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- Volume 37, Issue 6, 2019
First Break - Volume 37, Issue 6, 2019
Volume 37, Issue 6, 2019
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Potential to map soil salinity using inversion modelling of EM38 sensor data
AbstractSoil salinization limits agricultural productivity and can ultimately cause desertification and land abandonment. Traditionally soil salinity is assessed using soil sampling methods for laboratory determinations. These are not representative of soil properties at management scales and are highly time and work consuming, resulting in costly surveys. Recent research is revolutionizing how soil information can be obtained quickly and cheaply by using a state-of-the-art electromagnetic (EM) instrument and inversion techniques in conjunction with soil sampling results to generate high-resolution effective conductivity models and soil salinity maps. In this study, located in Leziria Grande, Portugal, an EM survey was performed at an experimental site to map the spatial variability of soil salinity. EM data were collected using an EM38 instrument deployed at different heights and orientations. The conductivity model obtained from joint inversion of EM data shows a high correlation with conductivity data from soil sampling. This has permitted the rapid development of a model of soil salinity.
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Seismic time reversal mirror experiment
Authors Evgeny Landa, Adi Yurman and Rob JenneskensAbstractTime Reversal Mirror (TRM) is a method for refocusing recorded waves (including seismic) to their initial source location. Using different observation geometries, we demonstrate how seismic P- and S- energy is successfully focused back to its original location in a field experiment. Focusing resolution is within the theoretical range of half the dominant wavelength. Although the field experiment is done in controlled conditions, a-priori knowledge of seismic velocities of the medium is not necessary. In the first step the seismic wave is generated by a sub-surface point source and recorded by a surface array (the mirror). In the second step, time-reversed traces are back-propagated from the original receiver positions and recorded at locations near and at the original source location. The ability to carry out seismic TRM is dependent on a new vibrator based on a linear synchronous motor (LSM). As opposed to standard hydraulic-based seismic vibrators, the LSM-based vibrator can generate an arbitrary signal and thus re-emit recorded seismic traces back into the sub-surface.
Various applications of the TRM in seismic data can be considered: enhance oil recovery by wave stimulation, fracking intensification, target oriented data acquisition etc.
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Selecting seismically safe formations for salt water disposal in the Delaware basin
Authors Zuzana Jechumtálová, Denis Anikiev and Leo EisnerAbstractAn increased level of seismicity in Delaware Basin generally from 2015 (West Texas and New Mexico, USA), and specifically in its southeast part near the city of Pecos from the year 2017 has opened up the question of whether it is induced or natural. Earthquakes can be induced either due to hydraulic fracturing designed to stimulate the production from tight shale formations, or by disposal of wastewater (Ellsworth, 2013). As the production from the Permian basin is rapidly growing, there are many new active injection wells (both hydraulic fracturing as well as salt water disposal wells) within this basin. As the detectability of seismic events increased (the result of the state-wide effort of TexNet network) some increase of reported seismicity can be attributed to the lower detection threshold for natural seismicity, but some increased seismicity can be due to hydraulic fracturing and some due to salt water disposal. The spatial and temporal relationship between injection rates and observed seismicity can be used to associate these earthquakes, origins.
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Emerging technologies applicable to increasing reservoir recovery factors
Authors Thomas Davis, Malcolm Wilson, Scott Wehner, John Vozniak, Paul Trost and Tom BrattonAbstractGeoscience disciplines such as geochemistry, geophysics, petrophysics and geomechanics play a critical role in reservoir management and do so over the extended life of the reservoir. Acoustic measurements comprising time-lapse seismic data and microseismic surveys provide a unique opportunity to monitor the flow of fluids and changing permeability fields. These surveys are incredibly rich in information because the measured data vary with changes in mineralogy, porosity, fluid saturation, fracture attributes, pore pressure and external stresses. Ultimately, their purpose is to economically increase the recovery factor from our reservoirs. Geoscientists and engineers using new and emerging technologies will have the means to increase the reservoir recovery factors of many of our reservoirs.
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An innovative approach to automation for velocity model building
Authors Tony Martin and Marcus BellAbstractWhile some efforts have been made to quantify structural uncertainty on seismic images (Osypov et al., 2011; Letki et al., 2013), the seismic data processing industry has found it challenging to measure the effectiveness of processing algorithms on seismic data. Understanding the success of a single algorithm may be time consuming, require significant work, including research and development, and is therefore also costly. Despite this, the demand for ‘error bars’ on processes is growing, while expectations are that projects should be completed faster. At the same time seismic projects are getting bigger. It is not uncommon to see projects recording up to 20,000,000,000,000 samples. For now, each project will typically have 15 to 20 major processing components, which are managed by intermediate data outputs, each having unique characteristics. More than any other industry, the seismic acquisition and processing companies should be at the forefront of big data analysis. However, there has been little progress from the industry in advanced analytics or artificial intelligence, and there has been no major effort in companies metamorphosing from geophysics to geophysical data science. Therefore, the innovation must come from within, by the geophysicists who use processing workflows on a daily basis. Modifications and manipulations to established systems enable advanced analytics, reductions in turnaround and the opportunity to provide confidence levels on output data volumes.
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Review of statistical probabilities from technologies used for pre-drill hydrocarbon prediction
More LessAbstractTo correctly rank prospects to make appropriate drill or drop decisions in hydrocarbon exploration, and to avoid personal biases, detailed processes have been developed.
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Hunting for Africa’s new transform play trends
Authors Karyna Rodriguez and Neil HodgsonAbstractThe abyssal plains of Africa’s passive margins have been inaccessible to drilling until recently, and traps for true basin floor fans little explored. Turbidite flows reaching the basin floor through confined slope channels can begin to lose energy and deposit coarser clastic components, although if the basin floor continues to gently slope down in an offshore or lateral direction then turbidite flows can continue for long distances. However, younger, hotter and more buoyant oceanic crust generally lies offshore from older, colder oceanic crust riding deeper on the mantle. This creates an up-dip-to-offshore (UDTO) geometry to the basin floor. UDTO basins, can therefore present opportunities for basin floor turbidite flows to onlap and form stratigraphic trapping geometries towards the offshore on oceanic crust. Yet such plays are often in water deeper than 3 km (i.e. the Early Cretaceous basin floor play under the Raya-1 well offshore Uruguay), unless the crust is supported by mantle convection (Yakaar-1 offshore Senegal).
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Using geophysics and geochemistry to find life in the solar system
More LessAbstractOn Earth, geophysical and geochemical data are used in the exploration and production of petroleum. Geophysical data are used to reveal what is below the Earth’s surface and where petroleum deposits may be located. Geochemical data are used to identify the chemistries and therefore potential petroleum products of organic-rich source rocks and to assess whether those source rocks are mature enough to have generated petroleum. Geochemical data are also used to correlate organic-rich source rocks with identified petroleum reservoirs to reveal possible migration routes and to reveal whether reservoirs are subdivided into compartments. In space, similar approaches are followed to search for past or present life on other planets and moons with geophysical methods revealing the environment and geochemical methods identifying the source of any organic matter.
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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)