This document presents the results of a study analyzing Late Triassic channel systems in the Loppa High region of the southwestern Barents Sea using 3D seismic data. The author interprets nine channel systems within the Upper Snadd Formation between depths of -1088ms to -1152ms. Three channel grids are examined in detail and show evidence of successive channel migration and preservation of channel-belt deposits. Criteria for distinguishing between mud-filled and sand-filled channel types are presented based on seismic amplitude, reflectivity, shape, and sedimentary features.

1. Late Triassic channel systems of the Loppa High, SW Barents Sea
UIT
The Arctic University of Norway,
Faculty of science and technology
Department of Geology
29 January 2016
Tromsø, Norway
Master thesis in
GEO-3900
Student - Agafonova Olga
Supervisor – Stefan Buenz

2. 1. Introduction
1.1 Objectives
1.2 Background (brief introduction to channels)
2. Regional geology
3. Dataset and methodology
4. Results & discussion
4.1 Seismic stratigraphy
4.2 Controls over sediment distribution and deposition
4.3 Interpretation of channel systems
4.3.1 Channel Grid #1
4.3.2 Channel Grid #2
4.3.3 Channel Grid #3
4.3.4 Criteria for distinguishing between mud- and sand-filled channels
4.3.5 Channel dimensions
Late Triassic channel systems at the Loppa High, SW Barents Sea
Agafonova Olga
Page 2
Content

3. Late Triassic channel systems at the Loppa High, SW Barents Sea
Agafonova Olga
Page 3
Content
1. Introduction
1.1 Objectives
1.2 Background (brief introduction to channels)
2. Regional geology
3. Dataset and methodology
4. Results & discussion
4.1 Seismic stratigraphy
4.2 Controls over sediment distribution and deposition
4.3 Interpretation of channel systems
4.3.1 Channel Grid #1
4.3.2 Channel Grid #2
4.3.3 Channel Grid #3
4.3.4 Criteria for distinguishing between mud- and sand-filled channels
4.3.5 Channel dimensions

4. Late Triassic channel systems at the Loppa High, SW Barents Sea
Agafonova Olga
 To reveal the presents and distribution of fluvial paleo-channels of Late Triassic interval
 To visualize, describe and improve an understanding of ancient paleo-channel systems
 To provide a basis sedimentology insight into development of channel sandstone bodies of the
Snadd formation
Objectives
Page 4

5. Background
Late Triassic channel systems at the Loppa High, SW Barents Sea
Agafonova Olga
Meandering fluvial system
• Single channel thread
• Follows a sinuous path
• Erosion on outer bank
• Deposition on inner bank
• Development of meander
loops
Braided fluvial system
• High stream power
• High rates of erosion and
deposition
• Coarse-grained channel-fill
Anastomosed fluvial system
• Laterally stable
• Low gradient
• Highly sinuous
Laterally accreted deposits
Page 5
Lenticular storeys
geometry with fining
upwards succession

6. Late Triassic channel systems at the Loppa High, SW Barents Sea
Agafonova Olga
Page 6
Content
1. Introduction
1.1 Objectives
1.2 Background (brief introduction to channels)
2. Regional geology
3. Dataset and methodology
4. Results & discussion
4.1 Seismic stratigraphy
4.2 Controls over sediment distribution and deposition
4.3 Interpretation of channel systems
4.3.1 Channel Grid #1
4.3.2 Channel Grid #2
4.3.3 Channel Grid #3
4.3.4 Criteria for distinguishing between mud- and sand-filled channels
4.3.5 Channel dimensions

7. Regional geology
Late Triassic channel systems at the Loppa High, SW Barents Sea
Agafonova Olga
Location of the Barents Sea and approximate
location of Loppa High
A’
A
Dataset
Modified from Evy Glostard-Clarc.
succession
Structural elements of the western Barents Sea.
Location of 3D seismic dataset (LN09M01)
Regional seismic cross- section from NW to SE of the Western Barents Sea
A northwest to southeast seismic line towards paleo-Loppa High
Loppa High
S5 - Upper Snadd (Late Triassic)
S4 - Lower Snadd (Middle Triassic)
The study area
Page 7

8. Stratigraphy & Tectonic evolution
Late Triassic channel systems at the Loppa High, SW Barents Sea
Agafonova Olga
Chronostratigraphic chart of the study area
Study
area
Siltstone Sandstone Evaporate
Uplift and
erosion
Uplift and
erosion
Uplift and
glacial
erosion
Early Triassic
Middle Triassic
Late Triassic
General shallowing depositional
environment of Triassic
Page 8

9. Late Triassic channel systems at the Loppa High, SW Barents Sea
Agafonova Olga
Page 9
Content
1. Introduction
1.1 Objectives
1.2 Background (brief introduction to channels)
2. Regional geology
3. Dataset and methodology
4. Results & discussion
4.1 Seismic stratigraphy
4.2 Controls over sediment distribution and deposition
4.3 Interpretation of channel systems
4.3.1 Channel Grid #1
4.3.2 Channel Grid #2
4.3.3 Channel Grid #3
4.3.4 Criteria for distinguishing between mud- and sand-filled channels
4.3.5 Channel dimensions

10. Late Triassic channel systems at the Loppa High, SW Barents Sea
Agafonova Olga
The study area 3D survey LN09M0
3D original and cropped seismic cubes The frequency spectra of the seismic volume (LN0901)
Availability of exploratory well data
15 HZ 65 HZ
34 HZ
Seismic data
•Flat top
•Broad frequency
spectrum of 15-65 Hz
•Peak frequency 34 HZ
Page 10
Dataset

11. Methodology
Generation of time-to-depth relationship
Seismic interpretation
(horizons correlation)
Seismic multi-attributes generation Spectral decomposition Geobody extractionAdvanced visualization methods
7120/1-1
Late Triassic channel systems at the Loppa High, SW Barents Sea
Agafonova Olga
Page 11
Complex interpretation
Interpretation
Delineation
Visualization
The adopted
methodology

12. Late Triassic channel systems at the Loppa High, SW Barents Sea
Agafonova Olga
Page 12
Content
1. Introduction
1.1 Objectives
1.2 Background (brief introduction to channels)
2. Regional geology
3. Dataset and methodology
4. Results & discussion
4.1 Seismic stratigraphy
4.2 Controls over sediment distribution and deposition
4.3 Interpretation of channel systems
4.3.1 Channel Grid #1
4.3.2 Channel Grid #2
4.3.3 Channel Grid #3
4.3.4 Criteria for distinguishing between mud- and sand-filled channels
4.3.5 Channel dimensions

13. Results – Seismic stratigraphy
Late Triassic channel systems at the Loppa High, SW Barents Sea
Agafonova Olga
Time-thickness map, showing
westward-thickening of S5
upper Snadd
Seismic cross-section showing upper Snadd sequence (S5)
Paleogeographic map in parts of Snadd
Fm, showing paleo-environments during
Late Triassic
S5 Upper Snadd
Deltaic (Upper Snadd)
Shallow-shelf (Lower Snadd)
MFS
Distribution of sediments
Page 13
Directions of the main
sediment transport

14. Results - Interpretation of channel systems
Late Triassic channel systems at the Loppa High, SW Barents Sea
Agafonova Olga
Interpreted seismic section through the 3D seismic dataset
Snadd Fm
Schematic diagram
relative to time-lines of
Triassic Formations
Geobodies of nine observed
channel system extracted from
-1088 ms to -1152 ms interval of
the Upper Snadd Formation
Triassic
Snadd Fm
S5
S4
Page 14

15. Results - Controls over sediment distribution and deposition
Late Triassic channel systems at the Loppa High, SW Barents Sea
Agafonova Olga
Expected thickness profile of a
channelized body
maximum thickness,
sediment sorting
Longitudinal profile of channel Grid 1
coarser sediment accumulation
on the outside deeper part of the
channel bends
Page 15

16. Results – Grid #1
Late Triassic channel systems at the Loppa High, SW Barents Sea
Agafonova Olga
RGB-Envelope-SO Semblance opacity blend
Most negative curvature
attribute
Combined most negative and most positive
curvature attributeVariance time-slice
Seismic amplitude
signature
Instantaneous frequency
Spectral decomposition
Channel belt deposits:
•homogeneous
•well-sorted
•sandstones
•mud-rich levees
•vertical U-shaped
reflectors package
•Incised
•flanked by levees
Page 16

17. Results
Late Triassic channel systems at the Loppa High, SW Barents Sea
Agafonova Olga
Chanel Grid 1
Migrating channel segment
leading to accretion and
preservation of channel-belt
deposits
Spatial distribution of coarse-grained channel-belt deposits
Successive migration
of the river channel
Grid 1
Page 17

18. Late Triassic channel systems at the Loppa High, SW Barents Sea
Agafonova Olga
Results – Channel #2
Variance attribute time-slice
Time-slice through most
positive curvature attribute
Stratal slice through combined
most negative and most positive
curvature attributes
Seismic amplitude signature
RMS, Envelope and Gradient Magnitude show strong ribbon–like amplitude anomaly
Channel belt deposits:
•homogeneous
•well-sorted
•sandstones
•mud-rich levees
•High amplitude V-shaped
reflectors package
•Incised
•Flanked by levees
Page 18

19. Results
Late Triassic channel systems at the Loppa High, SW Barents Sea
Agafonova Olga
Chanel Grid 2
Channel migration leading to preservation of
channel-belt deposits
Shape and connectivity
of deposits
Successive
migration of
the river
channel Grid 2
Page 19

20. Results – Channel #3
Late Triassic channel systems at the Loppa High, SW Barents Sea
Agafonova Olga
instantaneous
frequency attribute
Standard frequency
decomposition RGB
Combines most positive and most negative curvature attributeVariance attribute
Seismic amplitude signature
Page 20
Channel belt deposits:
•mud-filled
•sand-prone levees

21. Results
Late Triassic channel systems at the Loppa High, SW Barents Sea
Agafonova Olga
Chanel Grid 3
Spatial distribution of
coarse-grained channel-
belt deposits
Channel migration leading to preservation of channel-belt deposits
Shape and connectivity
of channel- belt deposits
Successive migration of the
river channel Grid 3
Page 21

22. Results - Criteria for distinguishing between mud- and sand-filled channels
Late Triassic channel systems at the Loppa High, SW Barents Sea
Agafonova Olga
Page 22
Sand-filled channel type 1
Low to moderate amplitude
Moderate reflectivity
Weakly-laterally confined reflection (red rectangle)
Shape: wide, flat or locally wavy base
Moderate sinuosity
Variable width
Development of localized meander scrolls, sandy
basal-lag and sandy point bars
Sand-filled channel type 2
Moderate to high amplitude
Moderate to high reflectivity
Well-laterally confined reflection (red rectangle)
Shape: narrow. mounded base
Moderate sinuosity
Variable width in Variance and SO Semblance
Development of minor isolated basal-lag sand
bodies
Mud filled channel.
Low to moderate amplitude
Moderate reflectivity
Laterally confined reflection (red rectangle)
Shape; flat, locally wavy base, wider
Moderate sinuosity
Apparent constant width in Variance and SO
Semblance
Development of minor point bars and shale baffles
Based on the information:
•Seismic attributes
•Geomorphology
•Internal seismic architecture

23. Results - Channel dimensions
Late Triassic channel systems at the Loppa High, SW Barents Sea
Agafonova Olga
Earliest channel evolution
stage
Latest channel evolution
stage
Planform geometries
*Sinuosity indicates the degree of meandering and channel migration.
Page 23
•Continuing channel migration
•Enlargement of meander bend amplitude
•Increased sinuosity
Classification of rivers sinuosity, after (Rosgen, 2007), based on the
morphological characteristics of river channels.

24. Conclusions
Late Triassic channel systems at the Loppa High, SW Barents Sea
Agafonova Olga
Page 24
An interval of fluvial channel bodies is defined within upper (S5) part of the Snadd
formation
The fluvial channel migration leads to accretion and preservation of point bar and
concave-bank deposits within fluvial channel belts and affects their geometry and shape
Migration of river channel control the geometry of and orientation of channel-belt
deposits
The maximum thickness of coarse-grained deposits found on the closest bank to the
thalweg, corresponding to the location of meander bends
Channels have been classified into three types based on their geomorphology and
internal seismic architectures

25. 29 January 2016
Tromsø, Norway
Master thesis in
GEO-3900
UIT
The Arctic University of Norway,
FACULTY OF SCIENCE AND TECHNOLOGY
Department of Geology
Thank you for your attention