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Baig, Muhammad Zeeshan (ADNOC) | Van Laer, Pierre (ADNOC) | Leyrer, Karl (ADNOC) | Makrachev, Gennady (ADNOC) | Al Marzooqi, Hassan (ADNOC) | Al Suwaidi, Salama (ADNOC) | Raina, Ishan (Schlumberger) | Dasgupta, Suvodip (Schlumberger)
Abstract Diyab has served as the source rock for various major Jurassic and Cretaceous oil & gas plays in Middle East, and a number of recent studies have indicated that the Diyab formation has potential to be explored as an unconventional source rock gas play. This assessment is mainly based on 1) the known facies distribution, 2) lithology and rock properties, 3) source rock TOC and maturity 4) mud gas, and 5) Stimulation results. The objective of this paper is to identify the resource potential of Diyab source rock as an unconventional gas play in UAE. Integration of valuable measurements is of upmost importance to reduce the uncertainty in reservoir quality assessment of any exploration setting. Quantifying TOC and maturity are one of the most important aspects in evaluating the source rock potential of an unconventional play. Due to the complexities seen in several source rock plays, assessing quality through interpreting mineralogy, porosity and water saturation can also be quite challenging. To achieve that, a comprehensive mud logging analysis program was carried out in the well complemented with a comprehensive and modern logging program combined with a detailed unconventional core analysis to identify rock properties, fluid type and saturations with the scope to assess unconventional resource potential of the Diyab formation in UAE. Initial petrophysical evaluation shows that Diyab source rocks have a good Shale Gas resource potential within three different zones of interest in the Diyab formation. These zones of interest are based on, 1) Total Organic Carbon, 2) Porosity and 3) Saturation. During the petrophysical evaluation advanced mud logging analysis was used as initial calibration for TOC and mineralogy, a multi-frequency dielectric tool was used for initial saturation estimation and nuclear magnetic resonance analysis was used for porosity estimation and characterization. In the final computation, unconventional core analysis was used to refine and further calibrate the results. The level of gas saturation exceeds common pay criteria which are known to produce economic volumes of gas in other basins around the world. Diyab as a source rock and as unconventional gas play in UAE in terms of reservoir quality has never been studied in detail. This is the first time that this kind of a comprehensive evaluation program was carried out using advanced log acquisition, advanced mud logging and specific unconventional core analysis and through this paper important aspects of reservoir quality for Diyab formation will be discussed and will be of great help for future exploration plans in the Diyab unconventional gas play.
The unconventional revolution in North America has firmly established unconventional resource plays as an integral component of global hydrocarbon production. The established North American resource plays are heterogeneous and vary considerably in terms of play type, stratigraphic organization, and the lithology of the target unit. The Middle East has several world-class source rocks that have charged giant and supergiant conventional fields, which implies many opportunities to develop unconventional resource plays. Within this study, the stratigraphic organization of two prolific source rock intervals within the Early Silurian (Qusaiba Member) and Middle-Late Jurassic (Tuwaiq Mountain Formation and equivalents) is characterized from public-domain data sets. From this, a variety of unconventional plays are conceptualized within these resource intervals.
The systematic classification of established resource plays in North America facilitates analogue identification for these emerging resource intervals across the Middle East. The Montney play is identified as an analogue for the Silurian resource interval and can be used to help validate unproven unconventional play concepts. Within the Jurassic resource interval, multiple analogues are identified that characterize different aspects of the emerging unconventional play types. For instance, stratigraphic architecture within the emerging Tuwaiq Mountain shale play is comparable to the Vaca Muerta play of the Neuquén Basin in South America, while mineralogy is similar to that within the Eagle Ford play and porosity development is akin to the Marcellus play. Applying understanding from these analogues can enable more informed and efficient exploration, appraisal, and development decisions within these frontier and emerging Middle East resource plays.
This paper was prepared for presentation at the 8th Abu Dhabi International Petroleum Exhibition and Conference held in Abu Dhabi, U.A.E., 11-14 October 1998.
Ba Geri, Mohammed (Missouri University of Science and Technology) | Ellafi, Abdulaziz (University of North Dakota) | Flori, Ralph (Missouri University of Science and Technology) | Belhaij, Azmi (Saudi Metal Coating Company) | Alkamil, Ethar H. (University of Basrah)
Abstract Nowadays, as the worldwide consumption of hydrocarbon increases, while the conventional resources beings depleted, turning point toward unconventional reservoirs is crucial to producing more additional oil and gas from their massive reserves of hydrocarbon. As a result, exploration and operation companies gain attention recently for the investment in unconventional plays, such as shale and tight formations. A recent study by the U.S. Energy Information Administration (EIA) reported that the Middle East (ME) and North Africa (NF) region holds an enormous volume of recoverable oil and gas from unconventional resources. However, the evaluation process is at the early stage, and detailed information is still confidential with a limitation of the publication in terms of unconventional reservoirs potential. The objective of this research is to provide more information and build a comprehensive review of unconventional resources to bring the shale revolution to the ME and NF region. In addition, new opportunities, challenges, and risks will be introduced based on transferring acquiring experiences and technologies that have been applied in North American shale plays to similar formations in the ME and NF region. The workflow begins with reviewing and summarizing more than 100 conference papers, journal papers, and technical reports to gather detailed data on the geological description, reservoir characterization, geomechanical property, and operation history. Furthermore, simulation works, experimental studies, and pilot tests in the United States shale plays are used to build a database using the statistic approach to summarize and identify the range of parameters. The results are compared to similar unconventional plays in the region to establish guidelines for the exploration, development, and operation processes. This paper highlights the potential opportunities to access the unlocked formations in the region that holds substantial hydrocarbon resources.
Abstract Callovian-Kimmeridgian organic-rich carbonates (Hanifa Formation and equivalents) are exceptional source rocks that have generated substantial volumes of hydrocarbons and charged prolific conventional reservoirs across the Middle East. This stratigraphic interval is now also under appraisal as an unconventional play with a vast resource potential. An unconventional screening workflow, assessing organic-carbon content, maturity, thickness, and depth, has identified a considerable area that appears to be viable as an exploration target. To gain an understanding of the controls on sweet-spot distribution in this frontier unconventional play, it is necessary to consider a producing analogue. The Eagle Ford play in the Western Gulf, USA is commonly considered as a reservoir completion analogue because it has a comparable carbonate-dominated composition. However, the Eagle Ford play does not appear to be a pertinent exploration analogue because the geological criteria that control the distribution of sweet spots are fundamentally distinct from the Hanifa play. In this study, the emerging Vaca Muerta play in the Neuquén Basin, Argentina is considered to be a useful exploration analogue because its depositional architecture, stratigraphic variability, and composition are comparable to the Hanifa play. Sweet spots in the Vaca Muerta play are controlled by mechanical stratigraphy, which is related to the architecture and stratigraphic variability within the depositional system. Interval-specific production data from the Vaca Muerta Formation demonstrates that the best-performing units are not necessarily the most organic-rich, but relate to units with high frequency, cyclical intercalation of organic-rich units, and more brittle carbonate-dominated target horizons. The integration of seismic, well log, geomechanical, and production data demonstrates that sweet spots occur within progradational packages on the carbonate ramp. The best-performing areas (e.g., northwest sector at Loma Campana Block) intersect the lowstand systems tract where forced regression of the carbonate ramp induces reworking and detrital carbonate input into the anoxic basin. By upscaling these concepts, an unconventional exploration model can be formulated to guide regional sweet-spot prediction. The unconventional exploration model uses gross depositional environment maps, within the predictive framework of a sequence stratigraphic model, to identify the aerial extent of geomechanical sweet spots within each defined eustatic sequence. This is a valuable tool that can be used in conjunction with regional seismic data to identify potential sweet spots in both the Vaca Muerta play and the analogous Hanifa play.