Report on Optimization of Seafloor Deployments for Permanent Reservoir Monitoring

This report addresses how distributed fibre-optic sensing can be used for monitoring of CO2 storage processes, and more specifically how it compares to conventional seismic data. It focusses on shallow subsurface characterization (uppermost 100 m below seabed), and high resolution and high frequency seismic data. Our main conclusion is that distributed acoustic sensing in our experiment gives comparable results to those obtained from shallow seismic methods

CO2 saturation and thickness predictions in the Tubåen Fm., Snøhvit field, from analytical solution and time-lapse seismic data

CO2 migration in a saline aquifer is governed by viscous, capillary and gravitational fluid forces at an early stage of injection, where the dominant flow regime is site specific and controls the fluid migration in the pore space. This study combines the CO2 saturation inverted from time-lapse seismic methods with an analytical expression to define the CO2 flow regime, saturation distribution and layer thickness in the Tubåen Fm. following CO2 injection. Quantitative estimates of the CO2 saturation from time-lapse seismic amplitude versus offset (AVO) and spectral decomposition are compared to a viscous dominated analytical expression of CO2 injection into a saline aquifer. The spatial extent of the CO2 plume obtained from time-lapse spectral decomposition and inverted from time-lapse AVO analysis display good agreement with the analytical expression. The CO2 is limited to an area close to the injection well, with an elongated shape in the channel direction. Comparison between the time-lapse seismic and analytical expression shows that the fluid flow is dominated by viscous forces. CO2 saturation within the plume is constant and close to the residual brine saturation. The influence of gravity is ignorable on the reservoir CO2 flow. CO2 fills the entire sandstone unit up to approximately 50 m away from the injection before the CO2 layer thickness is reduced to a thin wedge that propagates below the overlying shale unit. Reduction in CO2 saturation away from the injection well is a reduction in effective CO2 saturation relative to the thickness of the horizon. The maximum radius of the CO2 layer from the analytic expression is 750 m, of which 400 m is above the time-lapse noise level. Time-lapse seismic analysis reveals the CO2 layer radius is 405 m in the direction of the local fluvial channel and 273 m in the perpendicular direction

Utilizing spectral decomposition to determine the distribution of injected CO2 at the Snøhvit Field

Time-lapse 3D seismic reflection data, covering the CO2 storage operation at the Snøhvit gas field in the Barents Sea, show clear amplitude and time-delay differences following injection. The nature and extent of these changes suggest that increased pore fluid pressure contributes to the observed seismic response, in addition to a saturation effect. Spectral decomposition using the smoothed pseudo-Wigner–Ville distribution has been used to derive discrete-frequency reflection amplitudes from around the base of the CO2 storage reservoir. These are utilized to determine the lateral variation in peak tuning frequency across the seismic anomaly as this provides a direct proxy for the thickness of the causative feature. Under the assumption that the lateral and vertical extents of the respective saturation and pressure changes following CO2 injection will be significantly different, discrete spectral amplitudes are used to distinguish between the two effects. A clear spatial separation is observed in the distribution of low- and high-frequency tuning. This is used to discriminate between direct fluid substitution of CO2, as a thin layer, and pressure changes that are distributed across a greater thickness of the storage reservoir. The results reveal a striking correlation with findings derived from pressure and saturation discrimination algorithms based on amplitude versus offset analysis

Foreldresamarbeid og digitale verktøy

Problemstilling: Hvordan kan bruken av digitale verktøy i pedagogisk dokumentasjon styrke relasjonen mellom barnehage og hjem?bachelor-v201

Sammenhengen mellom problematisk dataspilling og selvmordsatferd – En systematisk litteraturgjennomgang

Hovedoppgave psykologprogrammetPROPSY317PRPSY

Burying receivers for improved time-lapse seismic repeatability: CO2CRC Otway field experiment

4D seismic is widely used to remotely monitor fluid movement in subsurface reservoirs. This technique is especially effective offshore where high survey repeatability can be achieved. It comes as no surprise that the first 4D seismic that successfully monitored the CO2 sequestration process was recorded offshore in the Sleipner field, North Sea. In the case of land projects, poor repeatability of the land seismic data due to low S/N ratio often obscures the time-lapse seismic signal. Hence for a successful on shore monitoring program improving seismic repeatability is essential. Stage 2 of the CO2CRC Otway project involves an injection of a small amount (around 15,000 tonnes) of CO2/CH4 gas mixture into a saline aquifer at a depth of approximately 1.5 km. Previous studies at this site showed that seismic repeatability is relatively low due to variations in weather conditions, near surface geology and farming activities. In order to improve time-lapse seismic monitoring capabilities, a permanent receiver array can be utilised to improve signal to noise ratio and hence repeatability.A small-scale trial of such an array was conducted at the Otway site in June 2012. A set of 25 geophones was installed in 3 m deep boreholes in parallel to the same number of surface geophones. In addition, four geophones were placed into boreholes of 1–12 m depth. In order to assess the gain in the signal-to-noise ratio and repeatability, both active and passive seismic surveys were carried out. The surveys were conducted in relatively poor weather conditions, with rain, strong wind and thunderstorms. With such an amplified background noise level, we found that the noise level for buried geophones is on average 20 dB lower compared to the surface geophones. The levels of repeatability for borehole geophones estimated around direct wave, reflected wave and ground roll are twice as high as for the surface geophones. Both borehole and surface geophones produce the best repeatability in the 30–90 Hz frequency range. The influence of burying depth on S/N ratio and repeatability shows that significant improvement in repeatability can be reached at a depth of 3 m. The level of repeatability remains relatively constant between 3 and 12 m depths

The effect of attentional bias modification on positive affect dynamics

Negative attentional bias and alterations in positive affect dynamics constitute emotional vulnerability to depression. Attentional bias modification (ABM) aims to reduce emotional vulnerability to depression by fostering attentional deployment towards positive stimuli. In this randomized controlled trial, we examined whether ABM leads to changes in positive affect dynamics in a sample with an emotional vulnerability to depression (N = 65). Affect dynamics were measured based on experience sampling data gathered 14 days before and after ABM. During ABM, participants paid attention to pairs of emotional faces and responded to dots that were appearing in their place. There was an 87% chance for the dots to appear in place of the relatively more positive face, with the purpose to implicitly foster attentional focus on positive stimuli. In the control condition, there was a 50% chance of the dots to appear in place of the positive stimuli. Results showed that the lag-1 autocorrelation of affect (“inertia”) increased within the ABM group and decreased in the control group, but the findings were not robust and it was unclear whether ABM was the cause. There were no changes in the other affect dynamics indices. Improvements in depression during ABM were not associated with changes in affect dynamics, and affect dynamics post ABM did not predict depression symptoms six months later. In conclusion, the study showed no clear effect of ABM on affect dynamics

Developing and evaluating cognitive remediation therapy (CRT) for adolescents with anorexia nervosa: A feasibility study

Background: Cognitive Remediation Therapy (CRT) aims at improving neuropsychological weaknesses and associated thinking styles in patients with anorexia nervosa (AN). It has only recently been developed for adolescents with AN, and evidence of its applicability for this particular patient group is limited. This study aimed to test the feasibility of individually tailored and delivered CRT for young females with AN. Methods: A sample of 20 in- and outpatients (13–18 years) with AN participated in once- or twice weekly individual CRT sessions. The CRT materials used were available in a “CRT Resource Pack.” Feasibility was assessed with regards to the recruitment process, the delivery of the intervention, the materials used and clinical experiences. Results: Overall results indicate that the intervention was feasible with regards to (a) the recruitment of both in- and outpatients, (b) individual tailoring and delivery, (c) the CRT materials adapted to suit young females with AN, and (d) the acceptability for clinicians involved in the study. There were no voluntary dropouts, with 19 of 20 patients completing the entire course of treatment. Conclusions: The findings have implications for the refinement of CRT for the youngest AN population, and strengthens our understanding of the core components in the development and evaluation of novel interventions targeting AN. This study will help inform the design of a subsequent randomized controlled trial. © The Author(s) 2013. Published by SAGE Publications

Communicating public avalanche warnings – what works?

Like many other mountainous countries, Norway has experienced a rapid increase in both recreational winter activities and fatalities in avalanche terrain during the past few decades: during the decade 2008–2017, 64 recreational avalanche fatalities were recorded in Norway. This is a 106&thinsp;% increase from that of the previous decade. In 2013, Norway therefore launched the National Avalanche Warning Service (NAWS), which provides avalanche warnings to transport and preparedness authorities and to the public. Previous studies suggest that avalanche warnings are used extensively in trip and preparedness planning and have a relatively strong influence on the decisions people make in order to reduce risk. However, no evaluation concerning how efficiently the warnings are communicated and understood has been done to date in Norway. Avalanche warnings communicate complex natural phenomena with a variable complexity and level of uncertainty about both the future and the present. In order to manage avalanche risk successfully, it is fundamental that the warning message can be understood and translated into practice by a wide range of different user groups. Users with little or no avalanche competence may need simple information to decide when to stay away from avalanche terrain, while professional users may need advanced technical details in order to make their decisions. To evaluate how different modes of communication are understood, and how efficiently the informational content is communicated, we designed and implemented a web-based user survey. The modes of presentation were based on the Varsom.no 2017 version (Varsom.no being the national portal for natural hazard warnings in Norway). We first used a panel of 110 experts from NAWS to answer the survey, and used their answers to establish the indented message of the avalanche warning. We thereafter received responses from 264 users and compared their answers to those of the NAWS experts for the different modes of communication. We developed a method, the comprehension effectiveness score, to test the comprehension. Our empirical analyses suggest that most users find the warning service to be useful and well suited to their needs. However, the effectiveness of a warnings seems to be influenced by the competency of the user and the complexity of the scenarios. We discuss the findings and make recommendations on how to improve communication of avalanche warnings.</p

The role of insomnia in the treatment of chronic fatigue

AbstractBackgroundThe definition of Chronic Fatigue Syndrome (CFS) overlaps with definitions of insomnia, but there is limited knowledge about the role of insomnia in the treatment of chronic fatigue.AimsTo test if improvement of insomnia during treatment of chronic fatigue was associated with improved outcomes on 1) fatigue and 2) cortisol recovery span during a standardized stress exposure.MethodsPatients (n=122) with chronic fatigue received a 3.5-week inpatient return-to-work rehabilitation program based on Acceptance and Commitment Therapy, and had been on paid sick leave>8weeks due their condition. A physician and a psychologist examined the patients, assessed medication use, and SCID-I diagnoses. Patients completed self-report questionnaires measuring fatigue, pain, depression, anxiety, and insomnia before and after treatment. A subgroup (n=25) also completed the Trier Social Stress Test for Groups (TSST-G) before and after treatment. Seven cortisol samples were collected during each test and cortisol spans for the TSST-G were calculated.ResultsA hierarchical regression analysis in nine steps showed that insomnia improvement predicted improvement in fatigue, independently of age, gender, improvement in pain intensity, depression and anxiety. A second hierarchical regression analysis showed that improvement in insomnia significantly predicted the cortisol recovery span after the TSST-G independently of improvement in fatigue.ConclusionImprovement in insomnia severity had a significant impact on both improvement in fatigue and the ability to recover from a stressful situation. Insomnia severity may be a maintaining factor in chronic fatigue and specifically targeting this in treatment could increase treatment response