Sequence stratigraphy as applied in its modern form had a significant initiation at the beginning of the 20th century. Based on Walther's actualistic understanding of facies development, A. W. Grabau developed an analysis of transgressive and regressive stratigraphic geometries in Palaeozoic successions of the north-eastern United States. This analysis of overlapping strata, e.g. facies, resembles a stratigraphic terminology that can be directly compared to the underpinnings of modern sequence stratigraphy. The discontinuation in developing Grabau's work is attributed to his personal biography, as well as the slow pace of acceptance and lack of application until the emergence of seismic stratigraphy in the 1970s. The publications have seen no major recognition in the academic community until today.

AbstractAcquisition of whole core data allows detailed rock typing profiles to be defined which are required to assign flow properties for dynamic reservoir simulation. Conventional core analysis provides lab measurements of porosity, permeability and pore size distribution sampled at plug locations with a limited sampling increment. Whole core CT scanning allows for a more continuous detailed evaluation of the cored intervals which allow the precise boundaries of specific Rock Types to be defined. This paper illustrates how novel techniques of data analysis and graphic displays of both whole core CT data and wireline NMR have been used to aid the definition of Rock Types and Flow Units.Rock Types have been categorized based on flow properties using plug porosity, permeability and MICP data. Processing of whole core CT data and wireline NMR has been performed in order to assess the heterogeneity measured by both acquisition methods. For the CT data set Heterogeneity Logs have been generated, these logs display the variation of CT density of the whole core. The logs have enabled very fine scale definition of lithotypes. In a similar manner the NMR logs were also analyzed and processed to extract specific statistical moments such as modes, magnitudes and skewness. Both sets of data were then integrated with core analysis data and thin sections. Excellent correlation between core plug, CT Heterogeneity Logs, NMR and thin section pore size distribution was observed and this has enabled the definition of Rock Types from the fine scale CT Heterogeneity Logs and Flow Units from the coarser scale wireline NMR data.The techniques described are applied to data from a heterogeneous evaporitic carbonate reservoir, where pore size distribution has a major effect on permeability and productivity. Eight Rock Types have been categorized from core analysis and these have been propagated from plug locations using the CT Heterogeneity Logs to assist manual interpretation. Neural Network and geostatistics were applied to propagate to uncored wells and throughout the geocellular model.The acquisition of core data and subsequent Heterogeneity Logs from whole core CT has proved very beneficial in the understanding of the wireline NMR tool response and has given confidence in the predictive ability of NMR to distinguish reservoir Flow Units in uncored intervals or wells.

Terrestrial LIDAR data were acquired at four sites in the Acacus Formation in southwestern Libya in order to better understand the sedimentary architecture and to create outcrop models to aid ongoing subsurface exploration. The outcrop models comprise up to 8 individual scans merged to produce panels up to 1.2 km wide and c. 200 in high. The panels highlight the gross stratigraphic architecture including shallowing- and coarsening-upwards cycles, major channel bodies, and subtle prograding units. The scan resolution was chosen to resolve the bed-scale stacking that typifies hydrocarbon reservoirs in this formation. Surfaces and facies observed in the outcrops and constrained by the LIDAR data were then used to construct 2-D synthetic seismic panels of the outcrop. These models were parameterized with densities and velocities from subsurface examples and used to gain insight into the seismic resolution of depositional architecture.

Outcropping cliffs of the Silurian Acacus Formation in Southern Libya were laser-scanned, and based on field sections mapped for reservoir bodies to resolve reservoir architecture. Pseudo-wells were constructed along these sections based on Jenein Sud well logs. Utilising seismic wavelet extractions accounting for frequencies and hence resolution, synthetic seismic sections were constructed to test the limits of seismic resolution for mapping Acacus reservoirs.

Continental sediments and geomorphological features of the coastal Wahiba Sands, Sultanate of Oman, reflect environmental variability in southeastern Arabia during the late Quaternary. Weakly cemented dune sands, interdune deposits and coastal sediments were dated by luminescence methods to establish an absolute chronology of changes in sedimentary dynamics. The dating results confirm previous assumptions that during times of low global sea level sand was transported by southerly winds from the exposed shelf onto the Arabian Peninsula. Two prominent phases of sand accumulation in the coastal area took place just before and after the last glacial maximum (LGM). A final significant period of dune consolidation is recognised during the early Holocene. However, no major consolidation of dunes appears to have occurred during the LGM and the Younger Dryas. In the northern part of the Wahiba Sands, these two periods are characterised by substantial sand deposition. This discrepancy is explained by the lack of conservation potential for dunes in the coastal area, probably caused by a low groundwater table due to low sea level and decreased precipitation. While the times of aeolian activity reflect arid to hyper‐arid conditions, lacustrine and pedogenically altered interdune deposits indicate wetter conditions than today caused by increased monsoonal circulation during the Holocene climatic optimum. Copyright © 2005 John Wiley & Sons, Ltd.

Invertebrate and trace fossil assemblages in wet interdune deposits of the Wahiba Sand Sea record environmental changes associated with the Indian Ocean Monsoon system during the Early Holocene wet period. This period is dated locally by infrared stimulated luminescence (IRSL) from ca. 9300 to 5500 years ago. Lacustrine deposits from interdune areas of the central sand sea developed during peak precipitation 9300 years (IRSL) ago. The deposits represent short-lived but permanent lakes characterized by salinity tolerant freshwater snails and ostracodes. Diverse trace fossils exposed on the present-day surface show that the dried out lake sediments became substrates for the dwelling, feeding, and reproductive activities of insects. This period of continued moist conditions with pronounced vegetation cover is recorded in post-lacustrine, wet interdune deposits from the coastal Wahiba Sand Sea. A 4-m thick succession of interdune deposits was dated to ca. 8500–5500 years (IRSL). This interdune succession shows intense bioturbation by rhizocretions and insect burrows and nests. Both sites of wet interdune deposits show that changes of moist conditions during the Early Holocene wet period can be monitored by a variety of biological indicators. The ecological information of in situ animal species and trace fossil assemblages adds to the understanding how climatic changes are expressed in continental environments.

Effects of the earliest Tethyan and Arctic-North Atlantic riftng phases on the Early Triassic succession of the Central European Basin are particularly well recordcd by unconformities, which form widespread sequence boundaries. Stratigraphic loss related to these unconformities may comprise entire Lower and Middle Buntsandstein formations most obviously developed in areas occupied by fault-controlled intra-basinal highs (swells). Analysis of 3D-seismic data and well logs combined with high-resolution sedimentological logging of drillcores at the western margin of the Ems Tough (NW Germany) reveals details of synsedimentary tectonic control on sequence development. Early Triassic extensional faulting of basement blocks provided stepwise addition of accommodation for continental sequences by growth faulting along north-south trending fault zones blocks on the flanks of the East Netherlands High. This process is most evident during the development of the Hardegsen Unconformity which is characterized by an amalgamation of succeeding unconformity surfaces in areas of structurally controlled intrabasinal highs. The mainly aeolian to playa-type sedimentary facies Q the Middle Buntsandstein succession suggests very low intrabasinal relief and implies a constant reworking and levelling Of the palaeo-surface. Consequently, the development and preservation of stratigraphic units is primarily deterinined by the potential accommodation provided by synsedimentary teconics.

The Late Permian/Early Triassic succession of the Central European Basin (CEB) was repeatedly affected by the tectonic pulses associated with the earliest phases of Tethyan and Arctic–North Atlantic rifting. Effects of the differential tectonic subsidence are particularly well recorded by unconformities, which form widespread sequence boundaries. Such unconformities are most obvious in areas occupied by fault-controlled intra-basinal highs (swells). In that areas, stratigraphic loss may comprise entire Lower and Middle Buntsandstein formations and in places remnant Middle Buntsandstein successions directly rest on Permian strata. Analysis of 3D-seismic data and well logs combined with high-resolution sedimentological logging of drillcores at the western margin of the Ems Trough (NW Germany) reveals details of synsedimentary tectonic control on sequence development. Early Triassic extensional faulting of basement blocks provided stepwise addition of accommodation space for continental sequences by growth faulting along north–south oriented fault zones blocks on the flanks of the East Netherlands High. This process is most evident during the development of the Hardegsen Unconformity, which is characterised by an amalgamation of succeeding unconformity surfaces in areas of structurally controlled intrabasinal highs.

Effects of the earliest Tethyan and Arctic-North Atlantic rifting phases on the Early Triassic succession of the Central European Basin are particularly well recorded by unconformities, which form widespread sequence boundaries. Stratigraphic loss related to these unconformities may comprise entire Lower and Middle Buntsandstein formations most obviously developed in areas occupied by fault-controlled intra-basinal highs (swells). Analysis of 3D-seismie data and well logs combined with high-resolution sedimentological logging of drillcores at the western margin of the Ems Trough (NW Germany) reveals details of synsedimentary tectonic control on sequence development. Early Triassic extensional faulting of basement blocks provided stepwise addition of accommodation for continental sequences bu growth faulting along north-south trending fault zones blocks on the flanks of the East Netherlands High. This process is most evident during the development of the Hardegsen Unconformity, which is characterized by an amalgamation of succeeding unconformity surfaces in areas of structurally controlled intrabasinul highs. The mainly aeolian to playa-type sedimentary facies of the Middle Buntsandstein succession suggests very low intrabasinal relief and implies a constant reworking and levelling of the palaeo-surface. Consequently, the development and preservation of stratigruphic units is primarily determined by the potential accommodation provided by synsedimentary tectonics.

Effects of the earliest Tethyan and Arctic-North Atlantic rifting phases on the Early Triassic succession of the Central European Basin are particularly well recorded by unconformities, which form widespread sequence boundaries. Stratigraphic loss related to these unconformities may comprise entire Lower and Middle Buntsandstein formations most obviously developed in areas occupied by fault-controlled intra-basinal highs (swells). Analysis of 3D-seismie data and well logs combined with high-resolution sedimentological logging of drillcores at the western margin of the Ems Trough (NW Germany) reveals details of synsedimentary tectonic control on sequence development. Early Triassic extensional faulting of basement blocks provided stepwise addition of accommodation for continental sequences bu growth faulting along north-south trending fault zones blocks on the flanks of the East Netherlands High. This process is most evident during the development of the Hardegsen Unconformity, which is characterized by an amalgamation of succeeding unconformity surfaces in areas of structurally controlled intrabasinul highs. The mainly aeolian to playa-type sedimentary facies of the Middle Buntsandstein succession suggests very low intrabasinal relief and implies a constant reworking and levelling of the palaeo-surface. Consequently, the development and preservation of stratigruphic units is primarily determined by the potential accommodation provided by synsedimentary tectonics.

Aeolian sand sea accumulations can serve as valuable archives of climate change in continental environments. The Wahiba Sand Sea is situated at the northern margin of the area presently affected by Indian Summer Monsoon Circulation and it records environmental changes associated with this major climatic boundary over the last 160 000 years. The internal stratigraphy and evolution of the sand sea is investigated using a combination of outcrop, borehole, seismic and luminescence data. Proximity to the Indian Ocean means that the sand sea succession shows the influence of sea level changes on the sedimentary architecture and composition of the dune deposits. During the last two glacial periods, low global sea level was associated with a high input of bioclastic grains, reflecting the significance of subaerially exposed shelf areas as one of the main sources of aeolian sediment. The onset of aeolian sediment transport and deposition was related to the breakdown of stabilizing vegetation during arid periods that equate with sea level lowstands. The preservation of aeolian sediments by the formation of supersurfaces and associated palaeosoils took place during times of increased wetness and elevated groundwater tables. This interplay of constructive and destructive periods greatly influenced the sedimentary architecture. Oscillations of wet and dry periods between 160 000 and 130 000 years and 120 000-105 000 years ago are attributed to the evolution of a wet aeolian system. Younger periods of aeolian deposition around and after the last glacial maximum were characterized by dry aeolian conditions. No soil horizons developed during these times.