A direct noise attenuation approach in processing of land continuous records

2021 ◽  
Vol 40 (4) ◽  
pp. 288-296
Author(s):  
Chengbo Li ◽  
Charles C. Mosher ◽  
Yu Zhang
Keyword(s):  
Noise Suppression ◽  
Noise Attenuation ◽  
Multiple Sources ◽  
Permian Basin ◽  
Fixed Length ◽  
The North ◽  
Excitation Time ◽  
North Slope Of Alaska ◽  
Source Excitation ◽  
Incoherent Noise

Blended source acquisition has drawn great attention in industry due to its increased efficiency and reduced overall cost for acquiring seismic data. It eliminates the requirement of a minimum time (usually determined by record length) between adjacent shots and allows multiple sources to be activated simultaneously and independently. Conventional processing simply converts continuous records into fixed-length records using the source excitation time and then applies traditional denoising techniques to the fixed-length records. Source excitation time is used to extract fixed-length records that are the equivalent of traditional synchronous recording. Here, we elaborate on the usage of continuous records for land noise attenuation. Compared to conventional common shot/receiver/midpoint/offset domains, continuous records represent the data in the naturally recorded domain. This domain offers flexible and much longer record lengths to work with and, moreover, enables exploiting the characteristics of noise prior to correlation, shot slicing, or other preprocessing. We limit our discussions to the techniques and methods for attenuating coherent environmental and source-generated noise on vibroseis data. We have found that incoherent noise can be handled effectively by traditional noise suppression methods after deblending. We illustrate the effectiveness of noise attenuation in the continuously recorded domain for three different types of noise using field examples from the North Slope of Alaska and the Permian Basin.

An application for removing cultural noise from aeromagnetic data

Geophysics ◽  
2001 ◽  
Vol 66 (1) ◽  
pp. 213-219 ◽  
Author(s):  
Stefan Muszala ◽  
Paul L. Stoffa ◽  
L. A. Lawver
Keyword(s):  
Noise Suppression ◽  
Aeromagnetic Data ◽  
Aeromagnetic Survey ◽  
University Of Texas ◽  
Cultural Objects ◽  
The North ◽  
Automated Method ◽  
North Slope Of Alaska ◽  
The Many ◽  
Cultural Noise

A high‐resolution aeromagnetic survey collected over the North Slope of Alaska by World Geoscience was acquired in response to a need for highly detailed data in an area where traditional geophysical techniques are expensive and prohibitive (McConnell, 1995) (Figure 1). These data were recently released to the University of Texas’ Institute for Geophysics and provide a unique opportunity to investigate the problem of cultural noise suppression in aeromagnetic data. The data contain isolated magnetic anomalies that are presumably from the many drill platforms and their accompanying cultural objects such as buildings and pipe repositories (Figure 2). We present a new, automated method to reduce the amplitude of these cultural anomalies without affecting the magnetic signal from the surrounding geology.

Dispersive noise removal in t-x space: Application to Arctic data

Geophysics ◽  
1988 ◽  
Vol 53 (3) ◽  
pp. 346-358 ◽  
Author(s):  
Greg Beresford‐Smith ◽  
Rolf N. Rango
Keyword(s):  
Signal To Noise Ratio ◽  
Noise Analysis ◽  
Noise Removal ◽  
North Slope ◽  
Frequency Bandwidth ◽  
The North ◽  
North Slope Of Alaska ◽  
Seismic Records ◽  
Time Offset ◽  
Undersampled Data

Strongly dispersive noise from surface waves can be attenuated on seismic records by Flexfil, a new prestack process which uses wavelet spreading rather than velocity as the criterion for noise discrimination. The process comprises three steps: trace‐by‐trace compression to collapse the noise to a narrow fan in time‐offset (t-x) space; muting of the noise in this narrow fan; and inverse compression to recompress the reflection signals. The process will work on spatially undersampled data. The compression is accomplished by a frequency‐domain, linear operator which is independent of trace offset. This operator is the basis of a robust method of dispersion estimation. A flexural ice wave occurs on data recorded on floating ice in the near offshore of the North Slope of Alaska. It is both highly dispersed and of broad frequency bandwidth. Application of Flexfil to these data can increase the signal‐to‐noise ratio up to 20 dB. A noise analysis obtained from a microspread record is ideal to use for dispersion estimation. Production seismic records can also be used for dispersion estimation, with less accurate results. The method applied to field data examples from Alaska demonstrates significant improvement in data quality, especially in the shallow section.

InSAR measurements of surface deformation over permafrost on the North Slope of Alaska

2010 ◽  
Vol 115 (F3) ◽  
Author(s):  
Lin Liu ◽  
Tingjun Zhang ◽  
John Wahr
Keyword(s):  
Surface Deformation ◽  
North Slope ◽  
The North ◽  
North Slope Of Alaska

Cloud Properties over the North Slope of Alaska: Identifying the Prevailing Meteorological Regimes

2012 ◽  
Vol 25 (23) ◽  
pp. 8238-8258 ◽  
Author(s):  
Johannes Mülmenstädt ◽  
Dan Lubin ◽  
Lynn M. Russell ◽  
Andrew M. Vogelmann
Keyword(s):  
Time Series ◽  
Climate Model ◽  
North Slope ◽  
Test Cases ◽  
Synoptic Scale ◽  
Long Time Series ◽  
The North ◽  
Cloud Properties ◽  
North Slope Of Alaska ◽  
Long Time

Abstract Long time series of Arctic atmospheric measurements are assembled into meteorological categories that can serve as test cases for climate model evaluation. The meteorological categories are established by applying an objective k-means clustering algorithm to 11 years of standard surface-meteorological observations collected from 1 January 2000 to 31 December 2010 at the North Slope of Alaska (NSA) site of the U.S. Department of Energy Atmospheric Radiation Measurement Program (ARM). Four meteorological categories emerge. These meteorological categories constitute the first classification by meteorological regime of a long time series of Arctic meteorological conditions. The synoptic-scale patterns associated with each category, which include well-known synoptic features such as the Aleutian low and Beaufort Sea high, are used to explain the conditions at the NSA site. Cloud properties, which are not used as inputs to the k-means clustering, are found to differ significantly between the regimes and are also well explained by the synoptic-scale influences in each regime. Since the data available at the ARM NSA site include a wealth of cloud observations, this classification is well suited for model–observation comparison studies. Each category comprises an ensemble of test cases covering a representative range in variables describing atmospheric structure, moisture content, and cloud properties. This classification is offered as a complement to standard case-study evaluation of climate model parameterizations, in which models are compared against limited realizations of the Earth–atmosphere system (e.g., from detailed aircraft measurements).

MS prevalence in New Zealand, an ethnically and latitudinally diverse country

2010 ◽  
Vol 16 (12) ◽  
pp. 1422-1431 ◽  
Author(s):  
Bruce V Taylor ◽  
John F Pearson ◽  
Glynnis Clarke ◽  
Deborah F Mason ◽  
David A Abernethy ◽  
...  
Keyword(s):  
New Zealand ◽  
Environmental Factors ◽  
Latitudinal Gradient ◽  
Population Level ◽  
Cross Sectional Study ◽  
European Population ◽  
Multiple Sources ◽  
Cross Sectional ◽  
The North ◽  
Mcdonald Criteria

Background: The prevalence of multiple sclerosis (MS) is not uniform, with a latitudinal gradient of prevalence present in most studies. Understanding the drivers of this gradient may allow a better understanding of the environmental factors involved in MS pathogenesis. Method: The New Zealand national MS prevalence study (NZMSPS) is a cross-sectional study of people with definite MS (DMS) (McDonald criteria 2005) resident in New Zealand on census night, 7 March 2006, utilizing multiple sources of notification. Capture—recapture analysis (CRA) was used to estimate missing cases. Results: Of 2917 people with DMS identified, the crude prevalence was 72.4 per 100,000 population, and 73.1 per 100,000 when age-standardized to the European population. CRA estimated that 96.7% of cases were identified. A latitudinal gradient was seen with MS prevalence increasing three-fold from the North (35°S) to the South (48°S). The gradient was non-uniform; females with relapsing—remitting/secondary-progressive (RRMS/SPMS) disease have a gradient 11 times greater than males with primary-progressive MS ( p < 1 × 10-7). DMS was significantly less common among those of Māori ethnicity. Conclusions: This study confirms the presence of a robust latitudinal gradient of MS prevalence in New Zealand. This gradient is largely driven by European females with the RRMS/SPMS phenotype. These results indicate that the environmental factors that underlie the latitudinal gradient act differentially by gender, ethnicity and MS phenotype. A better understanding of these factors may allow more targeted MS therapies aimed at modifiable environmental triggers at the population level.

scholarly journals Ice processes and growth history on Arctic and sub-Arctic lakes using ERS-1 SAR data

Polar Record ◽  
1995 ◽  
Vol 31 (177) ◽  
pp. 115-128 ◽  
Author(s):  
K. Morris ◽  
M. O. Jeffries ◽  
W. F. Weeks
Keyword(s):  
Arctic Lakes ◽  
Polar Regions ◽  
Lake Ice ◽  
Sar Images ◽  
The North ◽  
Growth History ◽  
North Slope Of Alaska ◽  
Term Monitoring ◽  
Selection Of

AbstractA survey of ice growth and decay processes on a selection of shallow and deep sub-Arctic and Arctic lakes was conducted using radiometrically calibrated ERS-1 SAR images. Time series of radar backscatter data were compiled for selected sites on the lakes during the period of ice cover (September to June) for the years 1991–92 and 1992–93. A variety of lake-ice processes could be observed, and significant changes in backscatter occurred from the time of initial ice formation in autumn until the onset of the spring thaw. Backscatter also varied according to the location and depth of the lakes. The spatial and temporal changes in backscatter were most constant and predictable at the shallow lakes on the North Slope of Alaska. As a consequence, they represent the most promising sites for long-term monitoring and the detection of changes related to global warming and its effects on the polar regions.

Underbalanced Drilling with Coiled Tubing: A Case Study on the Alaskan North Slope, Which Proves the Benefits of Drilling a Straight Hole

2021 ◽  
Author(s):  
Antoni Miszewski ◽  
Adam Miszewski ◽  
Richard Stevens ◽  
Matteo Gemignani
Keyword(s):  
Relative Effectiveness ◽  
Shallow Depth ◽  
North Slope ◽  
Coiled Tubing ◽  
The North ◽  
North Slope Of Alaska ◽  
Minimum Requirements ◽  
Bottom Hole Assembly ◽  
Alaskan North Slope ◽  
Future Work

Abstract A set of 5 wells were to be drilled with directional Coiled Tubing Drilling (CTD) on the North Slope of Alaska. The particular challenges of these wells were the fact that the desired laterals were targeted to be at least 6000ft long, at a shallow depth. Almost twice the length of laterals that are regularly drilled at deeper depths. The shallow depth meant that 2 of the 5 wells involved a casing exit through 3 casings which had never been attempted before. After drilling, the wells were completed with a slotted liner, run on coiled tubing. This required a very smooth and straight wellbore so that the liner could be run as far as the lateral had been drilled. Various methods were considered to increase lateral reach, including, running an extended reach tool, using friction reducer, increasing the coiled tubing size and using a drilling Bottom Hole Assembly (BHA) that could drill a very straight well path. All of these options were modelled with tubing forces software, and their relative effectiveness was evaluated. The drilling field results easily exceeded the minimum requirements for success. This project demonstrated record breaking lateral lengths, a record length of liner run on coiled tubing in a single run, and a triple casing exit. The data gained from this project can be used to fine-tune the modelling for future work of a similar nature.

Changes in tall shrub abundance on the North Slope of Alaska, 2000–2010

2018 ◽  
Vol 219 ◽  
pp. 221-232 ◽  
Author(s):  
Rocio R. Duchesne ◽  
Mark J. Chopping ◽  
Ken D. Tape ◽  
Zhuosen Wang ◽  
Crystal L.B. Schaaf
Keyword(s):  
North Slope ◽  
The North ◽  
North Slope Of Alaska ◽  
Tall Shrub

Depositional facies, diagenetic clay minerals and reservoir quality of Rotliegend sediments in the Southern Permian Basin (North Sea): a review

Clay Minerals ◽  
1982 ◽  
Vol 17 (1) ◽  
pp. 55-67 ◽  
Author(s):  
U. Seemann
Keyword(s):  
Clay Minerals ◽  
North Sea ◽  
Effective Porosity ◽  
Hydrocarbon Exploration ◽  
Reservoir Quality ◽  
Burial Diagenesis ◽  
Permian Basin ◽  
Northern Margin ◽  
The North

AbstractThe Southern Permian Basin of the North Sea represents an elongate E-W oriented depo-centre along the northern margin of the Variscan Mountains. During Rotliegend times, three roughly parallel facies belts of a Permian desert developed, these following the outline of the Variscan Mountains. These belts were, from south to north, the wadi facies, the dune and interdune facies, and the sabkha and desert lake facies. The bulk of the gas reservoirs of the Rotliegend occur in the aeolian dune sands. Their recognition, and the study of their geometry, is therefore important in hydrocarbon exploration. Equally important is the understanding of diagenesis, particularly of the diageneticaily-formed clay minerals, because they have an important influence on the reservoir quality of these sands. Clay minerals were introduced to the aeolian sands during or shortly after their deposition in the form of air-borne dust, which later formed thin clay films around the grains. During burial diagenesis, these clay films may have acted as crystallization nuclei for new clay minerals or for the transformation of existing ones. Depending on their crystallographic habit, the clay minerals can seriously affect the effective porosity and permeability of the sands.

Effects of Climate on the Active Layer and Permafrost on the North Slope of Alaska, U.S.A.

1997 ◽  
Vol 8 (1) ◽  
pp. 45-67 ◽  
Author(s):  
T. Zhang ◽  
T. E. Osterkamp ◽  
K. Stamnes
Keyword(s):  
Active Layer ◽  
North Slope ◽  
The North ◽  
North Slope Of Alaska
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