 ). About two-thirds of the basin lies offshore in mainly shallow water (<200 m; 656 ft), although in the Bass Canyon in the east, water depths exceed 3000 m (9843 ft). The basin overlies Paleozoic metasediments and consists of a central depocenter (the Central Deep) with up to 10 km (6 mi) of section, flanked by the north and south Strzelecki Terraces, in turn flanked by the north and south platforms (Bernecker and Partridge, 2001 ; Power et al., 2001 ). Initial rifting in the Early Cretaceous resulted in a complex system of grabens and half grabens, forming part of the southern rift system between Australia and Antarctica. Volcanogenic and nonmarine sediments up to 3000 m (9843 ft) thick were deposited during this phase (Bernecker and Partridge, 2001 ).

Abstract The Otway Basin is one of several passive margin-type basins found along the southern margin of Australia. It formed as a result of the Gondwana rifting during the Jurassic and Cretaceous that ultimately led to the separation of Antarctica and Australia ( Stagg et al., 1990 ). Early Mesozoic rifting evolution in the Otway Basin, and especially in the western Otway Basin, was characterized by the for-mation of a series of east-west trending, half grabens, which were controlled by steep, northward dipping, extensional faults ( Hill, 1995 ) (Figure 19 ). Onset of the major rifting phase in the Late Jurassic led to the development of the Robe, Colac, and Gellibrand troughs. The Penola Trough and most of the early half-grabens in the western part of the Victorian Otway Basin may have formed as oblique or transtensional rift segments. The sediments of the Otway Group, which consists of the Casterton, Pretty Hill, Laira, and Eumeralla formations (see examples from South Australia, Figure 19 ), were deposited in a range of syn-tectonic sedimentary environments ( Kopsen and Scholefield, 1990 ).

Abstract The Perth Basin is a north- to north-northwest-trending, onshore and offshore sedimentary basin extending about 1300 km (808 mi) along the southwestern margin of the Australian continent (Figure 21 ). This large (172,300 km 2 ; 66,525 mi 2 ), structurally complex basin formed during the separation of Australia and greater India in the Permian to Early Cretaceous. It includes a significant onshore component and extends offshore to the edge of continental crust in water depths of up to 4500 m (14,764 ft) ( Marshall et al., 1989 ; Crostella and Backhouse, 2000 ; Geoscience Australia, 2009c).

Abstract The Cambrian to Holocene Bonaparte Basin is a fan-shaped hydrocarbon-bearing basin extending over 270,000 km 2 (104,248 mi 2 ) in northwestern offshore and onshore Australia (Figure 23). Tae basin contains up to 15 km (9 mi) of sediments and has a multiphase history, comprising the southern Paleozoic and northern Mesozoic depocenters. Tae basin developed during two phases of Paleozoic extension and Late Triassic compression prior to the onset of Mesozoic extension (Mory, 1991; Baxter et al., 1997 ; Geoscience Australia, 2009d).

Abstract The geological background of the Taranaki Basin has been summarized from King and Thrasher (1996) at the Geological and Nuclear Sciences Institute, New Zealand. The basin occupies an area of 100,000 km 2 (38,610 mi 2 ) and is located on the west coast of the North Island of New Zealand (Figure 25). The basin has mostly evolved as a marine basin with an extensive erosional contact surface that formed in the Early to Middle Cretaceous, with the oldest basinal strata being deposited in the Middle Cretaceous.

Abstract SEM of a very well sorted, subangular felsic quart-zose sandstone. View: oblique/perpendicular to bedding. Scale bar: 200 μm.