The Research Centre for Arctic Petroleum Exploration is happy to present you the program for the ARCEx Annual Conference on Sommarøy, Tromsø, on 22-24 October, 2019. Please note that the program may be updated.

The ARCEx conference will be an event over three days, where researchers, industry partners and authorities are gathered for knowledge-sharing and updates on the latest research results. We are planning three keynote talks, about 20 presentations, poster presentations by the ARCEx fellows, an excursion, and there will be plenty of opportunity for discussions, networking and socializing.

Welcome to Sommarøy, Tromsø, in October!

Time: 22-24 October 2019. Add to your calendar.
Place: Sommarøy Arctic Hotel, Sommarøy, Tromsø.

The Annual Conference 2019 is fully booked. We hope to get more rooms for our participants. If you wish to be on a waiting list, please send an email to ellen.i.hatta@uit.no.

 

Program

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Tuesday 22 Oct 2019

Transportation

10:15 Bus from Naturfagbygget, UiT, Tromsø
10:30 Bus from Prostneset/city centre
10:45 Bus from Tromsø airport Langnes

12:00-12:45 Lunch at Sommarøy Arctic Hotel

12:45 - 14:05 Session 1: Welcome and overview

Welcome address by the ARCEx Director

Alfred Hanssen, UiT The Arctic University of Norway

Tue 12:45 - 12:55

Welcome address by the Research Council of Norway

Siri Friedemann, The Research Council of Norway

Tue 12:55 - 13:05

WP1&2 Geology

Kim Senger, The University Centre in Svalbard, Sten-Andreas Grundvåg, UiT The Arctic University of Norway

Overview and status of ARCEx research work package 1&2 Geology, by work package leaders Kim Senger and Sten-Andreas Grundvåg.

Tue 13:05 - 13:25

WP3 Environmental Risk Management

JoLynn Carroll, Akvaplan-niva & UiT

Overview and status of ARCEx research work package 3 Environmental risk management, by work package leader JoLynn Carroll.

Tue 13:25 - 13:45

WP4 Technology for eco-safe exploration

Tor Arne Johansen, University of Bergen

Overview and status of ARCEx research work package 4 Technology for eco-safe exploration, by work package leader Tor Arne Johansen.

Tue 13:45 - 14:05

14:05-14:30 Break

14:30 - 15:55 Session 2

Keynote #1: “Updated plate reconstructions for the Arctic; from Amerasia to the Eurekan.”

Grace Shephard, Centre for Earth Evolution and Dynamics (CEED), University of Oslo

Abstract:

The incorporation
of digital, self-consistent and temporally continuous Arctic plate
reconstructions is an outstanding challenge in global plate reconstructions,
even for recent times. The temporally punctuating and somewhat spatially
overprinting episodes of rifting, seafloor spreading, subduction, exhumation,
major magmatic events and orogenic building render a complicated kinematic
history. However, multiple recent mapping efforts – including those onshore,
offshore, directly sampled, and remotely acquired - offer a new opportunity to
refine the reconstructions.  This talk will present recent work undertaken
with a large number of international collaborators and cover the most recent
200 Ma history of the circum-Arctic domain. The presentation will showcase both
the traditional rigid plate and more recent deforming plate capabilities of the
GPlates
software, and serves an update since Shephard et al. (2013; Earth Science
Reviews). The talk will focus on the implementation new constraints for the
extent of “true” oceanic crust within the Canada Basin, displacements of the
Chukchi Plateau, sub-parallel lineaments within the Amerasia Basin, a partly
continental Alpha-Mendeleev Ridge, dynamics of the High Arctic Large Igneous
Province, opening of the Makarov and Podvodnikov basins, subduction of the
South Anuyi Ocean, and kinematics associated with the Eurekan
deformation.  Ultimately, this updated reconstruction will deliver a new
generation of paleogeographic maps and a discussion about processes such as
rifting and breakup dynamics, the role of along/within-margin heterogeneity
structure, and the effect of time-dependent rifting rates.

Author:

Grace Shephard, Centre for Earth Evolution and Dynamics (CEED), University of Oslo.

Tue 14:30 - 15:15

“Fault-controlled diagenesis and fluid circulation along a major syn-rift border fault system – the Dombjerg Fault and the Wollaston Forland Basin, NE Greenland.”

Eric Salomon, University of Bergen

Abstract:

During rift climax in marine rift basins, syn-rift border fault systems commonly displace hanging wall deep-water clastics against crystalline basement rocks. Such basement-juxtaposed successions represent challenging reservoir targets in hydrocarbon exploration, and it is therefore of great importance to understand the evolution of fluid flow properties as well as any fault-controlled diagenesis affecting the fault itself and/or adjacent basinal clastics.

Due to limited onshore exposure of such fault zones, studies on their evolution are rare and their impact on fluid circulation and in-fault, near-fault, and hanging wall sediment diagenesis is poorly understood. To tackle this circumstance, we investigate a well-exposed example, namely the Dombjerg Fault in the Wollaston Forland Basin, NE Greenland. Being part of the NE Greenland rift system, this fault displaces Upper Jurassic and Lower Cretaceous syn-rift deep-water clastics against Caledonian metamorphic basement.

Previously, we identified that in addition to a significant ~1 km-wide damage zone, a ~700 m-wide envelope of increased calcite cementation of the sediments developed around the Dombjerg fault core, termed chemical alteration zone. Now, based on U/Pb calcite dating, we are able to show that cementation and formation of this zone started during the rift climax in the Berrisian / Valanginian. Using clumped isotope analysis, we determined a cement formation temperature ~45-65˚C. Temperatures likely do not relate to the normal geothermal gradient, but to elevated fluid temperatures of upward directed circulation along the fault.

Vein formation within the chemical alteration zone clusters between ~125-100 Ma in the post-rift stage, indicating that fracturing in the hanging wall is not directly related to the main phase of activity of the adjacent Dombjerg Fault. Vein formation temperatures range between ~40-90˚C, signifying a shallow buriel depth of the hanging wall deposits.

Further, similar minor element concentrations of veins and adjacent cements argue for diffusional mass transfer, which in turn infers a subdued fluid circulation and low permeability of the fracture network. Hence, our results imply that the chemical alteration zone formed an impermeable barrier quickly after sediment deposition and maintained this state even after fracture formation.

Author:

Eric Salomon, University of Bergen
Atle Rotevatn,
Thomas Berg Kristensen,
Sten-Andreas Grundvåg,
Gijs Allard Henstra,
Anna Nele Meckler,
Axel Gerdes,
Richard Albert Roper

Tue 15:15 - 15:35

“Geological controls on widespread gas leakage at the seafloor in the northern Barents Sea.”

Rune Mattingsdal, Norwegian Petroleum Directorate

Abstract:

During the last couple of
years several research cruises have been carried out in the eastern parts of
the northern Barents Sea. During these cruises one of the recurring research topics
has been mapping of gas flares in the water column. This is done by interpreting
the water column data acquired by the same multibeam echosounder as used for
mapping the bathymetry. During four different cruises, all carried out by the
Centre for Arctic Gas hydrate, Environment and climate (CAGE) at the University
of Tromsø, there has now been mapped many hundreds of gas flares at the
seafloor in this area. The cruises have particularly focused on the southern
parts of Storbanken (just north of the Olga basin) and on the Kong Karls Land
platform. One of the cruises also used a ROV to take in-situ samples of the gas
bubbles leaking out at the seafloor.

As participants on these CAGE
cruises the Norwegian Petroleum Directorate (NPD) has used our knowledge of the
subsurface to relate the gas leakage at the seafloor to geological features and
structures observed on seismic data. The results so far show a very strong correlation
between the gas flares and the subsurface geology. Due to severe erosion in the
area sedimentary rocks of Mesozoic age, both Cretaceous, Jurassic and Triassic
of age, subcrop at the seafloor. Combined with the fact that the whole area has
a very thin, if none, cover of Quaternary sediments, which could prohibit the
gas from leaking directly vertically from the geological layers into the water
column, the direct linkage of the seafloor leakage to the subsurface geology is
very robust.

The gas leakage seems to
primarily be related to three main geological factors: 1) faults going all the
way from the reservoir rocks to the seafloor, 2) where reservoir and cap rocks
sub-crop at the seafloor, 3) the crest of large geological structures where
erosion is into the Triassic.

Author:

Rune Mattingsdal, Norwegian Petroleum Directorate, Harstad

Tue 15:35 - 15:55

15:55-16:20 Break

16:20 - 17:20 Session 3

“An empirical approach to estimating hydrocarbon column heights for improved pre-drill volume prediction in hydrocarbon exploration.”

Isabel Edmundson, University of Bergen

Abstract:

Pre-drill volume estimation in exploration involves a number of input parameters that each carry a degree of uncertainty. The largest contributor to this uncertainty is almost always the hydrocarbon column height, which in turn is controlled by both charge and seal behaviour. However, it is this parameter that exploration and production companies often find the hardest to predict, partly due to the lack of sufficient empirical data from existing fields and discoveries. This study introduces a new empirical dataset from the Norwegian Continental Shelf, which aims to improve confidence in hydrocarbon column height prediction. The column height, trap height and overburden thickness have been measured for over 240 discoveries across the Norwegian Continental Shelf. Using this dataset, the trap-fill ratio for each discovery is calculated to assess what proportion of each structure is filled by hydrocarbons. The data from the 242 measured discoveries have been aggregated into a probability tree to calculate the likelihood of a discovery containing different ranges of trap fill, depending on its burial depth and trap height. Results show that for a discovery with a given trap height, the probability of recording 100% fill increases when the overburden thickness increases. Equally, when the trap height increases for a given overburden thickness, the probability of discovery 100% trap fill decreases. These findings, amongst others strongly indicate the need to integrate a structure’s dimensions when assessing seal capacity, and suitable ranges of hydrocarbon column heights to use when estimating pre-drill volumes. It is not suggested that this numerical approach replaces detailed geological evaluation of the prospect and trap specific geology. The strength lies in integrating the probability- and geological-based approaches together to reduce uncertainty surrounding both risking of the seal capacity and volumetric calculations. Although the dataset comes from the Norwegian Continental Shelf, the lessons learnt are applicable to hydrocarbon exploration in basins worldwide.

Authors:

Isabel Edmundson, University of Bergen
Roy Davies, Wintershall Dea
Lars Frette, Capricorn Energy
Sean Mackie, Wintershall Dea
Emilie Kavli, IFP School
Atle Rotevatn, University of Bergen
Graham Yielding, Badley Geoscience
Alex Dunbar, Wintershall Dea

Tue 16:20 - 16:40

“Wisting Geophysical Toolbox.”

Lars Martin Moskvil, OMV (Norge)

Abstract:

Wisting is a shallow oil discovery in the Norwegian Barents Sea approximately 300km north of Hammerfest. The most prominent reservoir is the Upper Triassic to Middle Jurassic Realgrunnen Subgroup (Stø-,Nordmela- and Fruholmen Formation), with the Fuglen Formation provides the cap rock. The top reservoir is situated at a depth of 650m tvdss, only 250 below the mudline. To date, OMV have drilled six exploration and appraisal wells, including one horizontal appraisal well.

The Wisting discovery contains a unique geophysical laboratory with a wide range of data; such as 3D seismic data, extensive 2D site survey data, an extensive well log suite and 3D CSEM data. To be able to further mature the Wisting discovery towards field development, improved ability to perform detailed reservoir characterization and a better understanding of the reservoir architecture is considered crucial. To achieve this, OMV acquired a new ultra-high resolution seismic dataset (P-cable) in 2016. The new P-cable dataset is providing a huge uplift in the detailed mapping of the geometry in the Realgrunnen Subgroup and the fault definition for the Wisting field. The interpretation of the P-Cable data has reduced the uncertainties for both reservoir volume estimation and geological and flow simulation models to enable improved drainage strategy for development concepts and reduction the uncertainty of well placements.

As part of the latest well operation (7324/8-3) in 2017, a field test of microseismic monitoring was performed. Ocean Bottom Cables (OBC) placed on the seafloor were monitoring the entire well operation. This field test provided Wisting with important information for further maturing the optimal monitoring solutions for the field development.

A key contributor to developing Wisting in a robust way is to integrate all the data (well data, seismic data, CSEM data, and geological understanding) and work closely as multi-disciplinary team where we use the data in the most efficient manner.

Authors:

Lars Martin Moskvil, OMV (Norge)
Jan Freddy Strømmen, OMV (Norge)
John Reidar Granli, OMV (Norge)
Kjetil Krathus-Larsen, OMV (Norge)

Tue 16:40 - 17:00

“Seal characterization in the uplifted basins on the Barents Shelf, from the Hoop area to the Haapet Dome.”

Renate S. Paulsen, UiT The Arctic University of Norway

Abstract:

Top seal integrity on the uplifted Barents Shelf has for a long time been considered as a major risk factor for the companies exploring for oil and gas on the highly uplifted Barents Shelf. Cenozoic uplift of the Barents Shelf and its previous deep burial generally complicates evaluation of the petroleum system elements due to the late effects of the uplift. During burial the composition and behaviour of the sediments will change as a response to varying to pressure and temperature, i.e. diagenesis. The amount of uplift and removal of overburden may also control whether the caprock will keep its seal integrity over the geological time scale, with the additional fluid-related effects including gas expansion and fluid-re-migration.

The Middle to Upper Jurassic Fuglen and Hekkingen formations are shale-dominated units, which represent shelf deposits that accumulated during maximum transgression. The dominance of mudstones and shales make them ideal as potential regional sealing units, as was proven in a number of discoveries and fields.

Top seal characterization is particularly important for understanding and predicting caprock behaviour in uplifted basins, and various methods can be utilized to evaluate the sealing units. The concept of seal capacity and integrity is evaluated based on the mechanical and chemical character of the caprock, including fracture characterization, brittleness/ductile behaviour, permeability and the capillary entry pressure inter alia.

In this study, we evaluate data from 15 wells from the Hoop area towards the Haapet Dome. Many of these wells primarily targeted the Realgrunnen Subgroup, which to date is the most prolific reservoir unit in the Barents Sea. Due to severe uplift of the northern part of the exploration area, these reservoir units are capped by an extremely thin overburden, including the Fuglen and Hekkingen formations. The main objective of this study is to investigate the effect of burial and uplift on the Fuglen and Hekkingen intervals by using estimated burial curves and conceptual models for the burial and uplift history. The transition from ductile to brittle deformation is crucial for seal capacity and integrity, and can vary on local scale, and it is therefore important to understand where and why these transitions occur.

The structural framework has been established through seismic interpretation and modelling, and will facilitate in tying the wells to the regional stratigraphy. Furthermore, the rocks chemical and mechanical behaviour, which are calculated from the available wire-line logs, is governed by the elastic modulus. How the rock respond to stress and whether it maintains fractures are determined by the Poisson’s ratio and the Young’s modulus, which are strongly affected by burial and uplift. The expectation is therefore to observe a change in ductile-brittle behaviour by comparing the modulus to the bulk density of the investigated intervals.

Understanding the lateral distribution and seal integrity through seal characterization can be important for lowering the exploration risk on the uplifted Barents Shelf, and accordingly be beneficial for the overall understanding of the regional geology in the area.

Authors:

Renate S. Paulsen, UiT The Arctic University of Norway
Sten-Andreas Grundvåg, UiT The Arctic University of Norway
Kim Senger, The University Centre in Svalbard
Eirik Stueland, OMV (Norge)

Tue 17:00 - 17:20

17:20-19:00 Break

19:00 Posters and tapas

Poster titles

“Vertical flux in the Arctic – (how) can high latitude observations contribute to our understanding of the POC attenuation?”
Ingrid Wiedmann (UiT), María Villa Alfageme, Elena Ceballos Romero, Feliciano de Soto, Morten H. Iversen, Angelika Renner

“The deformational evolution in a hanging wall damage zone of a syn-rift border fault system – the Dombjerg Fault, NE Greenland.”
Eric Salomon (University of Bergen)

“A review of Cenozoic uplift and erosion in the Norwegian Barents Sea.”
Amando Lasabuda (UiT), Jan Sverre Laberg (UiT), Jan Inge Faleide (UiO), Stig-Morten Knutsen (NPD), Tom Arne Rydningen (UiT), Alfred Hanssen (UiT)

“WNW-ESE-striking Timanian faults in Svalbard.”
Jean-Baptiste P. Koehl (UiT/UiO)

“Short-term exposure to chemically dispersed oil is more harmful to Northern shrimp larvae than mechanically dispersed oil.”
Frederike Keitel-Gröner (NORCE), Maj Arnberg (Akvaplan-niva), Renée K. Bechmann (NORCE), Emily Lyng (NORCE), and Thierry Baussant (NORCE)

“Lower Cretaceous source rocks in the SW Barents Sea.”
Andreas H. Hagset (UiT), Sten-Andreas Grundvåg (UiT), Balazs Badics (Wintershall Dea), Atle Rotevatn (UiB), Roy Davis (Wintershall Dea)

“Organic facies influence on bitumen-derived thermal maturity parameters in Lower–Upper Triassic shales, Edgeøya, Eastern Svalbard.”
Fredrik Wesenlund (UiT), Victoria S. Engelschiøn (UiO), Sofie Bernhardsen (NTNU), Sten-Andreas Grundvåg (UiT), Olaf Thiessen (Equinor ASA), Jon Halvard Pedersen (Lundin Norway AS), Jon Erik Skeie (Aker BP ASA)

“Seismic surface wave investigations of frozen ground in Adventdalen, Svalbard.”
Rowan Romeyn (UiT), Helene Meling Stemland (UiB), Alfred Hanssen (UiT), Tor Arne Johansen (UiB), Bent Ole Ruud (UiB)

"North Atlantic-Arctic tectonics related to the wider Barents Sea paleogeography and basin evolution."
Mohamed Mansour Abdelmalak (UiO)

"Naturally Occurring Underpressure – A Global Perspective."
Thomas Birchall (UNIS), Kim Senger (UNIS), Richard Swarbrick (Swarbrick GeoPressure Consultancy Ltd)

"Cenozoic sedimentary environments on the Vesterålen continental margin."
Stine Bjordal Olsen (UiT), Tom Arne Rydningen (UiT), Jan Sverre Laberg (UiT), Jim Myrvang (Aker BP ASA), Amando Lasabuda (UiT)

"Polar cod early life stages under a warming scenario exhibit extreme sensitivity to low levels of crude oil."
Morgan Lizabeth Bender (UiT), Julia Giebichenstein (UiT), Ragnar Teisrud (UiT), Jennifer Laurent (UiT), Marianne Frantzen (Akvaplan-niva), James Meador (Ecotoxicology and Environmental Fish Health Program, Northwest Fisheries Science Center, NOAA Fisheries), Lisbeth Sørensen (SINTEF Ocean), Bjørn Henrik Hansen (SINTEF Ocean), Helena C Reinardy (Scottish Association for Marine Science and UNIS), Benjamin Laurel (Fisheries Behavioral Ecology Program, Alaska Fisheries Science Center, National Marine Fisheries Service, NOAA), Jasmine M Nahrgang (UiT)

"Anatomy of the evaporite accumulation and salt wall evolution in Tiddlybanken Basin, southeastern Norwegian Barents Sea."
Muhammad Hassaan (UiO), Jan Inge Faleide (UiO/UIT), Roy Helge Gabrielsen (UiO), Filippos Tsikalas (Vår Energi /UiO)

"Seismic imaging of low-displacement carbonate hosted faults with insights from seismic modelling."
Vilde Dimmen (UiB), Atle Rotevatn (UiB), Isabelle Lecomte (UiB)

“Different aspects of detection of karstified reservoirs - case examples from gravimetry ​and seismic interpretation.”
Terje Solbakk (NTNU), Philip Ringrose (NTNU), Christine Fichler (NTNU), Tore Svånå

"Stress and deformation analysis in the Barents Sea in relation to Paleogene transpression along the Greenland-Eurasia plate boundary."
Sébastien Gac (UiO), Alexander Minakov (UiO), Grace E. Shephard (UiO), Jan Inge Faleide (UiO & UiT) Sverre Planke (UiO & VBPR)

"East-west trends in palaeoenvironment and oxygenation in the Middle Triassic Botneheia Fm., Svalbard."
Victoria Sjøholt Engelschiøn (UiO), Øyvind Hammer (UiO), Jørn Hurum (UiO), Fredrik Wesenlund (UiT), Sofie Bernhardsen (NTNU), Atle Mørk (NTNU)

"Seismic signatures of warming permafrost."
Helene Meling Stemland (UiB), Tor Arne Johansen (UiB), Bent Ole Ruud (UiB)

"The role of faults in hydrocarbon leakage: insights from two cases studies in the Barents Sea."
Isabel Edmundson (UiB), Atle Rotevatn (UiB), Roy Davies (Wintershall Dea), Graham Yielding (Badley Geoscience), Kjetil Broberg (Wintershall Dea)

“From sound source to perception: seismic surveys and cetacean hearing.”
Hannah Kriesell and Martin Landrø (NTNU)

"Diffraction separation by diffraction stacking."
Vemund Stenbekk Thorkildsen (UiO)

"Seal Integrity in the Uplifted Basins in the greater Hoop Area on the Northern Barents Shelf."
Renate Strugstad Paulsen (UiT), Sten-Andreas Grundvåg (UiT), Kim Senger (UNIS), Eirik Stueland (OMV (Norge) AS), Lars Martin Moskvil (OMV (Norge) AS)

"Geochemical signal of Triassic successions at the Svalis Dome, SW Barents Sea – illustrating the potential of the XRF Core Scanner."
Sigrun Maret Kvendbø Hegstad (UiT), Juha Ahokas (Aker BP), Matthias Forwick (UiT), Sten-Andreas Grundvåg (UiT)

Tue 19:00 - 20:30

20:30-23:00 Seaside bathhouse and outdoor jacuzzi

Wednesday 23 Oct 2019

09:00 - 10:25 Session 4

Keynote #2: "The Nansen Legacy"

Marit Reigstad, UiT The Arctic University of Norway

Wed 09:00 - 09:45

“Who feeds the benthos in the Arctic Ocean Basin?”

Ingrid Wiedmann, UiT The Arctic University of Norway

Abstract:

The remarkable observations of a rich benthic community in hot spot areas within the central Arctic basin contradict the current paradigms of low Arctic annual primary production, vertical carbon export and carbon input to the sea floor. In the present work, we synthesize published and so far unpublished data to set up a carbon budget for the central Arctic Ocean. At first sight, this budget identifies a major mismatch between primary production, the carbon needs of zooplankton and the measured vertical export flux of carbon on the one hand, and the carbon demand of the benthos on the other hand. We point out potential reasons for the observed mismatch such as challenges in the estimation of primary production under sea ice and a potential underestimation of vertical carbon flux by sediment traps. In addition, we estimate the advected carbon contributed by sub-Arctic zooplankton for the benthos when dying in high Arctic conditions. In conclusion, this work emphasizes the need of a better understanding of the carbon budget in the Arctic. The locally thriving Arctic benthic ecosystems suggest a substantial carbon flux to the seafloor which is currently not explained by our export flux.

Authors:

Ingrid Wiedmann, UiT The Arctic University of Norway
Bodil Bluhm, UiT The Arctic University of Norway
Eva-Maria Nöthig, Alfred Wegener Institute
Elizaveta Ershova, UiT The Arctic University of Norway
Ksenia Kosobokova, Shirshov Institute of Oceanology, Russian Academy of Sciences
Rolf Gradinger, UiT The Arctic University of Norway

Wed 09:45 - 10:05

“Decadal patterns of benthic fauna on the northern Svalbard shelf: Indicators of community structure in an era of climate change.”

Michael Carroll, Akvaplan-niva

Abstract:

Seabed (benthic) communities can be biologically rich and diverse, are food for pelagic species, including those of commercial interest, and perform diverse ecosystem services. Because characteristics of benthic communities vary in relatively predictable ways in response to different environmental influences, examining changes in benthic community characteristics through time provides information on natural baseline variations and anthropogenic stressors. It is this conceptual basis that largely forms the biological framework of the Norwegian offshore monitoring program for O&G installations.
Substantial climatic changes are taking place in the Arctic, not the least of which are rapidly warming air masses, changes in ocean heat content, ocean circulation patterns and distributions of water masses, attenuation of sea ice, and changes in the location, magnitude, and types of photosynthetic production occurring in the surface water. All these factors have implications for Arctic marine food webs. A key question is whether we can equivocally detect the result of these changes on key ecosystem components.
In 2018, a cruise organized by ARCEx and the Arctic Marine Geology and Geophysics PhD School at the Institute of Geosciences, UiT-The Arctic University of Norway investigated remote areas at the shelf, slope and deep Arctic Ocean basin on the northern and eastern margin of Svalbard and the Kvitøya trough. The complex basin bathymetric and hydrographic features and sea ice characteristics in this area provide an ideal natural laboratory to examine changes in the structure of natural biological communities and on ecosystem functioning. Fortunately, benthic communities and seabed processes were thoroughly studied in this area in 2003-2005 through two expansive Norwegian Research Council Projects. This provided an unique opportunity to examine how the benthic communities have changed over a 15 year window of time by comparing data sets from these earlier investigations with the newly collected ARCEx data set.
During the 2018 cruise on the RV Helmer Hanssen, ArcEx benthic specialists were able to resample 8 stations in the region using the same personnel, equipment, and sampling and laboratory analytical methodology that was used during the 2003-2005 expeditions. Several patterns emerged from the 2018 datasets when compared to the earlier 2003-2005 data. The organic content of the sediment was lower, while overall faunal abundance was higher than earlier. Changes in faunal biomass varied somewhat with station. These results suggest that there has been a shift in community structure from larger to smaller organisms, with different phyletic groups dominating the community. This would be consistent with a shift in food availability and quality that favors smaller, opportunistic organisms at the expense of larger, specialist species.
This new understanding of the baseline variation is important for the petroleum industry to obtain an accurate picture of the seafloor environment for the planning and execution of operations in the Barents Sea.

Author:

Michael Carroll, Akvaplan-niva

Wed 10:05 - 10:25

10:25-10:50 Break with group photo

10:50 - 11:50 Session 5

“Effects of a complex petroleum mixture to Barents Sea key fishes – recent results on species sensitivity and a novel hypothesis that may lead to a paradigm shift.”

Jasmine Nahrgang, UiT The Arctic University of Norway

Abstract:

Climate change and the northward shift of the marginal
ice zone may portend a significant expansion of the industrial activities in
the coming years. Although technological advances and regulations may help
lower the potential impacts of accidental oil spills, their environmental and
societal consequences can be tremendous and long-lasting. A large range of
studies document the high toxicity of crude oil to fishes, and in particular
for early life stages (ELS). In the past years, we have conducted a series of
experiments to elucidate the developmental effects of crude oil to early
life stages of the Barents Sea capelin (Malotus villosus) and polar
cod (Boreogadus saida). This series of experiments provided a very
contrasting image of the sensitivities of these two key species with
distinctive life history traits. Furthermore, we discuss the current
understanding regarding the causative agents to fish ELS adverse effects based
on the past 20 years of research on crude oil toxicity. We conclude that
the available data does not support the current understanding of polycyclic
aromatic hydrocarbons being the primary causative agents for the observed
toxicity and suggest an alternate hypothesis.

Author:

Jasmine Nahrgang, UiT The Arctic University of Norway
Marianne Frantzen, Akvaplan-niva
Morgan L. Bender, UiT The Arctic University of Norway
Ireen Vieweg, UiT The Arctic University of Norway
James P. Meador, Ecotoxicology and Environmental Fish Health Program, Northwest Fisheries Science Center, NOAA Fisheries

Wed 10:50 - 11:10

“Is exposure to chemically-dispersed oil more harmful to early stages of the Northern shrimp Pandalus borealis than mechanically-dispersed oil?”

Frederike Keitel-Gröner, NORCE

Abstract:

The overall objective of this research is to support decision-making and select the best response options, such as use of chemical dispersants, following an oil spill to minimize the net environmental impacts to key planktonic species in northern ecosystems.

Here, Pandalus borealis (Northern shrimp) larval stages were exposed to environmentally realistic concentrations of chemically dispersed oil (CDO, dispersant application), mechanically dispersed oil (MDO, natural dispersion) and dispersant only (internal control). Control conditions (seawater only) served as reference. Two experiments were conducted. In the first experiment, shrimp larvae were exposed for 24h to three concentrations of MDO and CDO (Slickgone NS), achieved by diluting the high concentration (H, MDO <6mg/L and CDO <20 mg/L) 1:10 (Medium concentrations) and 1:100 (Low concentration), followed by a short recovery period (max. 9 days). With CDO, lower survival and feeding rates as well as slower larval development were observed compared to MDO during exposure and until the end of the recovery period. In the second experiment, shrimp larvae were exposed (H only) to durations as short as 6h and 1h, and recovery in clean seawater was followed for 30 days. While feeding was reduced directly after exposure, survival, growth and development were impaired significantly during recovery. The results show that exposure times as short as 1h have negligible effects on the larval fitness, while after 6h exposure all endpoints were affected with more severe and lasting impacts after exposure to CDO. Overall, the conclusion from these experiments is that early life stages of shrimp are more sensitive to CDO than to MDO under the tested conditions, but more research is needed to understand the long-lasting consequences for shrimp populations. These results are considered relevant for the Net Environmental Benefit Analysis (NEBA) to trade off the negative aspects on larval effects in the water column against the positive ones for other important long-lived wildlife of northern ecosystems such as seabird populations.

Authors:

Frederike Keitel-Gröner*1, Maj Arnberg2, Renée K. Bechmann1, Emily Lyng1, Stig Westerlund1 and Thierry Baussant1
1 NORCE Norwegian Research Centre, Mekjarvik 12, 4072 Randaberg, Norway
2 Akvaplan-niva, Havnegata 9, 7010 Trondheim, Norway

*E-mail (corresponding author): frke@norceresearch.no

Wed 11:10 - 11:30

“Anoxia and mass death – a high-resolution biofacies study of the Ladinian (Middle Triassic) Blanknuten Mb., Botneheia Fm. on Edgeøya”

Victoria Sjøholt Engelschiøn, Natural History Museum, University of Oslo

Abstract:

The Middle Triassic organic-rich, black shales of the Botneheia Fm. is divided into the lower Muen and upper Blanknuten mbs. The formation was deposited in a second-order transgressive-regressive regime, where the characteristic cliff-forming, phosphorous shales of the Blanknuten Mb. formed during high-stand sometime in the Ladinian. Fossils, especially bivalves, are found in rock-forming quantities in the middle of the member. Numerous ichthyosaur specimens and bivalve beds have been described by previous workers as the result of mass-mortality events. The Middle Triassic had high biological productivity in the upper water column along with occasional algal blooms. The combination is thought to have reduced oxygenation levels at depth, causing anoxia combined with sulphurous bottom-waters (a “euxinic pillow”). However, among the fossiliferous beds are also layers of Thalassinoides sp. burrows, an ichnotaxon usually associated with oxygenated environments. If  previous interpretations of mass-death caused by anoxia are correct, the bioturbated layers are episodes of oxygenated bottom-waters. This study investigates possible scenarios for such oxygenation events, and whether the bivalve beds represent true mass-mortality events. A high-resolution log is presented, using well-exposed bedding surfaces on the Muen plateau mountain (western Edgeøya) to discuss the correlation between taphonomy (preservation of fossils), bioturbation and depositional environment.

Authors:

Victoria Sjøholt Engelschiøn, Natural History Museum, University of Oslo
Sofie Bernhardsen, Norwegian University of Science and Technology
Fredrik Wesenlund, UiT The Arctic University of Norway
Øyvind Hammer, Natural History Museum, University of Oslo
Jørn Hurum, Natural History Museum, University of Oslo
Atle Mørk, Norwegian University of Science and Technology

Wed 11:30 - 11:50

11:50-12:40 Lunch

12:40 - 15:40 Excursion: “Precambrian geology and Mesozoic rift-tectonic landscapes of western Troms, Barents Sea margin”

Excursion plan

Steffen Bergh, Jean-Baptiste Koehl, Harald Hansen, UiT

The field excursion this year takes the conference participants to the Hillesøya–Sommarøya area on Kvaløya, Troms, both on foot and on boat.

Bring walking shoes, weatherproof clothes, gloves and wooly hat.

Excursion leaders:

Steffen Bergh, Jean Baptiste Koehl, and Harald Hansen, UiT The Arctic University of Norway

Description of the Hillesøya-Sommarøya area on Kvaløya, Troms:

Kvaløya, including Sommarøya and Hillesøya, are located within a major Paleozoic–Mesozoic horst composed of Neoarchaean and Palaeoproterozoic basement rocks, the West Troms Basement Complex. This basement unit is thought to be continuous with the Fennoscandian Shield of Russia (Kola), northern Finland and Sweden, linked below the Scandinavian Caledonides. Within this horst, 2.89–2.70 Ga tonalities, trondhjemites, granitoids, and diorites were deformed, metamorphosed and turned into TTGD-gneisses ca. 2.69–2.55 Ga. These gneisses are well exposed in outermost Kvaløya. During a major rifting event in the Fennoscandian Shield at c. 2.4-2.2 Ga produced mafic dyke swarms that crosscut TTGD gneisses in Ringvassøya, Kvaløya, and Senja. During this rifting event numerous volcano-sedimentary basins (greenstone belts) were deposited on top of the Neoarchaean basement rocks, e.g., Astridal, Torsnes, Mjelde-Skorelvvatn, Vanna supracrustal belts. These belts and the surrounding TTGD gneisses were deformed and metamorphosed during the Late-Svecofennian (1.8-1.7 Ga) accretionary orogeny into lens-shaped, NW–SE-trending shear belts, which now separate the TTGD gneisses (Bergh et al. 2010, 2012, 2015). The deformation was characterized by NE–SW crustal shortening/accretion with NE-directed thrusting and tight folding (D1), subsequent major upright folding (D2), and a late-stage partitioned transpression event leading to the formation of major subvertical folds and lateral strike-slip shear zones (D3). Prior to, and during the main accretionary event (1.8–1.77 Ga), large portions of the TTGD gneisses were partly melted and injected as large-scale granitic sheets (Ersfjord Granite) into the remaining portions of the TTGD gneisses in Kvaløya, which was followed by the intrusion of late/post-orogenic granite pegmatite dykes. The field excursion on Hillesøya and Sommarøya will explore some of these basement features that may have controlled later, Caledonian contraction and post-Caledonian rift-tectonic events along the southwestern Barents Sea margin.
Rocks of the West Troms Basement Complex were only mildly deformed during the Caledonian Orogeny, and started to exhume during late/post-orogenic collapse of the Caledonides along bowed extensional shear zones and/or along normal brittle faults, e.g., Hillesøya, Tussøya, Rekvika faults on Kvaløya, and Sørøya–Ingøya shear zone offshore. Major post-Caledonian (Paleozoic–Mesozoic) faults strike on average NE–SW and dip to the northwest producing offshore basins bounded by rotated fault blocks, and palaeosurfaces dipping gently toward the continent. These Paleozoic–Mesozoic structures are in part responsible for a peculiar asymmetric, wedge-shaped landscape and topography that characterize many coastal islands from Lofoten to Vanna, with steeply NW-dipping scarps and gently SE-dipping palaeosurfaces. These landscape features can be seen in Håja, Hillesøya and Tussøya (Indrevær & Bergh 2014). Comparison of the onshore asymmetric landscapes and offshore tectonic architecture supports the idea that disrupted low-relief surfaces bounding steep scarps, ridges and depressions onshore in Kvaløya, as well as in Lofoten, represent tectonic inheritance of a tilted basement–cover surface, rotated fault blocks and half-graben basins from Paleozoic–Mesozoic rifting of the margin.
The post-Caledonian normal faults also provided preferential pathways for fluid circulation during or shortly after tectonic movement, e.g., in Tussøya, where such fluid circulation resulted into a red-stained color of FeHO in granitic rocks of the West Troms Basement Complex. In addition, the Tussøya Fault Zone contain Cu-mineralization along the main fault surface. Analogous normal faults bounding large hydrocarbon-rich sedimentary basin also exist off the coasts of northern Norway.

Wed 12:40 - 15:40

15:40 - 17:00 Session 6

“From Transpression to transtention along the W Svalbard margin: tectonics and sedimentation in the Forlandssundet Basin.”

Per Terje Osmundsen, Norwegian University of Science and Technology

Abstract:

The Forlandsundet Basin in western Svalbard records the change from transpressional to transtensional tectonics along the northernmost parts of the Northeast Atlantic margin. The basin thus marks the change from the processes that created the west Spitsbergen Orogen to those responsible for the creation of the spreading ridges in the northernmost Atlantic Ocean. Formation of the Forlandsundet basin furthermore heralded km-scale uplift of the Central Tertiary basin and formation of the Arctic landscapes presently exposed in Svalbard. We present new structural, sedimentological and geochronological data from the Forlandsundet basin and discuss their implications with respect to the post-Eocene tectonic evolution of the Svalbard archipelago.

Authors:

Per Terje Osmundsen, Norwegian University of Science and Technology
Niklas Schaaf, The University Centre in Svalbard
Thomas F. Redfield, Geological Survey of Norway
Roeland van der Lelij, Geological Survey of Norway
Morgan Ganerød, Geological Survey of Norway
Jasmin Schoenenberger, Geological Survey of Norway
Kim Senger, The University Centre in Svalbard

Wed 15:40 - 16:00

"Perspectives from recent exploration activities in the Northwestern Barents Sea after 7321/4-1 Gråspett well."

Arnaud Santoire, Wintershall Dea

Author: Arnaud Santoire, Wintershall Dea.

Wed 16:00 - 16:20

“Carboniferous graben structures, evaporite accumulations and tectonic inversion in southeastern Norwegian Barents Sea.”

Muhammad Hassaan, University of Oslo

Abstract:

Improved
resolution reprocessed 2D multi-channel seismic reflection profiles, combined
with exploration wells and stratigraphic boreholes penetrating upper Paleozoic
sequences on the eastern Finnmark Platform were utilized particularly to analyse
the Carboniferous graben system, evaporite bodies distribution, domes and salt
wall in the southeastern Norwegian Barents Sea and east Finnmark Platform.
Seven deep-seated Carboniferous grabens, not previously described and named,
were defined and informally named as grabens G1-G7. Five evaporite bodies,
named EB1-EB5, have been mapped in detail. During late Devonian, the study area
was dominated by a central structural high region (Fedynsky High) rimmed by sag
basins to the north and south it. We suggest that late Devonian-early
Carboniferous (Mississippian) NE-SW oriented stress regime as suggested for the evolution of the Pechora
Basin, eastern Barents Sea, and Olga-Sørkapp region also created the NW-SE
striking graben structures (G1-G5) in the southeastern Norwegian Barents Sea, mainly
exploiting the Timanian Orogen structural grain. In the early Pennsylvanian, the NE-SW trending Nordkapp Basin
dissected the already existing G6 and G7 grabens. Pennsylvanian to early
Permian evaporite units were deposited. The temporal relationship suggests that
the evaporites were deposited as post-rift sequences within the Carboniferous
grabens of the southeastern Norwegian Barents Sea and as syn-rift or early post-rift sequences within the Nordkapp Basin. The
discrepancy in syn-rift to post-rift basin conditions affected the distribution
and thickness of the accumulated evaporites, partly or fully occupying the
available accommodation space.

Evaporite
bodies EB1, EB3, and EB5 are correlated
to the Gipsdalen Group halite and non-halite lithologies (i.e. anhydrite-related compositions) with less thickness,
while evaporite body EB4 contained mobile halite lithology and EB2 comprised
of transitional lithology from graben margin (non-mobile) to the center
(mobile). The deep-seated structures constrained the accumulation and facies
variations of the evaporites and strongly
controlled the distribution and partially the evolution of the
stratigraphically shallower domes. The effect of salt mobilization on the dome
evolution depended on the relative amount of lithologies with mobile to
immobile properties, and the relative stratigraphic thickness of each unit. The
NW-SE trending salt wall evolution is complex, varies along-strike, and has
affected the structural development of the Signalhorn Dome that was instigated
during late Triassic due to the far-field stresses from the evolving Novaya
Zemlya fold-and-thrust belt.

The Haapet, Veslekari, Alpha and Beta domes were
instigated and the salt wall was rejuvenated during late Triassic due to
compressional stresses propagating from the Novaya Zemlya fold-and-thrust belt as
these structures were located in the relative proximity. Several studies on the
Barents Sea-Svalbard region have similarly recorded the results of far-field
compressional stresses attributed to the Novaya Zemlya fold-and-thrust belt. All
of the structural elements were mildly reactivated during upper Jurassic and
earliest Cretaceous. However, the
exact causes of this reactivation are difficult to be deciphered in detail due to lack of dense seismic
reflection coverage and relatively poor seismic resolution in the southeastern
Norwegian Barents Sea. Prograding shelf platform complex sediments during early
Cretaceous buried the domes and the salt wall until reactivation of the
deep-seated Carboniferous grabens led to the reactivation of these structures
and to the erosion of the post-lower Cretaceous strata over their crest.
We infer an early-middle Eocene timing for the main phase of reactivation of
the domes and salt wall, probably in response to regional compressional
stresses related to the transpressional Eurekan/Spitsbergen orogeny.

Authors:

Muhammad Hassaan, University of Oslo
Jan Inge Faleide, University of Oslo
Roy Helge Gabrielsen, University of Oslo
Filippos Tsikalas, Vår Energi & University of Oslo

Wed 16:20 - 16:40

Title tba. Aker BP

Wed 16:40 - 17:00

17:00 - 19:00 Break / individual meetings

17:20 - 18:00 General Assembly

1 representative per consortium member.

19:00 Conference dinner

Thursday 24 Oct 2019

09:00 - 10:25 Session 7

Keynote #3: “Risk based decision support for arctic activities"

Prof. Seth Guikema, Industrial and Operations Engineering, Civil and Environmental Engineering, University of Michigan

Abstract:

To be provided.

Author:

Prof. Seth Guikema, Industrial and Operations Engineering, Civil and Environmental Engineering, University of Michigan

Thu 09:00 - 09:45

“Tacit and explicit assumptions: Conceptual clarification and environmental risk assessment applications.”

Roger Flage, Universitetet i Stavanger

Abstract:

In quantitative risk assessments, several explicit assumptions need to be made, to compute the risk metrics addressed. Such assumptions may, for example, relate to the number of drilled wells, to the reliability of protection systems, or to the response of a system exposed to a hazard. In addition, come potential tacit assumptions, for example, when making a probability judgement about an event to occur. The probability judgement is based on some knowledge – which essentially captures data, information, and justified beliefs – and here tacit assumptions may exist, even if explicit assumptions have not been formulated: for example, a belief about how a system works. The probability and resulting risk metrics are conditional on this knowledge including these assumptions, and the strength of this knowledge and the ‘risk’ related to potential deviations from these assumptions needs attention. This talk addresses the concept of a risk assessment assumption, the main aims being to clarify the issues raised and to provide guidance on how to formulate the background knowledge to distinguish between explicit and non-explicit (tacit) assumptions. The talk thus provides a sharper conceptual basis for addressing such assumptions, and also some recommendations for dealing with these in practice. Examples are highlighted related to environmental risk assessment.

Authors:

Roger Flage, Universitetet i Stavanger
Tore Askeland, Statens Vegvesen / University of Stavanger

Thu 09:45 - 10:05

“Environmentally Friendlier Seismic Acquisitions.”

Peter Hanssen, Equinor

Abstract:

This paper presents an overview of the technologies available and currently under development to perform offshore seismic surveys with less environmental impact. Most, if not all the developments, are driven by the oil & gas companies and the seismic contractors. They include methods to reduce the impact of the active sources or they focus on reducing the acquisition time for a seismic survey. Efficient methods are also important to reduce the costs, but the inclusion of environmentally friendlier technologies safeguards the license to operate when regional restrictions increase.

Existing geophysical methods in combination with new and upcoming technologies not only make it possible to save survey costs and ensure freedom to operate, but they may also record better data. To reduce the time a survey lasts and impact on the environment, e.g. avoid a spawning period, several simultaneous source acquisition methods are available. These reduce the number of saillines necessary and by that reduce the duration and cost of a survey. Other technologies focus on spreading the standard impulsive shots over time to reduce the Sound Pressure Level (SPL) and/or Sound Exposure Level (SEL). Additionally, new sources have been built which can avoid the most harmful frequencies.

The technologies presented are multi-source surveys, Seismic Apparition, eSeismic, eSource, and marine vibrators. New developments related to towed marine vibrators fulfil all three requirements: less environmental impact, increased efficiency, and better data. Reducing SPL and SEL, avoiding unnecessary frequencies, and reducing saillines will be the standard acquisition requirements in the future.

Author:

Peter Hanssen, Equinor

Thu 10:05 - 10:25

10:25-10:50 Break.

10:50 - 11:50 Session 8

“Time-lapse surface seismic: Possible applications and examples from Svalbard.”

Helene Meling Stemland, University of Bergen

Abstract:

Arctic surface temperatures are rapidly increasing, causing thawing of currently frozen ground. Thawing can lead to subsidence because unfrozen ground is more deformable than frozen ground, which can have huge consequences for infrastructure or settlements built on top of permafrost. Areas with saline permafrost are particularly at risk of following geomorphic consequences because saline pore-water gradually changes phase, and therefore even small subzero temperature variations can lead to significant changes in the degree of freezing.

To detect and monitor permafrost degradation, non-intrusive methods are desirable because they can cover large areas with minimal environmental impact. Since the degree of freezing of pore-water affects the effective elastic properties of the subsurface, especially the shear modulus, this also means that seismic velocities will change when the subsurface is thawing. Seismic surface waves are particularly sensitive to changes in shear-wave velocity, and thawing of even very thin layers is reflected by changes in the dispersion characteristics of the surface waves.

We have acquired seismic data in Adventdalen on Svalbard during several field seasons using a variety of seismic sources, including detonating cord, firecrackers, sledgehammer and ambient noise. Vertical geophones record Rayleigh surface waves. We want to use these data to investigate how surface seismic data change with time in warming terrestrial Arctic environments. Thawing in the uppermost sediments usually affects high frequencies, but we here observe variation with time even at frequencies <50 Hz, likely related to higher modes of Rayleigh waves. We observe an inversely dispersive trend in frequency-velocity (F-V) spectra of seismic records from winter, while this trend is absent from summer records. The inversely dispersive trend does not correspond with the theoretical dispersion curve of a single mode of surface waves, but is instead likely caused by interference between several higher modes of surface waves. Separation of the individual modes is difficult in F-V spectra, especially when the seismic records contain a significant amount of noise. Inversion of surface wave data with higher modes is therefore not straightforward and requires further attention. Through seismic modeling of various geological models and subsequent extraction of Rayleigh wave dispersion curves from the synthetic seismograms, we find that a large number of higher modes like we see here is typical for models with irregular velocity gradients, which may be caused by variation in geology or pore-water salinity with depth.

Authors:

Helene Meling Stemland, University of Bergen
Tor Arne Johansen, University of Bergen & The University Center in Svalbard
Bent Ole Ruud, University of Bergen

Thu 10:50 - 11:10

“From sound source to perception: seismic surveys and cetacean hearing.”

Hannah Kriesell, Norwegian University of Science and Technology

Abstract:

Several biological
studies have focused on the impacts of airgun blasts during seismic acquisition
on cetaceans and have described avoidance behaviour, changes in vocalisation
rates and auditory masking effects. Apart from few exceptions, the work mainly focused
on behavioural responses based on visual observations or experimentally
acquired hearing thresholds or temporary threshold shifts. Meanwhile, recent geophysical
studies provide new insights into physical aspects of seismic sound generation
and propagation, e.g. the emission of high frequencies (> 5kHz) resulting
from ghost cavitation (Khodabandeloo and Landrø 2017) and frequency-dependent amplitudes of air gun arrays
fired at long distances (10-100 km) with increasing water depth (Dao and Landrø 2017). There is little overlap between biological and
geophysical studies. Environmental impact studies have addressed the effect of
seismic surveys on marine life without necessarily understanding or considering
the physical and technical principles applied during seismic acquisition.
Reversely, geophysical research has been mostly focused on increased efficiency
and data quality and less on how seismic shooting impacts marine life. We argue
that in order to be able to evaluate the effects of airgun shooting on
cetaceans, we need to expand and combine our knowledge about the seismic acoustic
output, i.e. how the seismic signal is modified as it is coupled with the
medium water, propagates through this medium and is subsequently coupled with
the sensory organs of the receiver.

Specifically, we want to
model acoustic absorption, geometrical spreading and the relaxation effect of acoustic
signals produced during a seismic test survey that was conducted in 2008. The
water depth was approximately 55 m, and a single hydrophone was permanently
placed at the seabed. The shooting vessel was equipped with three conventional
air gun subarrays, and several shot lines crossing vertically above the
hydrophone were acquired. Single guns, gun clusters, and several configurations
using full array, single subarrays and various configurations were tested. The
maximum acquisition frequency was 62.5 kHz and typically 40-50 shots were
acquired for each shot line. We will use these measurements to first back off
the absorption effects from the source to the sea-bottom hydrophone and
subsequently add absorption and geometrical spreading effects at various
distances from the source array. The resulting information is combined with audiograms of cetacean species
taken from the literature to predict the audibility of the seismic shooting for
those species as a function of frequency and distance between receiver (the
animal) and the sound source (the airgun or airgun array).

Author:

Hannah Kriesell, Norwegian University of Science and Technology
Martin Landrø, Norwegian University of Science and Technology

Thu 11:10 - 11:30

“Different aspects of detection of karstified reservoirs – case examples from gravimetry and seismic interpretation.”

Terje Solbakk, Norwegian University of Science and Technology

Abstract:

Here, we present three different case scenarios highlighting different aspects of identifying karstified reservoirs. Karstified carbonates are emerging as a new play model on the Norwegian shelf, ref 7120/1-3 ‘Gohta’ and 7220/11-1 ‘Alta’ discoveries where karstification enhanced the reservoir properties. The first case scenario focuses on the use of microgravimetry in an onshore setting. Open cave passages and other karst features form negative density contrasts expressed in gravity field anomalies. With the aid of 3D forward modelling of surface gravity measurements, we investigated a large karst cave complex, known as the Svarthammarhola cave, in the Caledonian nappe setting of Nordland. Distinct gravity lows detected in the gravity survey were interpreted as previously unknown and inaccessible cave rooms, substantially expanding the overall Svarthammarhola cave volume. Our results also have wider implications on how gravity field data can be used for the understanding of complex subsurface karst features. We present an interpretation approach for microgravimetry, applicable for challenging geological settings with heterogeneous lithologies. The results were published in Norwegian Journal of Geology in November 2018.
Our second case scenario addresses the identification of karst elements and karst landforms on seismic data. Such identification is a function of size distribution, seismic resolution and the issue of ruling out isomorphs – similar non-karst landforms with another genesis giving the same seismic expression. Thus, when it comes to identifying karst features on seismic, identification will be made on secondary observations, indicative but not conclusive evidence for karst features. Other plausible explanations for the same seismo-morphological features must be taken into consideration when assessing paleokarst in the subsurface. We present interpretations from the Loppa High of the Barents Sea, where we identified two regions – one with clear karst identification on seismic supported by secondary arguments and one with more equivocal interpretations where alternative models may be valid. The implication of these alternative karst models for exploration studies is significant - especially if expected karst-related high porosity zones are in fact absent. To be submitted.
In the 3rd case scenario we compare settings of karst morphology onshore Norway with karstifiable rocks of the stratigraphic record of the Norwegian Continental Shelf. Karst morphologies, such as caves and dolines are common elements of the carbonates onshore Norway. The aim is to get an overview of where to possibly find karstified reservoirs buried on the Norwegian shelf, and what kind of karst one might expect to find in these offshore, submerged settings. In prep.

Authors:

Terje Solbakk, Norwegian University of Science and Technology
Christine Fichler, Norwegian University of Science and Technology
Tore Amund Svånå
Walter Wheeler, NORCE Research (Energy)
Philip Ringrose, Norwegian University of Science and Technology
Stein-Erik Lauritzen, University of Bergen

Thu 11:30 - 11:50

11:50-12:50 Lunch

12:50 - 13:40 Session 9

"The seismic Imaging challenge of the Barents Sea; from the quaternary down to the lower crust."

Jan Erik Lie, Lundin Norway

Thu 12:50 - 13:10

"New ways to enhance the low frequency signal from air gun arrays."

Martin Landrø, NTNU

Abstract:

Over the past decade there has been significant improvements in seismic acquisition with respect to achieving a broader and richer frequency spectrum of the data. The importance of enhancing frequencies below 5 Hz has been of particular interest since it improves conventional data and full waveform inversion results. The frequency content of the air gun is mainly controlled by its depth and the volume. Especially for frequencies less than 5 Hz, the source depth dependency is not so well understood. Hence, we have done experiments, both in a large water tank in the laboratory, and field experiments in a fjord to investigate how the source depth impacts the low frequency content in a seismic experiment. We conduct dedicated tank experiments to investigate the changes of the source signal for very shallow sources in more detail. A small-volume air gun is fired at different distances from the water-air interface, including depths for which the air bubble bursts directly into the surrounding air. The variations of the oscillating bubble and surface disturbances, which can cause changes of the reflected signal from the sea surface, are explored to determine whether an increased frequency signal below 5 Hz can be achieved from very shallow air guns. The results are compared with field measurements of a large-volume air gun fired close to the sea surface. The results reveal an increased signal for frequencies below 5 Hz of up to 10 and 20 dB for the tank and field experiments, respectively, for the source depth at which the air gun bubble bursts directly into the surrounding air. For large-volume air guns, an increased low frequency signal might also be achieved for sources that are slightly deeper than this bursting depth.

Authors:

Martin Landrø, NTNU
Daniel Wehner, NTNU
Lasse Amundsen, NTNU/Equinor

Thu 13:10 - 13:30

Closing remarks

Alfred Hanssen

Thu 13:30 - 13:40

Transportation.

14:00 -15:15 Bus to Tromsø (airport, city centre and UiT)

 

 

The schedule at a glance

 

Practical information

Time

Tuesday 22 October – Thursday 24 October, 2019.
Add to your calendar.

Registration

Please register via the online registration form: https://arcex.no/arcex-2019-registration/

Once successfully registered, you should receive a confirmation email.

If you do not receive a confirmation email, please check your spam filter, or look for your name in the list of participants.

If you need to cancel or make any changes to your registration, you can do so either via the link provided in the email you receive upon registering, or by sending us an email and we will help you, ellen.i.hatta@uit.no.

Venue

Sommarøy Arctic Hotel, Sommarøy, Tromsø.

Sommarøy is located at the western part of Tromsø Municipality, 52 km from Tromsø Airport. The journey is a scenic drive, through fjords and mountains for about 50 minutes.

  • Address: Skipsholmveien 22, 9110 Sommarøy
  • Telephone: +47 77 66 40 00
  • E-mail: resepsjon@sommaroy.no

Accommodation

The cost of accommodation at Sommarøy Arctic Hotel is:

  • Single room, NOK 1175 per person per night
  • Shared room, NOK 795 per person per night

The accommodation provided is a mix of hotel rooms and apartment/cabins. All rooms have private bathrooms. Breakfast is included.

Please note that accommodation costs are covered by the participants, and should be paid directly to the hotel upon check-in.

The reservation is handled as a group booking, and you reserve your room via the registration form. You will not receive a separate confirmation from the hotel. If you have any questions or requests regarding your room, please contact ellen.i.hatta@uit.no.

Transportation

We will provide bus transportation from UiT, city centre/Prostneset and Tromsø airport to Sommarøy Arctic Hotel on Tuesday and back to Tromsø on Thursday. Estimated arrival time at Tromsø airport is 15:00.

Registration fee

There is no registration fee. Conference meals and bus transportation Tromsø-Sommarøy are free of charge for participants from the ARCEx consortium.

Travel to and from Tromsø, and cost of accommodation are covered by the participants.

Cancellations

Last cancellation date: 9 September 2019.  Cancellations after this date will be charged for the cost of accommodation.

If you need to cancel or make any changes to your registration, you can do so either via the link provided in the email you receive upon registering, or by sending us an email and we will help you, ellen.i.hatta@uit.no.

 

Contact

Prof. Alfred Hanssen, ARCEx Director, mobile +47 452 55 593, alfred.hanssen@uit.no

Ellen Ingeborg Hætta, Administrative leader ARCEx, mobile +47 988 01 001, ellen.i.hatta@uit.no