Abstract In many compressive zones, there is a risk of undercharged hydrocarbon prospects as a result of timing, that is, the growth of the structure is younger than the main fluid migration phase. The North Ucayali Basin represents a setting of this type, where locating the earliest structures is crucial for well placement. In the North Ucayali Basin, the variable amount of erosion at the top of the structures shows that they are not uniformly recent. Although the growth of early structures may be explained by the reactivation of inherited features during shortening, evaporitic pillows may represent an alternative factor controlling the localization of deformation in the studied area. Indeed, subsurface data reveal the presence of flat salt domes that have an influence on thrust localization. The existence and tips of such efficient gliding surfaces concentrate the strain and, as a result, localize the early zones of deformation. Analogue models designed to study these phenomena highlight the crucial role of salt pillows as potential weak zones localizing deformation ahead of the propagating wedge. These models also emphasize the need to constrain certain parameters that have been previously disregarded, including the thickness of the brittle layers between the main décollement level (if present) and the pillows, as well as their burial depth.

Abstract Basin modelling tools are now more efficient to reconstruct palinspastic structural cross sections and compute the history of temperature, pore-fluid pressure and fluid flow circulations in complex structural settings. In many cases and especially in areas where limited erosion occurred, the use of well logs, bottom hole temperatures (BHT) and palaeo-thermometers such as vitrinite reflectance (Ro) and Rock-Eval (Tmax) data is usually sufficient to calibrate the heat flow and geothermal gradients across a section. However, in the foothills domains erosion is a dominant process, challenging the reconstruction of reservoir rocks palaeo-burial and the corresponding calibration of their past thermal evolution. Often it is not possible to derive a single solution for palaeo-burial and palaeo-thermal gradient estimates in the foothills, if based solely on maturity ranks of the organic matter. Alternative methods are then required to narrow down the error bars in palaeo-burial estimates, and to secure more realistic predictions of hydrocarbon generation. Apatite fission tracks (AFT) can provide access to time–temperature paths and absolute ages for the crossing of the 120 °C isotherm and timing of the unroofing. Hydrocarbon-bearing fluid inclusions, when developing contemporaneously with aqueous inclusions, can provide a direct access to the pore-fluid temperature and pressure of cemented fractures or reservoir at the time of cementation and hydrocarbon trapping, on line with the tectonic evolution. Further attempts are also currently made to use calcite twins for constraining reservoir burial and palaeo-stress conditions during the main deformational episodes. Ultimately, the use of magnetic properties and petrographical measurements can also document the impact of tectonic stresses during the evolution of the layer parallel shortening (LPS). The methodology integrating these complementary constraints will be illustrated using reference case studies from Albania, sub-Andean basins in Colombia and Venezuela, segments of the North American Cordillera in Mexico and in the Canadian Rockies, as well as from the Middle East.