The paper by Iyer et al. (pp 121–144) compares commonly‐used methods for estimating net erosion based on vitrinite reflectance (VR), temperature and sonic log (sonic velocity) data. Erosion estimates are vital for petroleum systems models, and the net erosion history may influence source rock maturation and the timing of hydrocarbon expulsion as well as diagenetic processes controlling reservoir properties and seal behavior. Methods to estimate erosion based on VR and sonic velocity are widely used as the required data‐sets are frequently available and provide independent results. These methods are reviewed and critically assessed, and reasons for differences in net erosion estimates for the same well (for example due to the influence of outliers in a VR data set, or to the influence of overpressuring on velocity data) are discussed. A novel, automated method for estimating erosion is then described. The method incorporates a 1D basin model which simulates sedimentation and burial at a well location through time; modelled VR, temperature and sonic velocity data are then compared with measured well data to reach a best possible fit, and an optimization algorithm is used to find the best solution for estimated net erosion and heat flux with respect to the input data. This new method is used to estimate net erosion at three wells located in the Norwegian Barents Sea. This area is thought to have undergone a number of Cenozoic erosional episodes and net erosion may exceed 2000 m in places.

Koyi and Mansurbeg (pp 145–166) review the role of multiple detachment surfaces in the structural deformation of the Zagros fold‐and‐thrust belt, with particular attention to parts of the foldbelt in the Kurdistan Region of northern Iraq and in SW Iran. Early studies of the Zagros drew attention to the importance of thick evaporites in the Infracambrian Hormuz Salt and Miocene Lower Fars Formations as décollements. For example at Kirkuk field, the Lower Fars Formation decouples structures in the overlying succession from those below. Koyi and Mansurbeg now show how multiple décollement horizons within the Zagros stratigraphy may serve to decouple over‐ and underlying structures in a similar way. The horizons may be composed of a variety of mechanically weak lithologies besides evaporites such as mudstones, marls and shales, all of which are present at different levels within the shortened Mesozoic and Cenozoic stratigraphy. Satellite, field and seismic data from different parts of the Zagros are interpreted in terms of the decoupling of structures at different depths formed during regional shortening, and in general are consistent with structures formed in laboratory analogue models. Folds in the competent successions above and below the weak horizons will have different wavelengths and amplitudes. Thus the coexistence in close proximity of surface anticlines with widely different widths and amplitudes suggests structural decoupling at multiple levels. Decoupling is of significance for prospect location because subsurface folds forming potential structural traps may be displaced laterally relative to anticlines present at the surface.

Hydrocarbons in the Oriente Basin, Ecuador, part of the sub‐Andean foreland basin system, are mainly reservoired in sandstones in the Campanian M1 Member of the Napo Formation. Previous studies have demonstrated that source rocks are organic‐rich lime mudstones and shales within the Napo Formation, from which oil and gas have migrated laterally up‐dip from deeply‐buried kitchens, sometimes over long distances. Ma et al. (pp 167–186) studied oil samples from 43 producing wells in the Block T area in the north of the Oriente Basin using GC and GC‐MS analyses in order to investigate the origin of the oils and the charge history. Results of the organic geochemical analyses were integrated with studies of oil‐ and gas‐bearing fluid inclusions from the M1 Sandstone reservoir. The results of the geochemical analyses show that oil samples contain a complete n‐alkane series with a main peak at C₁₅‐C₁₇ and a subordinate peak at C₂₅‐C₃₀. These and other biomarker characteristics indicate that the oils were derived from a source rock containing both aquatic algal and terrigenous higher plant material. The oils are interpreted to have been generated at early to peak maturities by a source rock deposited in a suboxic to anoxic setting, broadly consistent with previous studies. Homogenization temperatures of fluid inclusions range from 81 to 95°C; according to a burial history model, the M1 Sandstones reached these temperatures in the early Miocene when oil charging into the reservoir is therefore interpreted to have begun. However biodegradation of the early‐charged oils is then inferred to have taken place, as indicated by the prominent UCM humps in gas chromatograms and by the presence of the marker compound 25‐norhpane. Biodegraded, early oils with these characteristics coexist in the M1 Sandstone reservoir with fresh, unaltered oils which are interpreted to represent a second, more recent charge.

Samakinde et al. (pp 187–208) report the results of a 3D modelling study of Barremian‐Aptian source rocks in a shelfal to slope area in the northern part of the Orange Basin, offshore western South Africa, a region of increasing exploration interest. Organic‐rich Barremian – lower Aptian shales containing Type III kerogen were deposited in deep‐marine conditions in the Orange Basin as part of a transitional rift‐to‐drift sequence. The study was based on 2D and 3D seismic together with organic geochemical (and logging) data from three offshore wells which were used as inputs for a 3D model calibrated against vitrinite reflectance (VR) and Rock‐Eval T_max measurements. 1D temperature and vitrinite reflectance models for the three well locations show that there is in general a good fit between modelled and measured data although some relatively minor discrepancies occur. A 3D temperature model shows a general increase in modelled source rock temperatures to the south and west of the study area, and is broadly consistent with a present‐day 3D VR model which shows that the source rock is in the gas window to the south and thermally immature to the north (%R_∘ ∼1.0 and ∼0.5 respectively). Hydrocarbon generation is modelled to have begun at about 116 Ma (late Aptian) with expulsion from the source rock peaking in the latest Cretaceous – earliest Cenozoic. Migration modelling indicates that the direction of gas migration in mid‐Cretaceous sandstone carrier beds was effectively random; however migration of liquid oil was down‐dip (i.e. to the west), possibly due to the influence of hydrodynamic factors. Distal, deep‐water areas in the west of the Orange Basin should therefore be the focus of future exploration for oil plays.

Iyer等人的论文。（第121–144页）比较了基于镜质体反射率（VR），温度和声波测井（声速）数据估算净侵蚀的常用方法。侵蚀估算对于石油系统模型至关重要，其净侵蚀历史可能会影响烃源岩的成熟度，碳氢化合物驱出时间以及控制储层性质和密封性的成岩过程。由于所需的数据集经常可用并且提供独立的结果，因此广泛使用基于VR和声速估算侵蚀的方法。对这些方法进行了审查和严格评估，并讨论了同一口井的净侵蚀估算值差异的原因（例如，由于VR数据集中异常值的影响或过压对速度数据的影响）。一本小说，然后描述了估计侵蚀的自动方法。该方法结合了一维盆地模型，该模型可以模拟一段时间内井位的沉积和埋藏；然后将模型化的VR，温度和声速数据与测井数据进行比较，以达到最佳拟合效果，并使用优化算法为输入数据估算净侵蚀和热通量找到最佳解决方案。该新方法用于估算位于挪威巴伦支海的三口井的净侵蚀量。人们认为该地区经历了许多新生代侵蚀事件，某些地方的净侵蚀可能超过2000 m。然后将温度和声速数据与测井数据进行比较，以达到最佳拟合效果，并使用优化算法为输入数据找到最佳的估计净侵蚀和热通量的解决方案。该新方法用于估算位于挪威巴伦支海的三口井的净侵蚀量。人们认为该地区经历了许多新生代侵蚀事件，某些地方的净侵蚀可能超过2000 m。然后将温度和声速数据与测井数据进行比较，以达到最佳拟合效果，并使用优化算法为输入数据找到最佳的估计净侵蚀和热通量的解决方案。该新方法用于估算位于挪威巴伦支海的三口井的净侵蚀量。人们认为该地区经历了许多新生代侵蚀事件，某些地方的净侵蚀可能超过2000 m。

Koyi和Mansurbeg（pp 145–166）回顾了多个分离面在Zagros褶皱冲断带构造变形中的作用，尤其要注意伊拉克北部库尔德斯坦地区和伊朗西南部的褶皱带部分。Zagros的早期研究提请人们注意寒武纪Hormuz盐和中新世下Fars地层中稠密蒸发物的变质作用。例如，在基尔库克油田，下法尔斯组将上覆构造中的构造与下层构造分离。Koyi和Mansurbeg现在展示了多重脱节Zagros地层中的地层可能以类似的方式使上层和下层结构脱钩。除蒸发岩（如泥岩，泥灰岩和页岩）外，地层可能还由各种机械性弱的岩性组成，所有这些岩体在缩短的中生代和新生代地层中都以不同的水平存在。扎格罗斯不同地区的卫星，野外和地震数据是根据区域缩短过程中形成的不同深度结构的解耦来解释的，通常与实验室模拟模型中形成的结构一致。在较弱的视线之上和之下的主管演替过程中的褶皱将具有不同的波长和幅度。因此，宽度和幅度相差很大的表面背斜紧密共存，表明在多个层面上结构解耦。去耦对于找矿位置很重要，因为形成潜在构造圈闭的地下褶皱可能相对于地表背斜横向移动。

厄瓜多尔的Oriente盆地的碳氢化合物是次安第斯前陆盆地系统的一部分，主要储藏在Napo组的Campanian M1成员的砂岩中。先前的研究表明，烃源岩是那坡组内富含有机物的石灰泥岩和页岩，油气从深埋的厨房中沿横向向上倾斜，有时甚至远距离迁移。Ma等。（167-186页）使用GC和GC-MS分析研究了东方盆地北部T区块的43口生产井的油样，以调查油的来源和装油历史。有机地球化学分析的结果与M1砂岩油藏中含油气的流体包裹体的研究相结合。地球化学分析的结果表明，油样品包含一个完整的正烷烃系列中C的主峰₁₅ -C ₁₇中C和下级峰₂₅ -C ₃₀。这些和其他生物标志物特征表明，这些油是从含有水生藻类和陆生高等植物材料的烃源岩中提取的。认为这些油是在低氧至缺氧环境中沉积的烃源岩在早至顶峰成熟时产生的，与先前的研究大体一致。流体包裹体的均质温度范围为81至95°C；根据埋葬历史模型，M1砂岩在中新世早期就达到了这些温度，因此可以解释为已经开始向储层注油。但是，如气相色谱图中显着的UCM峰和标记化合物25-正庚烷的存在所表明的，然后推断早充油已发生了生物降解。生物降解的

萨马金德（Samakinde）等人。（第187–208页）报告了在南非西部沿海地区奥兰治盆地北部，陆架至斜坡地区的Barremian-Aptian烃源岩3D建模研究的结果，该地区是勘探兴趣不断增加的地区。富含有机物的Barremian-含III型干酪根的下Aptian页岩是深海条件下沉积在奥兰治盆地的一部分，是裂谷-漂移过程的一部分。这项研究基于2D和3D地震以及来自三个海上油井的有机地球化学（和测井）数据，这些数据被用作针对镜质体反射率（VR）和Rock-Eval T _max校准的3D模型的输入。测量。三个井位置的一维温度和镜质体反射率模型显示，尽管发生了一些相对较小的差异，但是在建模数据和测量数据之间通常具有很好的拟合度。3D温度模型显示了研究区域南部和西部的模拟烃源岩温度普遍升高，并且与当今的3D VR模型大致吻合，后者显示了烃源岩位于南部和南部的气窗中。北不热（％_R∘分别为〜1.0和〜0.5）。碳氢化合物的生成模型始于约116 Ma（阿普天晚期），源于最早的白垩纪-最早的新生代烃源岩驱出。运移模型表明，白垩纪中层砂岩运移床中的气体运移方向实际上是随机的。然而，液态油的运移下降了（即向西），这可能是由于流体动力因素的影响。因此，奥兰治盆地西部的深水深处地区应成为未来石油勘探的重点。