High‐resolution crosswell imaging of a west Texas carbonate reservoir: Part 1—Project summary and interpretation

A carbon dioxide flood pilot is being conducted in a section of Chevron’s McElroy field in Crane County, west Texas. Prior to [Formula: see text] injection, two high‐frequency crosswell seismic profiles were recorded to investigate the use of seismic profiling for high‐resolution reservoir delineation and [Formula: see text] monitoring. These preinjection profiles provide the baseline for time‐lapse monitoring. Profile #1 was recorded between an injector well and an offset observation well at a nominal well‐to‐well distance of 184 ft (56 m). Profile #2 was recorded between a producing well and the observation well at a nominal distance of 600 ft (183 m). The combination of traveltime tomography and stacked CDP reflection amplitudes demonstrates how high‐frequency crosswell seismic data can be used to image both large and small scale heterogeneity between wells: Transmission traveltime tomography is used to image the large scale velocity variations; CDP reflection imaging is then used to image smaller scale impedance heterogeneities. The resolution capability of crosswell data is clearly illustrated by an image of the Grayburg‐San Andres angular unconformity, seen in both the P‐wave and S‐wave velocity tomograms and the reflection images. In addition to the imaging study, cores from an observation well were analyzed to support interpretation of the crosswell images and assess the feasibility of monitoring changes in [Formula: see text] saturation. The results of this integrated study demonstrate (1) the use of crosswell seismic profiling to produce a high‐resolution reservoir delineation and (2) the possibility for successful monitoring of [Formula: see text] in carbonate reservoirs. The crosswell data were acquired with a piezoelectric source and a multilevel hydrophone array. Both profiles, nearly 80 000 seismic traces, were recorded in approximately 80 hours using a new acquisition technique of shooting on‐the‐fly. This paper presents the overall project summary and interpretation of the results from the near‐offset profile.

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High‐resolution crosswell imaging of a west Texas carbonate reservoir: Part 5—Core analysis

Geophysics ◽

10.1190/1.1443810 ◽

1995 ◽

Vol 60 (3) ◽

pp. 712-726 ◽

Cited By ~ 13

Author(s):

Richard C. Nolen‐Hoeksema ◽

Zhijing Wang ◽

Jerry M. Harris ◽

Robert T. Langan

Keyword(s):

Wave Velocity ◽

Field Experiments ◽

Velocity Ratio ◽

Carbonate Reservoir ◽

P Wave ◽

Core Analysis ◽

S Wave ◽

Traveltime Tomography ◽

West Texas ◽

P Wave Velocity

We conducted a core analysis program to provide supporting data to a series of crosswell field experiments being carried out in McElroy Field by Stanford University’s Seismic Tomography Project. The objective of these experiments is to demonstrate the use of crosswell seismic profiling for reservoir characterization and for monitoring [Formula: see text] flooding. For these west Texas carbonates, we estimate that [Formula: see text] saturation causes P‐wave velocity to change by −1.9% (pooled average, range = −6.3 to +0.1%), S‐wave velocity by +0.6% (range = 0 to 2.7%), and the P‐to‐S velocity ratio by −2.4% (range = −6.4 to −0.3%). When we compare these results to the precisions we can expect from traveltime tomography (about ±1% for P‐ and S‐wave velocity and about ±2% for the P‐to‐S velocity ratio), we conclude that time‐lapse traveltime tomography is sensitive enough to resolve changes in the P‐wave velocity, S‐wave velocity, and P‐to‐S velocity ratio that result from [Formula: see text] saturation. We concentrated here on the potential for [Formula: see text] saturation to affect seismic velocities. The potential for [Formula: see text] saturation to affect other seismic properties, not discussed here, may prove to be more significant (e.g., P‐wave and S‐wave impedance).

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Bottom-pressure observations of deep-sea internal hydrostatic and non-hydrostatic motions

Journal of Fluid Mechanics ◽

10.1017/jfm.2012.507 ◽

2013 ◽

Vol 714 ◽

pp. 591-611 ◽

Cited By ~ 5

Author(s):

Hans van Haren

Keyword(s):

Hydrostatic Pressure ◽

High Resolution ◽

Internal Waves ◽

High Frequency ◽

Large Scale ◽

Temperature Data ◽

Large Reynolds Number ◽

Small Scale ◽

Bottom Pressure ◽

Sloping Bottom

AbstractIn the ocean, sloping bottom topography is important for the generation and dissipation of internal waves. Here, the transition of such waves to turbulence is demonstrated using an accurate bottom-pressure sensor that was moored with an acoustic Doppler current profiler and high-resolution thermistor string on the sloping side of the ocean guyot ‘Great Meteor Seamount’ (water depth 549 m). The site is dominated by the passage of strong frontal bores, moving upslope once or twice every tidal period, with a trail of high-frequency internal waves. The bore amplitude and precise timing of bore passage vary every tide. A bore induces mainly non-hydrostatic pressure, while the trailing waves induce mainly internal hydrostatic pressure. These separate (internal wave) pressure terms are independently estimated using current and temperature data, respectively. In the bottom-pressure time series, the passage of a bore is barely visible, but the trailing high-frequency internal waves are. A bore is obscured by higher-frequency pressure variations up to ${\sim} 4{\times} 1{0}^{3} ~\mathrm{cpd} \approx 80N$ (cpd, cycles per day; $N$, the large-scale buoyancy frequency). These motions dominate the turbulent state of internal tides above a sloping bottom. In contrast with previous bottom-pressure observations in other areas, infra-gravity surface waves contribute little to these pressure variations in the same frequency range. Here, such waves do not incur observed pressure. This is verified in a consistency test for large-Reynolds-number turbulence using high-resolution temperature data. The high-frequency quasi-turbulent internal motions are visible in detailed temperature and acoustic echo images, revealing a nearly permanently wave-turbulent tide going up and down the bottom slope. Over the entire observational period, the spectral slope and variance of bottom pressure are equivalent to internal hydrostatic pressure due to internal waves in the lower 100 m above the bottom, by non-hydrostatic pressure due to high-frequency internal waves and large-scale overturning. The observations suggest a transition between large-scale internal waves, small-scale internal tidal waves residing on thin (${{\sim} }1~\mathrm{m} $) stratified layers and turbulence.

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Circum-nuclear molecular disks: Role in AGN fueling and feedback

Proceedings of the International Astronomical Union ◽

10.1017/s1743921320001544 ◽

2019 ◽

Vol 15 (S359) ◽

pp. 312-317

Author(s):

Francoise Combes

Keyword(s):

Black Hole ◽

Angular Momentum ◽

High Resolution ◽

Large Scale ◽

Active Galaxy ◽

Small Scale ◽

Massive Black Hole ◽

Molecular Outflows ◽

Molecular Outflow

AbstractGas fueling AGN (Active Galaxy Nuclei) is now traceable at high-resolution with ALMA (Atacama Large Millimeter Array) and NOEMA (NOrthern Extended Millimeter Array). Dynamical mechanisms are essential to exchange angular momentum and drive the gas to the super-massive black hole. While at 100pc scale, the gas is sometimes stalled in nuclear rings, recent observations reaching 10pc scale (50mas), may bring smoking gun evidence of fueling, within a randomly oriented nuclear gas disk. AGN feedback is also observed, in the form of narrow and collimated molecular outflows, which point towards the radio mode, or entrainment by a radio jet. Precession has been observed in a molecular outflow, indicating the precession of the radio jet. One of the best candidates for precession is the Bardeen-Petterson effect at small scale, which exerts a torque on the accreting material, and produces an extended disk warp. The misalignment between the inner and large-scale disk, enhances the coupling of the AGN feedback, since the jet sweeps a large part of the molecular disk.

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Climate SPHINX: evaluating the impact of resolution and stochastic physics parameterisations in the EC-Earth global climate model

Geoscientific Model Development ◽

10.5194/gmd-10-1383-2017 ◽

2017 ◽

Vol 10 (3) ◽

pp. 1383-1402 ◽

Cited By ~ 35

Author(s):

Paolo Davini ◽

Jost von Hardenberg ◽

Susanna Corti ◽

Hannah M. Christensen ◽

Stephan Juricke ◽

...

Keyword(s):

High Resolution ◽

Large Scale ◽

Climate Model ◽

Global Climate ◽

Rainfall Variability ◽

Global Climate Model ◽

Small Scale ◽

Low Resolution ◽

The Impact ◽

Stochastic Physics

Abstract. The Climate SPHINX (Stochastic Physics HIgh resolutioN eXperiments) project is a comprehensive set of ensemble simulations aimed at evaluating the sensitivity of present and future climate to model resolution and stochastic parameterisation. The EC-Earth Earth system model is used to explore the impact of stochastic physics in a large ensemble of 30-year climate integrations at five different atmospheric horizontal resolutions (from 125 up to 16 km). The project includes more than 120 simulations in both a historical scenario (1979–2008) and a climate change projection (2039–2068), together with coupled transient runs (1850–2100). A total of 20.4 million core hours have been used, made available from a single year grant from PRACE (the Partnership for Advanced Computing in Europe), and close to 1.5 PB of output data have been produced on SuperMUC IBM Petascale System at the Leibniz Supercomputing Centre (LRZ) in Garching, Germany. About 140 TB of post-processed data are stored on the CINECA supercomputing centre archives and are freely accessible to the community thanks to an EUDAT data pilot project. This paper presents the technical and scientific set-up of the experiments, including the details on the forcing used for the simulations performed, defining the SPHINX v1.0 protocol. In addition, an overview of preliminary results is given. An improvement in the simulation of Euro-Atlantic atmospheric blocking following resolution increase is observed. It is also shown that including stochastic parameterisation in the low-resolution runs helps to improve some aspects of the tropical climate – specifically the Madden–Julian Oscillation and the tropical rainfall variability. These findings show the importance of representing the impact of small-scale processes on the large-scale climate variability either explicitly (with high-resolution simulations) or stochastically (in low-resolution simulations).

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Climate SPHINX: evaluating the impact of resolution and stochastic physics parameterisations in climate simulations

10.5194/gmd-2016-115 ◽

2016 ◽

Cited By ~ 5

Author(s):

Paolo Davini ◽

Jost von Hardenberg ◽

Susanna Corti ◽

Hannah M. Christensen ◽

Stephan Juricke ◽

...

Keyword(s):

High Resolution ◽

Large Scale ◽

Rainfall Variability ◽

Pilot Project ◽

Small Scale ◽

Low Resolution ◽

Climate Simulations ◽

Advanced Computing ◽

The Impact ◽

Stochastic Physics

Abstract. The Climate SPHINX (Stochastic Physics HIgh resolutioN eXperiments) project is a comprehensive set of ensemble simulations aimed at evaluating the sensitivity of present and future climate to model resolution and stochastic parameterisation. The EC-Earth Earth-System Model is used to explore the impact of stochastic physics in a large ensemble of 30-year climate integrations at five different atmospheric horizontal resolutions (from 125 km up to 16 km). The project includes more than 120 simulations in both a historical scenario (1979–2008) and a climate change projection (2039–2068), together with coupled transient runs (1850–2100). A total of 20.4 million core hours have been used, made available from a single year grant from PRACE (the Partnership for Advanced Computing in Europe), and close to 1.5 PBytes of output data have been produced on SuperMUC IBM Petascale System at the Leibniz Supercomputing Center (LRZ) in Garching, Germany. About 140 TBytes of post-processed data are stored on the CINECA supercomputing center archives and are freely accessible to the community thanks to an EUDAT Data Pilot project. This paper presents the technical and scientific setup of the experiments, including the details on the forcing used for the simulations performed, defining the SPHINX v1.0 protocol. In addition, an overview of preliminary results is given: an improvement in the simulation of Euro-Atlantic atmospheric blocking following resolution increases is observed. It is also shown that including stochastic parameterisation in the low resolution runs helps to improve some aspects of the tropical climate – specifically the Madden-Julian Oscillation and the tropical rainfall variability. These findings show the importance of representing the impact of small scale processes on the large scale climate variability either explicitly (with high resolution simulations) or stochastically (in low resolution simulations).

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High resolution cross‐well imaging of a west texas carbonate reservoir: Part 1. Data acquisition and project overview

10.1190/1.1822089 ◽

1992 ◽

Cited By ~ 3

Author(s):

J. M. Harris ◽

Richard Nolen‐Hoeksema ◽

J. W. Rector ◽

M. Van Schaack ◽

S. K. Lazaratos

Keyword(s):

High Resolution ◽

Data Acquisition ◽

Carbonate Reservoir ◽

West Texas

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Dependence of Model Energy Spectra on Vertical Resolution

Monthly Weather Review ◽

10.1175/mwr-d-15-0316.1 ◽

2016 ◽

Vol 144 (4) ◽

pp. 1407-1421 ◽

Cited By ~ 9

Author(s):

Michael L. Waite

Keyword(s):

High Resolution ◽

Large Scale ◽

Vertical Mixing ◽

Energy Spectra ◽

Small Scale ◽

Rossby Number ◽

Vertical Resolution ◽

Wide Range ◽

Qualitative Shape ◽

Vertical Grid

Abstract Many high-resolution atmospheric models can reproduce the qualitative shape of the atmospheric kinetic energy spectrum, which has a power-law slope of −3 at large horizontal scales that shallows to approximately −5/3 in the mesoscale. This paper investigates the possible dependence of model energy spectra on the vertical grid resolution. Idealized simulations forced by relaxation to a baroclinically unstable jet are performed for a wide range of vertical grid spacings Δz. Energy spectra are converged for Δz 200 m but are very sensitive to resolution with 500 m ≤ Δz ≤ 2 km. The nature of this sensitivity depends on the vertical mixing scheme. With no vertical mixing or with weak, stability-dependent mixing, the mesoscale spectra are artificially amplified by low resolution: they are shallower and extend to larger scales than in the converged simulations. By contrast, vertical hyperviscosity with fixed grid-scale damping rate has the opposite effect: underresolved spectra are spuriously steepened. High-resolution spectra are converged except for the stability-dependent mixing case, which are damped by excessive mixing due to enhanced shear over a wide range of horizontal scales. It is shown that converged spectra require resolution of all vertical scales associated with the resolved horizontal structures: these include quasigeostrophic scales for large-scale motions with small Rossby number and the buoyancy scale for small-scale motions at large Rossby number. It is speculated that some model energy spectra may be contaminated by low vertical resolution, and it is recommended that vertical-resolution sensitivity tests always be performed.

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High Resolution Model Intercomparison Project (HighResMIP)

10.5194/gmd-2016-66 ◽

2016 ◽

Cited By ~ 5

Author(s):

R. J. Haarsma ◽

M. Roberts ◽

P. L. Vidale ◽

C. A. Senior ◽

A. Bellucci ◽

...

Keyword(s):

High Resolution ◽

Large Scale ◽

Computational Cost ◽

Horizontal Resolution ◽

Small Scale ◽

Model Intercomparison ◽

Resolution Model ◽

Intercomparison Project ◽

High Resolution Model ◽

The Impact

Abstract. Robust projections and predictions of climate variability and change, particularly at regional scales, rely on the driving processes being represented with fidelity in model simulations. The role of enhanced horizontal resolution in improved process representation in all components of the climate system is of growing interest, particularly as some recent simulations suggest the possibility for significant changes in both large-scale aspects of circulation, as well as improvements in small-scale processes and extremes. However, such high resolution global simulations at climate time scales, with resolutions of at least 50 km in the atmosphere and 0.25° in the ocean, have been performed at relatively few research centers and generally without overall coordination, primarily due to their computational cost. Assessing the robustness of the response of simulated climate to model resolution requires a large multi-model ensemble using a coordinated set of experiments. The Coupled Model Intercomparison Project 6 (CMIP6) is the ideal framework within which to conduct such a study, due to the strong link to models being developed for the CMIP DECK experiments and other MIPs. Increases in High Performance Computing (HPC) resources, as well as the revised experimental design for CMIP6, now enables a detailed investigation of the impact of increased resolution up to synoptic weather scales on the simulated mean climate and its variability. The High Resolution Model Intercomparison Project (HighResMIP) presented in this paper applies, for the first time, a multi-model approach to the systematic investigation of the impact of horizontal resolution. A coordinated set of experiments has been designed to assess both a standard and an enhanced horizontal resolution simulation in the atmosphere and ocean. The set of HighResMIP experiments is divided into three tiers consisting of atmosphere-only and coupled runs and spanning the period 1950-2050, with the possibility to extend to 2100, together with some additional targeted experiments. This paper describes the experimental set-up of HighResMIP, the analysis plan, the connection with the other CMIP6 endorsed MIPs, as well as the DECK and CMIP6 historical simulation. HighResMIP thereby focuses on one of the CMIP6 broad questions: “what are the origins and consequences of systematic model biases?”, but we also discuss how it addresses the World Climate Research Program (WCRP) grand challenges.

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Large-Scale Production of Bioactive Terrein by Aspergillus terreus Strain S020 Isolated from the Saudi Coast of the Red Sea

Biomolecules ◽

10.3390/biom9090480 ◽

2019 ◽

Vol 9 (9) ◽

pp. 480 ◽

Cited By ~ 5

Author(s):

Hani Z. Asfour ◽

Zuhier A. Awan ◽

Alaa A. Bagalagel ◽

Mahmoud A. Elfaky ◽

Reda F. A. Abdelhameed ◽

...

Keyword(s):

Mass Spectrometry ◽

High Resolution ◽

Crude Extract ◽

Large Scale ◽

Aspergillus Terreus ◽

Antimicrobial Activities ◽

Carcinoma Cells ◽

Small Scale ◽

Scale Production ◽

Fungal Strains

The diversity of symbiotic fungi derived from two marine sponges and sediment collected off Obhur, Jeddah (Saudi Arabia), was investigated in the current study. A total of 23 isolates were purified using a culture-dependent approach. Using the morphological properties combined with internal transcribed spacer-rDNA (ITS-rDNA) sequences, 23 fungal strains (in the majority Penicillium and Aspergillus) were identified from these samples. The biological screening (cytotoxic and antimicrobial activities) of small-scale cultures of these fungi yielded several target fungal strains which produced bioactive secondary metabolites. Amongst these isolates, the crude extract of Aspergillus terreus strain S020, which was cultured in fermentation static broth, 21 L, for 40 days at room temperature on potato dextrose broth, displayed strong antimicrobial activities against Pseudomonas aeruginosa and Staphylococcus aureus and significant antiproliferative effects on human carcinoma cells. Chromatographic separation of the crude extract by silica gel column chromatography indicated that the S020 isolate could produce a series of chemical compounds. Among these, pure crystalline terrein was separated with a high yield of 537.26 ± 23.42 g/kg extract, which represents the highest fermentation production of terrein to date. Its chemical structure was elucidated on the basis of high-resolution electrospray ionization mass spectrometry (HRESIMS) or high-resolution mass spectrometry (HRMS), 1D, and 2D NMR spectroscopic analyses and by comparison with reported data. The compound showed strong cytotoxic activity against colorectal carcinoma cells (HCT-116) and hepatocellular carcinoma cells (HepG2), with IC50 values of 12.13 and 22.53 µM, respectively. Our study highlights the potential of A. terreus strain S020 for the industrial production of bioactive terrein on a large scale and the importance of future investigations of these strains to identify the bioactive leads in these fungal extracts.

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Characterising the surface magnetic fields of T Tauri stars with high-resolution near-infrared spectroscopy

Astronomy and Astrophysics ◽

10.1051/0004-6361/201935695 ◽

2019 ◽

Vol 630 ◽

pp. A99 ◽

Cited By ~ 5

Author(s):

A. Lavail ◽

O. Kochukhov ◽

G. A. J. Hussain

Keyword(s):

Magnetic Field ◽

High Resolution ◽

Magnetic Fields ◽

Large Scale ◽

Near Infrared ◽

Field Measurements ◽

T Tauri Stars ◽

Small Scale ◽

Surface Magnetic Field ◽

T Tauri

Aims. In this paper, we aim to characterise the surface magnetic fields of a sample of eight T Tauri stars from high-resolution near-infrared spectroscopy. Some stars in our sample are known to be magnetic from previous spectroscopic or spectropolarimetric studies. Our goals are firstly to apply Zeeman broadening modelling to T Tauri stars with high-resolution data, secondly to expand the sample of stars with measured surface magnetic field strengths, thirdly to investigate possible rotational or long-term magnetic variability by comparing spectral time series of given targets, and fourthly to compare the magnetic field modulus ⟨B⟩ tracing small-scale magnetic fields to those of large-scale magnetic fields derived by Stokes V Zeeman Doppler Imaging (ZDI) studies. Methods. We modelled the Zeeman broadening of magnetically sensitive spectral lines in the near-infrared K-band from high-resolution spectra by using magnetic spectrum synthesis based on realistic model atmospheres and by using different descriptions of the surface magnetic field. We developped a Bayesian framework that selects the complexity of the magnetic field prescription based on the information contained in the data. Results. We obtain individual magnetic field measurements for each star in our sample using four different models. We find that the Bayesian Model 4 performs best in the range of magnetic fields measured on the sample (from 1.5 kG to 4.4 kG). We do not detect a strong rotational variation of ⟨B⟩ with a mean peak-to-peak variation of 0.3 kG. Our confidence intervals are of the same order of magnitude, which suggests that the Zeeman broadening is produced by a small-scale magnetic field homogeneously distributed over stellar surfaces. A comparison of our results with mean large-scale magnetic field measurements from Stokes V ZDI show different fractions of mean field strength being recovered, from 25–42% for relatively simple poloidal axisymmetric field topologies to 2–11% for more complex fields.

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