Imaging ahead of and around the bit in a desert environment: DrillCAM field trial with wireless geophones and top-drive sensor

2021 ◽  
Vol 40 (5) ◽  
pp. 374-381
Author(s):  
Ali Aldawood ◽  
Emad Hemyari ◽  
Ilya Silvestrov ◽  
Andrey Bakulin
Keyword(s):  
Real Time ◽  
Land Surface ◽  
Velocity Model ◽  
Desert Environment ◽  
Drilling Depth ◽  
Data Set ◽  
Near Surface ◽  
The North ◽  
Noise Data ◽  
East West

Advanced seismic-while-drilling (SWD) technologies are being utilized to steer drilling operations and provide high-resolution subsurface images around and ahead of the bit. We present a case study of SWD imaging using a recently acquired field data set from a desert environment with a complex near surface. Data acquisition is performed with wireless geophones and top-drive sensors using continuous real-time recording. The drill-bit noise data are analyzed while continuously recording in real time by using a specialized workflow that combines elements of SWD and conventional vertical seismic profiling processing with controlled seismic sources. First, the workflow enhances the direct wavefield to retrieve accurate first-break picks for traveltime tomographic inversion along east–west- and north–south-striking walkaway lines. Then, it extracts and enhances upgoing reflection events, illuminating parts of the subsurface around and ahead of the bit. During the final step, these upgoing reflections are imaged using the inverted velocity model to reconstruct a migrated subsurface image around the well. As is the case for land surface seismic in the presence of a complex near surface, we observe a significant variation of data quality for the orthogonal receiver lines. As a result, each line provides a robust image of a different part of the subsurface. The east–west-striking line's migrated image delineates a major shallow reflector that serves as a marker for predicting the drilling depth of a deeper horizon. Likewise, migrating upgoing reflections from the north–south line accurately maps a deeper target horizon ahead of the bit. The obtained SWD images assist in setting the casing points accurately and provide a more precise ahead-of-the-bit depth for different horizons with significantly less uncertainty than surface seismic.

Data Sets

2013 ◽  
Author(s):  
James B. Elsner ◽  
Thomas H. Jagger
Keyword(s):  
Model Building ◽  
Careful Analysis ◽  
Logical Structure ◽  
Fortran Program ◽  
Data Sets ◽  
Data Set ◽  
Near Surface ◽  
Wind Speeds ◽  
The North ◽  
The One

Hurricane data originate from careful analysis of past storms by operational meteorologists. The data include estimates of the hurricane position and intensity at 6-hourly intervals. Information related to landfall time, local wind speeds, damages, and deaths, as well as cyclone size, are included. The data are archived by season. Some effort is needed to make the data useful for hurricane climate studies. In this chapter, we describe the data sets used throughout this book. We show you a work flow that includes importing, interpolating, smoothing, and adding attributes. We also show you how to create subsets of the data. Code in this chapter is more complicated and it can take longer to run. You can skip this material on first reading and continue with model building in Chapter 7. You can return here when you have an updated version of the data that includes the most recent years. Most statistical models in this book use the best-track data. Here we describe these data and provide original source material. We also explain how to smooth and interpolate them. Interpolations are needed for regional hurricane analyses. The best-track data set contains the 6-hourly center locations and intensities of all known tropical cyclones across the North Atlantic basin, including the Gulf of Mexico and Caribbean Sea. The data set is called HURDAT for HURricane DATa. It is maintained by the U.S. National Oceanic and Atmospheric Administration (NOAA) at the National Hurricane Center (NHC). Center locations are given in geographic coordinates (in tenths of degrees) and the intensities, representing the one-minute near-surface (∼10 m) wind speeds, are given in knots (1 kt = .5144 m s−1) and the minimum central pressures are given in millibars (1 mb = 1 hPa). The data are provided in 6-hourly intervals starting at 00 UTC (Universal Time Coordinate). The version of HURDAT file used here contains cyclones over the period 1851 through 2010 inclusive. Information on the history and origin of these data is found in Jarvinen et al (1984). The file has a logical structure that makes it easy to read with a FORTRAN program. Each cyclone contains a header record, a series of data records, and a trailer record.

Un diatrème phréatomagmatique montérégien dans les Appalaches du Québec

1996 ◽  
Vol 33 (5) ◽  
pp. 649-655
Author(s):  
David Morin ◽  
Michel Jébrak ◽  
Robert Marquis
Keyword(s):  
Surface Water ◽  
Country Rock ◽  
Near Surface ◽  
Metasedimentary Rocks ◽  
North East ◽  
The North ◽  
Devonian Age ◽  
Fault Network ◽  
Alkaline Lamprophyres ◽  
East West

A subcircular positive magnetic anomaly and breccias affecting a basanite and its country-rock metasedimentary rocks reveal the presence of a diatreme with a diameter of approximately 420 m, at Eastman, in the Quebec Appalachians. The post-Middle Devonian age, the position in the line of the Monteregian plutons, and the basanite composition, which is comparable to that of the Cretaceous Monteregian alkaline lamprophyres, suggest that the diatreme is related to the Monteregian magmatism. It is located at the junction of two orthogonal tectonic corridors: the north-north-east Baie Verte – Brompton line and an east−west fault network along the prolongation of the Ottawa−Bonnechère Graben. These structures are zones of weakness that probably served as a conduit for the ascending magma and near-surface water to trigger phreatomagmatic eruptions.

Random objective waveform inversion of surface waves

Geophysics ◽  
2020 ◽  
Vol 85 (4) ◽  
pp. EN49-EN61
Author(s):  
Yudi Pan ◽  
Lingli Gao
Keyword(s):  
Objective Function ◽  
Surface Waves ◽  
Waveform Inversion ◽  
Velocity Model ◽  
Initial Model ◽  
S Wave ◽  
Data Set ◽  
Near Surface ◽  
Synthetic Test ◽  
Ground Penetrating

Full-waveform inversion (FWI) of surface waves is becoming increasingly popular among shallow-seismic methods. Due to a huge amount of data and the high nonlinearity of the objective function, FWI usually requires heavy computational costs and may converge toward a local minimum. To mitigate these problems, we have reformulated FWI under a multiobjective framework and adopted a random objective waveform inversion (ROWI) method for surface-wave characterization. Three different measure functions were used, whereas the combination of one measure function with one shot independently provided one of the [Formula: see text] objective functions ([Formula: see text] is the total number of shots). We have randomly chose and optimized one objective function at each iteration. We performed a synthetic test to compare the performance of the ROWI and conventional FWI approaches, which showed that the convergence of ROWI is faster and more robust compared with conventional FWI approaches. We also applied ROWI to a field data set acquired in Rheinstetten, Germany. ROWI successfully reconstructed the main geologic feature, a refilled trench, in the final result. The comparison between the ROWI result and a migrated ground-penetrating radar profile further proved the effectiveness of ROWI in reconstructing the near-surface S-wave velocity model. We also ran the same field example by using a poor initial model. In this case, conventional FWI failed whereas ROWI still reconstructed the subsurface model to a fairly good level, which highlighted the relatively low dependency of ROWI on the initial model.

The virtual source method: Theory and case study

Geophysics ◽  
2006 ◽  
Vol 71 (4) ◽  
pp. SI139-SI150 ◽  
Author(s):  
Andrey Bakulin ◽  
Rodney Calvert
Keyword(s):  
Time Reversal ◽  
Velocity Model ◽  
Primary Energy ◽  
Physical Acoustics ◽  
Data Set ◽  
Near Surface ◽  
Complex Part ◽  
Downward Radiation ◽  
4D Seismic

We present a way to image through complex overburden. The method uses surface shots with downhole receivers placed below the most complex part of the troublesome overburden. No knowledge of the velocity model between shots and receivers is required. The method uses time-reversal logic to create a new downward-continued data set with virtual sources (VS's) at the geophone locations. Time reversal focuses energy that passes through the overburden into useful primary energy for the VS. In contrast to physical acoustics, our time reversal is done on a computer, utilizing conventional acquisition with surface shots and downhole geophones. With this approach, we can image below extremely complex (realistic) overburden — in fact, the more complex the better. We recast the data to those with sources where we actually know and can control the waveform that has a downward-radiation pattern that may also be controlled, and is reproducible for 4D even if the near-surface changes or the shooting geometry is altered slightly. To illustrate the method, we apply the VS technique to a synthetic, elastic example with extreme heterogeneity, where conventional approaches fail to image the data. A 4D field-data example shows that the VS method (VSM) enables sensitive reservoir monitoring below a complex, time-variant near surface that is not achievable with surface 4D seismic or conventional 4D vertical seismic profiling (VSP).

scholarly journals Thermally driven circulation in a region of complex topography: comparison of wind-profiling radar measurements and MM5 numerical predictions

2006 ◽  
Vol 24 (6) ◽  
pp. 1537-1549 ◽  
Author(s):  
L. Bianco ◽  
B. Tomassetti ◽  
E. Coppola ◽  
A. Fracassi ◽  
M. Verdecchia ◽  
...  
Keyword(s):  
Land Surface ◽  
Central Italy ◽  
Surface Wind ◽  
Lower Atmosphere ◽  
Complex Topography ◽  
Model Errors ◽  
Data Set ◽  
Near Surface ◽  
Numerical Predictions ◽  
Thermally Driven

Abstract. The diurnal variation of regional wind patterns in the complex terrain of Central Italy was investigated for summer fair-weather conditions and winter time periods using a radar wind profiler. The profiler is located on a site where interaction between the complex topography and land-surface produces a variety of thermally and dynamically driven wind systems. The observational data set, collected for a period of one year, was used first to describe the diurnal evolution of thermal driven winds, second to validate the Mesoscale Model 5 (MM5) that is a three-dimensional numerical model. This type of analysis was focused on the near-surface wind observation, since thermally driven winds occur in the lower atmosphere. According to the valley wind theory expectations, the site – located on the left sidewall of the valley (looking up valley) – experiences a clockwise turning with time. Same characteristics in the behavior were established in both the experimental and numerical results. Because the thermally driven flows can have some depth and may be influenced mainly by model errors, as a third step the analysis focuses on a subset of cases to explore four different MM5 Planetary Boundary Layer (PBL) parameterizations. The reason is to test how the results are sensitive to the selected PBL parameterization, and to identify the better parameterization if it is possible. For this purpose we analysed the MM5 output for the whole PBL levels. The chosen PBL parameterizations are: 1) Gayno-Seaman; 2) Medium-Range Forecast; 3) Mellor-Yamada scheme as used in the ETA model; and 4) Blackadar.

Revitalizing seismic data with new imaging solutions to positively impact field development

2019 ◽  
Vol 38 (1) ◽  
pp. 20-26
Author(s):  
Gareth Venfield ◽  
Michael Townsend ◽  
Paul Cattermole ◽  
Tony Martin ◽  
Stuart Fairhead
Keyword(s):  
Seismic Data ◽  
Model Building ◽  
Large Population ◽  
Waveform Inversion ◽  
Structural Complexity ◽  
Velocity Model ◽  
Near Surface ◽  
Field Development ◽  
The North ◽  
The Right

Evaluating, planning, and forecasting are integral parts of asset development and continue throughout the life cycle of a producing field. The right decisions are required to lower risk and maximize economic recovery in challenging environments. The Claymore Complex is located in the North Sea and was discovered in 1977. A number of geologic challenges affect the imaging and hence field development including a system of shallow interweaving Quaternary channels, numerous high-contrast layers of varying composition, overburden structural complexity, and a sequence of tilted fault blocks containing the main reservoir systems. Historically, seismic processing over the area has not fully solved these challenges, resulting in significant imaging uncertainty. The Claymore Complex has an abundance of data including a large population of well information and interpretation. As part of a data revitalization process, geostatistical integration of these auxiliary data into a velocity model building sequence using full-waveform inversion and wavelet shift tomography enabled the generation of an accurate high-resolution velocity model. Access to a recent 3D survey acquired obliquely to existing data improved subsurface illumination for both the model building and imaging phases. Near-surface imaging effects and their impact on reservoir positioning and clarity were improved using the upgraded velocity model and dual-azimuth data. Shallow imaging challenges were mitigated by utilizing the additional illumination and angular diversity contained within the multiple reverberations. The revitalization of the Claymore area seismic data has challenged the current understanding of the geologic framework. Confidence has been improved by solving depth conversion problems and increasing the understanding of fault positioning and reservoir connectivity, which are invaluable for future field development.

Holocene Mg/Ca, alkenones, and light stable isotope measurements on the outer North Iceland shelf (MD99-2269): A comparison with other multi-proxy data and sub-division of the Holocene

The Holocene ◽  
2016 ◽  
Vol 27 (1) ◽  
pp. 52-62 ◽  
Author(s):  
Greta B Kristjánsdóttir ◽  
Matthias Moros ◽  
John T Andrews ◽  
Anne E Jennings
Keyword(s):  
Bottom Water ◽  
Environmental Changes ◽  
Singular Spectrum Analysis ◽  
Principal Component ◽  
Sea Ice Extent ◽  
Data Set ◽  
Bottom Water Temperature ◽  
Near Surface ◽  
The Holocene ◽  
The North

To evaluate whether proxies that record surface, near-surface, and bottom water conditions from the North Iceland shelf have similar trends and periodicities, we examine Holocene century-scale paleoceanographic records from core MD99-2269. This core site lies close to the boundary between Atlantic and Arctic/Polar waters, and in an area frequently influenced by drift ice. The proxies are stable δ13C and δ18O values on planktonic and benthic foraminifera, alkenone-based sea-surface temperatures (SST°C), and foraminiferal Mg/Ca SST°C and bottom water temperature (BWT°C) estimates. These data were converted to equi-spaced 60-year time-series; significant trends were extracted using Singular Spectrum Analysis, which accounted for between 50% and 70% of the variance. In order to evaluate within-site ocean climate variability, a comparison between these data and previously published proxies from MD99-2269 was carried out on a standardized data set of 14 proxies covering the interval 400–9200 cal. yr BP. Principal component (PC) analysis indicated that the first two PC axes accounted for 57% of the variability with high loadings primarily defining ‘nutrient’ and ‘temperature’ proxies. Fuzzy k-mean clustering of the 14 climate proxies indicated major environmental changes at ~6350 and ~3450 cal. yr BP, which define local early-, middle-, and late-Holocene climatic shifts. Our results indicate that the major control on the combined proxy signal is the Holocene decrease in June insolation, but regional changes in such factors as sea-ice extent and salinity are required to explain the threefold division of the Holocene.

scholarly journals COSMOS-UK: National soil moisture and hydrometeorology data for empowering UK environmental science

2020 ◽  
Author(s):  
Hollie M. Cooper ◽  
Emma Bennett ◽  
James Blake ◽  
Eleanor Blyth ◽  
David Boorman ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Real Time ◽  
Land Surface ◽  
Large Scale ◽  
Environmental Science ◽  
Cosmic Ray ◽  
Fast Neutrons ◽  
High Temporal Resolution ◽  
Field Scale ◽  
Near Surface

Abstract. The COSMOS-UK observation network has been providing field scale soil moisture and hydrometeorological measurements across the UK since 2013. At the time of publication a total of 51 COSMOS-UK sites have been established, each delivering high temporal resolution data in near-real time. Each site utilises a cosmic-ray neutron sensor, which counts fast neutrons at the land surface. These measurements are used to derive field scale near-surface soil water content, which can provide unique insight for science, industry, and agriculture by filling a scale gap between localised point soil moisture and large-scale satellite soil moisture datasets. Additional soil physics and meteorological measurements are made by the COSMOS-UK network including precipitation, air temperature, relative humidity, barometric pressure, soil heat flux, wind speed and direction, and components of incoming and outgoing radiation. These near-real time observational data can be used to improve the performance of hydrological models, validate remote sensing products, improve hydro-meteorological forecasting and underpin applications across a range of other scientific fields. The most recent version of the COSMOS-UK dataset is publically available at https://doi.org/10.5285/37702a54-b7a4-40ff-b62e-d14b161b69ca (Stanley et al., 2020).

scholarly journals Summer diatom blooms in the eastern North Pacific gyre investigated with a long-endurance autonomous surface vehicle

2018 ◽  
Author(s):  
Emily E Anderson ◽  
Cara Wilson ◽  
Anthony H Knap ◽  
Tracy A Villareal
Keyword(s):  
Real Time ◽  
North Pacific ◽  
Autonomous Vehicle ◽  
Nitrogen Fixing ◽  
North Pacific Subtropical Gyre ◽  
Limited Region ◽  
Near Surface ◽  
The North ◽  
Autonomous Surface Vehicle ◽  
Diatom Blooms

Satellite chlorophyll (chl) observations have repeatedly observed summertime phytoplankton blooms in the North Pacific subtropical gyre (NPSG), a region of open ocean that is far removed from any land-derived or Ekman upwelling nutrient sources. These blooms are dominated by N2-fixing diatom-cyanobacteria associations of the diatom genera Rhizosolenia Brightwell and Hemiaulus Ehrenberg. Their nitrogen fixing endosymbiont, Richelia intracellularis J.A. Schmidt, is hypothesized to be critical to the development of blooms in this nitrogen limited region. However, due to the remote location and unpredictable duration of the summer blooms, prolonged in situ observations are rare outside of the Station ALOHA time-series off of Hawai’i. In summer, 2015, a proof-of–concept mission using the autonomous vehicle, Honey Badger (Wave Glider SV2), collected near-surface (<20m) observations in the NPSG using hydrographic, meteorological, optical, and imaging sensors designed to focus on phytoplankton abundance, distribution and physiology of this bloom-forming region. Hemiaulus and Rhizosolenia cell abundance was determined using digital holography for the entire June-November mission. Honey Badger was not able to reach the 30°N subtropical front region where most of the satellite chl blooms have been observed, but near-real time navigational control allowed it to transect two blooms near 25°N. The two taxa did not co-occur in large numbers, rather the blooms were dominated by either Hemiaulus or Rhizosolenia. The 2-4 August 2015 bloom was comprised of 96% Hemiaulus and the second bloom, 15-17 August 2015, was dominated by Rhizosolenia (75%). The holograms also imaged undisturbed, fragile Hemiaulus aggregates throughout the sampled area at ~10 L-1. Aggregated Hemiaulus represented the entire observed population at times and had a widespread distribution independent of the SEP. Aggregate occurrence was not consistent with a density dependent formation mechanism and may represent a natural growth form in undisturbed conditions. The photosynthetic potential index (Fv:Fm) increased from ~0.4 to ~0.6 during both blooms indicating a physiologically robust phytoplankton community in the blooms. The diel pattern of Fv:Fm(nocturnal maximum; diurnal minimum) was consistent with macronutrient limitation throughout the mission with no evidence of Fe-limitation despite the presence of nitrogen fixing diatom-diazotroph assemblages. During the 5-month mission, Honey Badger covered ~5690 km (3070 nautical miles), acquired 9336 holograms, and reliably transmitted data onshore in near real-time. Software issues developed with the active fluorescence sensor that terminated measurements in early September. Although images were still useful at the end of the mission, fouling of the LISST-Holo optics was considerable, and appeared to be the most significant issue facing deployments of this duration.

scholarly journals Near‐surface seismic properties for elastic wavefield decomposition: Estimates based on multicomponent land and seabed recordings

Geophysics ◽  
2003 ◽  
Vol 68 (6) ◽  
pp. 2073-2081 ◽  
Author(s):  
Remco Muijs ◽  
O. A. Johan Robertsson ◽  
Andrew Curtis ◽  
Klaus Holliger
Keyword(s):  
Material Properties ◽  
S Wave ◽  
Data Set ◽  
Near Surface ◽  
Seismic Properties ◽  
Wave Velocities ◽  
The North ◽  
Orthogonal Components ◽  
Multicomponent Data ◽  
Wavefield Decomposition

Accurate knowledge of the seismic material properties in the immediate vicinity of the receivers represents a prerequisite for elastic wavefield decomposition. We present strategies for estimating the elastic material properties for both land and seabed multicomponent seismic data. The proposed scheme for land data requires dense multicomponent geophone configurations, which allow spatial wavefield derivatives to be explicitly calculated. The required information can be obtained with four three‐component surface geophones positioned at the corners of a square, and a fifth geophone buried at a shallow depth below the center of the square. The technique yields local estimates of the near‐surface P‐ and S‐wave velocities, but the density cannot be constrained. Using a similar approach for four‐component (three orthogonal components of particle velocity plus pressure) seabed recordings allows the P‐ and S‐wave velocities as well as the density of the seafloor to be estimated. In this case, the proposed scheme does not require buried geophones, and it is applicable to multicomponent data recorded in routine seabed surveys. Compared to existing techniques, the new method allows the elastic sea‐floor properties to be more accurately determined, and it does not rely critically on the inclusion of large‐offset data. Numerical tests indicate that the proposed schemes are robust and yield accurate results, provided that the signal used for the inversion contains sufficient horizontal energy and can be clearly identified and separated from other signals. Although the schemes are designed for application on the first arrivals, they are, in principle, applicable to any data window containing isolated P‐ or S‐arrivals. The proposed scheme is successfully applied to a seabed data set acquired in the North Sea. In contrast, the application on a multicomponent land data set was unsuccessful, because of strong receiver‐to‐receiver variations in amplitude and phase, probably caused by differences in coupling and instrument response.

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