OMV and ADNOC signed a study agreement in 2013 to explore for hydrocarbons in a large (10,000km2) under-explored onshore area, named East Abu Dhabi. The objective of the work programme was to evaluate the conventional and unconventional hydrocarbon potential within multiple play types and structural settings, via the analysis of existing vintage data, acquisition of new seismic followed by exploration drilling. To date 1,800km2 3D (4S) and 700km 2D seismic have been acquired focused on two principal play types; namely, the ‘Pabdeh’ stratigraphic play and the ‘Thamama’ combined structural/stratigraphic play. Additional studies completed include fluid inclusion stratigraphy using data from nearby vintage wells, and the completion of an unconventional study covering the wider area of interest. The first OMV operated exploration well reached its TD in the Jurassic in March 2017. Two tests have been performed in Lower Cretaceous and Jurassic resulting in a dry sour gas discovery. The main results of the well that have an impact on the understanding of the regional geology can be summarized as follows: 1) Source Rock, three potential source rock intervals have been penetrated (Middle and Lower Cretaceous & Jurassic). 2) Reservoir, The middle Cretaceous has been found in a back-shoal facies with its suggested corresponding platform margin being located in close proximity to the South-West. The Aptian is represented by the classical Lower Shuaiba fm. and overlain by the Bab shales. No isolated platform has been encountered. 3) Clear stratigraphic and structural evidence supporting structural deformation of the Thamama Group during the Lower Cretaceous. Several distinct fault trends are evidenced from both the well data and 3D seismic depth slices. Understanding these faults and related fracture systems will be fundamental in understanding the play potential in the wider area. This is the first exploration well to be drilled in the area since the ‘80s. Multiple intervals of regional interest have been encountered spanning the massive loss circulation intervals of the Palaeocene, conventional and unconventional reservoir within the Middle Cretaceous, the entire Lower Cretaceous sequence and the Asab equivalents of the Upper Jurassic.
We aim to demonstrate the use of high-resolution sedimentological data during the early phase of the exploration cycle. The data reviewed included more than 1300 m of log sections taken North of Erbil. This was combined with field mapping, a microfacies study and the acquisition of routine core analysis data from plugs to provide a more complete analysis. Subsurface data included lithological information from two wells and 2D seismic lines with a total length of 487 Km.The study focussed on carbonate sequences including potential and known hydrocarbon reservoirs, notably the Qamchuqa-, the Shiranish-, the Khurmala-and the Pila Spi Formations. As a result a refined stratigraphic and depositional framework for the Lower Tertiary and Upper Mesozoic sequences has been established. The Cretaceous sequences analysed herein display a series of distinct lithofacies types ranging from shallow marine to deeper marine environments, which can be attributed to different main depositional complexes. The Paleogene sequences show a high diversity of lithotypes that relate to fluvial, fluvio-marine, mixed siliciclastic -carbonate shelf and inner platform depositional environments.Outcrop samples from both Tertiary and Cretaceous dolomites inherit the highest porosities thus presumably best reservoir quality in the subsurface. However, the effect of fracturing cannot be assessed in detail from surface data alone. A 3D facies model has proven useful in displaying the spatial relationship of the well and outcrop data. The display of facies probabilities improves the recognition of cyclicity within homogeneous dolomite sections. Possible extent and connectivity of geobodies could be assessed with the model.The results have been compared with, and put into a regional context with data from literature and proprietary selected subsurface data. The outcrop data have been incorporated into a workflow that supported other G&G subsurface disciplines during the exploration phase.
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