Abstract Exploration and play types in rifted Atlantic margin basins occur in passive margin as well as failed rift settings. Offshore Brazil and Angola, the passive margin post-rift succession has been viewed as the most prolific, whereas in failed rift basins such as the North Sea basin, the pre-rift and syn-rift succession has had the highest success rate. In many passive margin basins, source and reservoir rocks are separated by thick autochthonous or allochthonous salt deposits. A major challenge is to understand source rock deposition, maturation, and migration of hydrocarbons: reservoir units often can be easily imaged on seismic data. Source rock deposition warrants new ideas, because seismic imaging below salt is poor. The understanding of source deposition often relies on low-resolution data such as gravity and magnetic data, or deep seismic data tuned towards identification of major structural lineaments. Thus, new play identification is clearly dependent on improved source rock understanding. On the contrary, in failed rifts, source rock deposition and migration are relatively well understood. Classic plays such as rotated fault blocks containing pre-rift reservoirs are well known and simple to identify. A future challenge lies in identification of less voluminous reservoirs in the syn-rift and early post-rift succession. Such plays may add significantly to otherwise declining reserves and prolong the life of existing installations.

Abstract This paper examines the stratal geometries and facies stacking patterns associated with forced regressions around fault-propagation folds in extensional and compressional settings. Case studies are documented from: (i) the Miocene of the Suez rift and (ii) the Eocene of the Ainsa piggyback basin, Pyrenees. Despite the different tectonic settings, the stratal geometries and facies stacking patterns are remarkably similar. Distinctive sharp-based shoreface sandstones, formed as a result of forced regression, were deposited around growth anticlines. The forced regressive shoreface sandstones ‘shale-out’ rapidly basinward away from the growth anticlines and sit abruptly within offshore mudstones of highstand (HST) and transgressive (TST) systems tracts along the flanks of the growth anticlines. As fold amplification proceeded, older sandbodies were rotated to dip more steeply, and there is commonly a 2–5° angular difference between successive forced regressive sandbodies. This progressive tilting, coupled with marine erosion during relative sea-level fall has completely removed HST and TST deposits near anticline crets, and led to vertical amalgamation of individual forced regressive sandbodies. The resulting stratal geometries clearly result from the tectonic enhancement of forced regression.