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- Volume 36, Issue 7, 2018
First Break - Volume 36, Issue 7, 2018
Volume 36, Issue 7, 2018
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Increasing confidence in reef interpretation using dip angle gathers analysis
AbstractThe uncertainty associated with the seismic interpretation of carbonate reef boundaries primarily relates to the generally limited difference between the velocities characterizing the reef body, and those of the encasing strata. In addition, the carbonate overburden section also generates strong multiple waves, whose physical characteristics are similar to those of the primary reflections, hindering the unequivocal identification of the latter. As a result, through conventional processing, it is often difficult to achieve a high signal-to-noise ratio and to confidently define the reef boundaries. Even employing industry-established, traditional seismic attributes a reef may just appear as a faint shadow or even not be visible. For a more confident interpretation of the reef we propose the adoption of an advanced methodology, based on analysis of dip angle gathers. Such an approach allows for a straightforward and reliable identification of the reef edges, reducing the uncertainties connected with their interpretation and possibly highlighting areas of different reservoir properties.
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Model-based interbed multiple attenuation: a case study of Najmah reservoir, North Kuwait Jurassic
Authors Noor C. Wibowo, Thomas L. Davis and Bruce VerWestAbstractThe Late Jurassic Najmah Formation of Northeast Kuwait consists of a fractured tight carbonate reservoir and organic-rich kerogen layer (Figure 1). Development of the Najmah reservoir is contingent on recognizing naturally fractured areas. Prior to seismic reservoir characterization, it is essential to ensure that the data quality is reliable before extracting any information from the seismic data. Noise contamination can obscure the reflections of interest, leading to inaccurate interpretation and the need for further data analysis for reservoir delineation. Data acquired in the study area indicates that P-wave seismic data within the reservoir interval suffers from the interference of coherent noise related to the interbed multiple. The interbed multiple is a serious problem that is common in the land seismic datasets in the Middle East (Al-Khaled et al., 2008; Al-Nahhas et al., 2008; El-Emam et al., 2011, 2005; Lesnikov and Owusu, 2011; Ras et al., 2012; Sonika et al., 2012; Wu et al. 2011).
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Using surface drilling data for a geologically and geomechanically constrained 3D planar frac simulator and fast reservoir simulation — application to engineered completions and well interference prevention
Authors A. Ouenes, D. Elmadhun, S. Soza, X. Li and R. SmaouiAbstractModelling unconventional reservoirs requires increasingly complex physics to describe the phenomena that affect the performance and efficiency of horizontal wells. For example, poroelastic geomechanical simulation (Ouenes et al., 2017b) is needed to model frac hits and well interferences resulting from the presence of stress and pressure dependent natural fractures and other geologic factors that see their permeability increase during stimulation. Recent field observations related to stress relaxation required the introduction of viscoelasticity (Peterson et al., 2018) to better understand the effect of timing during fracing. Lastly, the importance of interfaces and their impact on fracture height growth required the introduction of 3D damage mechanics (Aimene et al., 2018) to model the propagation of hydraulic fractures in a more realistic rock volume that considers the layering of the various lithologies and the resulting weak interfaces that will in turn interact with hydraulic fractures. This increasing complexity in physics is also combined with the need to provide solutions very quickly, if not in real time
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Advanced surface logging technology for unconventional plays: well-site applications in tight reservoirs
More LessAbstractRecently, significant improvements in Surface Logging technology have led to new methodologies for characterizing reservoirs. Such characterizations add significant value in both drilling and modelling activity and provide highly cost-effective well-site solutions: e.g. the chemical variations within rock sequences can be a powerful tool backing up or even replacing well logs used for well orientation.
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Mission Innovation task force reports on enabling Gigatonne-scale CO2 storage
Authors Phil Ringrose and Curt OldenburgAbstractA group of scientists from six countries (France, Netherlands, Norway, Saudi Arabia, UK and the US) met over three days in September 2017 in Houston, Texas, to brainstorm and debate the most promising research directions needed to make breakthroughs in the areas of injectivity and capacity that currently pose challenges to carrying out large-scale (gigatonnes CO2 per year) geologic carbon sequestration. Several CO2 storage projects around the world have demonstrated the feasibility of injecting and storing CO2 at the mega-tonne per year scale. These include the long-running Sleipner project (Norway) which started in 1996 and which has stored ∼17 Mt of CO2 to date, and the Illinois Basin Decatur Project (USA) which has stored approximately 1 Mt of CO2. New projects have started over the last few years, including the QUEST project in Canada, the Gorgon project in Australia, and the Industrial Carbon Capture and Storage (ICCS) project at Decatur, Illinois, which will inject 1 Mt CO2/yr. These projects along with a wealth of injection experience from the oil and gas industry over decades, supported by an extensive literature of theory and modelling analyses, provide confidence in the subsurface storage concept intrinsic to CCUS.
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Improved vertical stress profiling for unconventional reservoirs
Authors Tom Bratton and Mike SorokaAbstractA critical input in a hydraulic fracture stimulation design is the vertical stress profile. From it, designers can determine the variation in the minimum horizontal stress as a function of depth. The depth profile of the minimum horizontal stress (i.e., the vertical stress profile) is a major factor in controlling the geometry of a hydraulic fracture or fracture network development (e.g., Econo-mides and Nolte, 2000). For example, an optimum stimulation design would define the pumping variables and schedule so as to limit height growth to the productive interval while promoting optimum horizontal growth. Height growth into non-productive layers above or below the pay interval reduces the horizontal length in the productive interval. In addition, gravity can concentrate the proppant in the fractures below the producing interval, diminishing fracture conductivity in the producing interval. Both mechanisms decrease production. Therefore, to design an optimal stimulation, an accurate vertical stress profile is required. This requires appropriate and accurate stress models.
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Volumes & issues
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Volume 42 (2024)
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Volume 41 (2023)
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Volume 40 (2022)
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Volume 39 (2021)
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Volume 38 (2020)
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Volume 37 (2019)
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Volume 36 (2018)
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Volume 35 (2017)
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Volume 34 (2016)
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Volume 33 (2015)
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Volume 32 (2014)
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Volume 31 (2013)
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Volume 30 (2012)
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Volume 29 (2011)
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Volume 28 (2010)
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Volume 27 (2009)
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Volume 26 (2008)
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Volume 25 (2007)
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Volume 24 (2006)
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Volume 23 (2005)
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Volume 22 (2004)
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Volume 21 (2003)
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Volume 20 (2002)
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Volume 19 (2001)
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Volume 18 (2000)
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Volume 17 (1999)
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Volume 16 (1998)
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Volume 15 (1997)
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Volume 14 (1996)
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Volume 13 (1995)
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Volume 12 (1994)
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Volume 11 (1993)
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Volume 10 (1992)
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Volume 9 (1991)
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Volume 8 (1990)
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Volume 7 (1989)
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Volume 6 (1988)
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Volume 5 (1987)
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Volume 4 (1986)
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Volume 3 (1985)
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Volume 2 (1984)
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Volume 1 (1983)