| 1. |
- Aleklett, Kjell, et al.
(författare)
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The Peak of the Oil Age : Analyzing the world oil production Reference Scenario in World Energy Outlook 2008
- 2010
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Ingår i: Energy Policy. - Oxford : Elsevier Ltd. - 0301-4215 .- 1873-6777. ; 38:3, s. 1398-1414
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Tidskriftsartikel (refereegranskat)abstract
- The assessment of future global oil production presented in the IEA’s World Energy Outlook 2008 (WEO 2008) is divided in to 6 fractions; four relate to crude oil, one to non-conventional oil, and the final fraction is natural-gas-liquids (NGL). Using the production parameter, depletion-rate-of-recoverable- resources, we have analyzed the four crude oil fractions and found that the 75 Mb/d of crude oil production forecast for year 2030 appears significantly overstated, and is more likely to be in the region of 55 Mb/d. Moreover, an alysis of the other fractions strongly suggests lower than expected production levels. In total, our analysis points to a world oil supply in 2030 of 75Mb/d, some 26 Mb/d lower than the IEA predicts. The connection between economic growth and energy use is fundamental in the IEA’s present modeling approach. Since our forecast sees little chance of a significant increase in global oil production, our findings suggest that the ‘‘policy makers, investors and end users’’ to whom WEO 2008 is addressed should rethink their future plans for economic growth. The fact that global oil production has very probably passed its maximum implies that we have reached the Peak of the Oil Age.
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| 2. |
- Bjerså, Kristofer, et al.
(författare)
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Adjunct High Frequency Transcutaneous Electric Stimulation (TENS) for Postoperative Pain Management during Weaning from Epidural Analgesia Following Colon Surgery: Results from a Controlled Pilot Study.
- 2015
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Ingår i: Pain management nursing : official journal of the American Society of Pain Management Nurses. - : Elsevier BV. - 1532-8635 .- 1524-9042. ; 16:6, s. 944-950
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Tidskriftsartikel (refereegranskat)abstract
- The potential benefit of nonpharmacological adjunctive therapy is not well-studied following major abdominal surgery. The aim of the present study was to investigate transcutaneous electrical nerve stimulation (TENS) as a complementary nonpharmacological analgesia intervention during weaning from epidural analgesia (EDA) after open lower abdominal surgery. Patients were randomized to TENS and sham TENS during weaning from EDA. The effects on pain at rest, following short walk, and after deep breath were assessed by visual analog scale (VAS) grading. Number of patients assessed was lower than calculated because of change in clinical routine. Pain scores overall were low. A trend of lower pain scores was observed in the active TENS group of patients; a statistical significance between the groups was found for the pain lying prone in bed (p<.05). This controlled pilot study indicate benefits of TENS use in postoperative pain management during weaning from EDA after open colon surgery. Further studies are warranted in order to verify the potential beneficial effects from TENS during weaning from EDA after open, lower abdominal surgery.
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| 3. |
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| 4. |
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| 5. |
- Höök, Mikael, 1982-, et al.
(författare)
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The evolution of giant oil field production behaviour
- 2009
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Ingår i: Natural Resources Research. - : Springer Science and Business Media LLC. - 1520-7439 .- 1573-8981. ; 18:1, s. 39-56
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Tidskriftsartikel (refereegranskat)abstract
- The giant oil fields of the world are only a small fraction of the total number of fields, but their importance is huge. Over 50% of the world oil production came from giants by 2005 and more than haft of the worlds ultimate reserves are found in giants. Based on this it is reasonable to assume that the future development of the giant oil fields will have a significant impact on the world oil supply. In order to better understand the giant fields and their future behaviour one must first understand their history. This study has used a comprehensive database on giant oil fields in order to determine their typical parameters, such as the average decline rate and life-times of giants. The evolution of giant oil field behaviour has been investigated to better understand future behaviour. One conclusion is that new technology and production methods have generally lead to high depletion rate and rapid decline. The historical trend points towards high decline rates of fields currently on plateau production. The peak production generally occurs before half the ultimate reserves have been produced in giant oil fields. A strong correlation between depletion-at-peak and average decline rate is also found, verifying that high depletion rate leads to rapid decline. Our result also implies that depletion analysis can be used to rule out unrealistic production expectations from a known reserve, or to connect an estimated production level to a needed reserve base.
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| 6. |
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| 7. |
- Jakobsson, Kristofer, et al.
(författare)
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Bottom-up modeling of oil production : A review of approaches
- 2014
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Ingår i: Energy Policy. - : Elsevier BV. - 0301-4215 .- 1873-6777. ; 64, s. 113-123
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Forskningsöversikt (refereegranskat)abstract
- Bottom-up models of oil production are continuously being used to guide investments and policymaking. Compared to simpler top-down models, bottom-up models have a number of advantages due to their modularity, flexibility and concreteness. The purposes of this paper is to identify the crucial modeling challenges, compare the different ways in which nine existing models handle them, assess the appropriateness of these models, and point to possibilities of further development. The conclusions are that the high level of detail in bottom-up models is of questionable value for predictive accuracy, but of great value for identifying areas of uncertainty and new research questions. There is a potential for improved qualitative insights through systematic sensitivity analysis. This potential is at present largely unrealized.
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| 8. |
- Jakobsson, Kristofer, et al.
(författare)
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How reasonable are oil production scenarios from public agencies?
- 2009
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Ingår i: Energy Policy. - : Elsevier BV. - 0301-4215 .- 1873-6777. ; 37:11, s. 4809-4818
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Tidskriftsartikel (refereegranskat)abstract
- According to the long term scenarios of the International Energy Agency (IEA) and the U.S. Energy Information Administration (EIA), conventional oil production is expected to grow until at least 2030. EIA has published results from a resource constrained production model which ostensibly supports such a scenario. The model is here described and analyzed in detail. However, it is shown that the model, although sound in principle, has been misapplied due to a confusion of resource categories. A correction of this methodological error reveals that EIA’s scenario requires rather extreme and implausible assumptions regarding future global decline rates. This result puts into question the basis for the conclusion that global "peak oil" would not occur before 2030.
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| 9. |
- Jakobsson, Kristofer, 1982-
(författare)
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Modeling Oil Exploration and Production : Resource-Constrained and Agent-Based Approaches
- 2010
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Energy is essential to the functioning of society, and oil is the single largest commercial energy source. Some analysts have concluded that the peak in oil production is soon about to happen on the global scale, while others disagree. Such incompatible views can persist because the issue of “peak oil” cuts through the established scientific disciplines. The question is: what characterizes the modeling approaches that are available today, and how can they be further developed to improve a trans-disciplinary understanding of oil depletion? The objective of this thesis is to present long-term scenarios of oil production (Paper I) using a resource-constrained model; and an agent-based model of the oil exploration process (Paper II). It is also an objective to assess the strengths, limitations, and future development potentials of resource-constrained modeling, analytical economic modeling, and agent-based modeling. Resource-constrained models are only suitable when the time frame is measured in decades, but they can give a rough indication of which production scenarios are reasonable given the size of the resource. However, the models are comprehensible, transparent and the only feasible long-term forecasting tools at present. It is certainly possible to distinguish between reasonable scenarios, based on historically observed parameter values, and unreasonable scenarios with parameter values obtained through flawed analogy. The economic subfield of optimal depletion theory is founded on the notion of rational economic agents, and there is a causal relation between decisions made at the micro-level and the macro-result. In terms of future improvements, however, the analytical form considerably restricts the versatility of the approach. Agent-based modeling makes it feasible to combine economically motivated agents with a physical environment. An example relating to oil exploration is given in Paper II, where it is shown that the exploratory activities of individual agents can yield a U-shaped exploration cost path. Agent-based modeling appears to have significant potential for future development, but it is still unclear whether it will be the most useful in policy evaluation or more generalized systems research.
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| 10. |
- Jakobsson, Kristofer, et al.
(författare)
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Oil exploration and perceptions of scarcity : The fallacy of early success
- 2012
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Ingår i: Energy Economics. - : Elsevier BV. - 0140-9883 .- 1873-6181. ; 34:4, s. 1226-1233
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Tidskriftsartikel (refereegranskat)abstract
- It has been suggested that oil exploration may lead to false perceptions of decreasing scarcity. We perform a simulation of the exploration process using Bayesian updating. The approach enables us to isolate the information effect on the success rate and also to quantify the subjective expectation of the total resource size. The area under exploration consists of a number of regions which may differ in their oil content. Exploration is performed with the goal to maximize the expected success rate. The resulting information about the distribution of oil and the total resource size is assumed public knowledge. A number of scenarios with variations in the dimensions of the area under exploration, the oil distribution and initial beliefs are considered. The results indicate that the information effect on the success rate is significant but brief — it might have a considerable impact on price but is an unlikely mechanism behind a long-term declining price trend. However, the information effect on expectations is gradual and persistent. Since exploration is performed in regions where the expected success rate is the highest, the historical success rate will not be representative of the area as a whole. An explorer will tend to overestimate the total resource size, thereby suggesting an alternative mechanism for false perceptions of decreasing scarcity, a mechanism that could be called the “fallacy of early success”.
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| 11. |
- Jakobsson, Kristofer
(författare)
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Petroleum Production and Exploration : Approaching the End of Cheap Oil with Bottom-Up Modeling
- 2012
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The theme of this thesis is the depletion of petroleum (crude oil and natural gas). Are there reasons to be concerned about an ‘end of cheap oil’ in the near future? There is a lively debate regarding this issue. The debate is sometimes described as a clash of ‘concerned’ natural scientists and ‘unconcerned’ economists. However, this clash is both harmful and unnecessary. The views of natural scientists and economists can and should be reconciled. At the micro-level, geological and physical factors (such as diminishing reservoir productivity) are parameters in the producer’s economic optimization problem. Bottom-up modeling therefore appears to hold more promise for forming a common understanding of depletion than prevailing top-down models, such as the controversial Hubbert model. The appended papers treat various aspects of petroleum depletion: critical examination of top-down scenarios (I); bottom-up economic and geologic modeling of regional production (II); review of published bottom-up models and sensitivity analysis (III); simulation of success rates and expectations in oil exploration (IV); bottom-up scenarios of future natural gas production in Norway (V) and Russia (VI); empirical analysis of production profiles of giant oil fields (VII). Bottom-up models have the potential to be accepted by scientists from different disciplines, and they enable interpretable sensitivity analyses. They are, however, not likely to reduce quantitative uncertainty in long-term scenarios. There is theoretical evidence of the possibility that petroleum scarcity occurs long before the recoverable resource is close to exhaustion. This result is a consequence of both geological and economical factors. Several arguments for an ‘unconcerned’ view are at best uncertain, and at worst relying on questionable assumptions (analyzing reserves rather than production flows, using irrelevant reserve definitions, using average cost instead of marginal cost). The considerable uncertainty regarding an issue of such importance is in itself a cause for concern.
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| 12. |
- Jakobsson, Kristofer, et al.
(författare)
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The end of cheap oil : Bottom-up economic and geologic modeling of aggregate oil production curves
- 2012
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Ingår i: Energy Policy. - : Elsevier BV. - 0301-4215 .- 1873-6777. ; 41, s. 860-870
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Tidskriftsartikel (refereegranskat)abstract
- There is a lively debate between 'concerned' and 'unconcerned' analysts regarding the future availability and affordability of oil. We critically examine two interrelated and seemingly plausible arguments for an unconcerned view: (1) there is a growing amount of remaining reserves: (2) there is a large amount of oil with a relatively low average production cost. These statements are unconvincing on both theoretical and empirical grounds. Oil availability is about flows rather than stocks, and average cost is not relevant in the determination of price and output. We subsequently implement a bottom-up model of regional oil production with micro-foundations in both natural science and economics. An oil producer optimizes net present value under the constraints of reservoir dynamics, technological capacity and economic circumstances. Optimal production profiles for different reservoir drives and economic scenarios are derived. The field model is then combined with a discovery model of random sampling from a lognormal field size-frequency distribution. Regional discovery and production scenarios are generated. Our approach does not rely on the simple assumptions of top-down models such as the Hubbert curve - however it leads to the same qualitative result that production peaks when a substantial fraction of the recoverable resource remains in-ground.
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| 13. |
- Söderbergh, Bengt, 1975-, et al.
(författare)
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European energy security : The future of Norwegian natural gas production
- 2009
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Ingår i: Energy Policy. - Oxford : Elsevier Limited. - 0301-4215 .- 1873-6777. ; 37:12, s. 5037-5055
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Tidskriftsartikel (refereegranskat)abstract
- The European Union (EU) is expected to meet its future growing demand for natural gas by increased imports. In 2006, Norway had a 21% share of EU gas imports. The Norwegian government has communicated that Norwegian gas production will increase by 25–40% from today’s level of about 99 billion cubic meters (bcm)/year. This article shows that only a 20–25% growth of Norwegian gas production is possible due to production from currently existing recoverable reserves and contingent resources. A high and a low production forecast for Norwegian gas production is presented. Norwegian gas production exported by pipeline peaks between 2015 and 2016, with minimum peak production in 2015 at 118 bcm/year and maximum peak production at 127 bcm/year in 2016. By 2030 the pipeline Export levels are 94–78 bcm. Total Norwegian gas production peaks between 2015 and 2020, with peak production at 124–135 bcm/year. By 2030 the production is 96–115 bcm/year. The results show that there is a limited potential for increased gas exports from Norway to the EU and that Norwegian gas production is declining by 2030 in all scenarios. Annual Norwegian pipeline gas exports to the EU, by 2030, may even be 20 bcm lower than today’s level.
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| 14. |
- Söderbergh, Bengt, 1975-, et al.
(författare)
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European energy security : An analysis of future Russian natural gas production and exports
- 2010
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Ingår i: Energy Policy. - : Elsevier BV. - 0301-4215 .- 1873-6777. ; 38:12, s. 7827-7843
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Tidskriftsartikel (refereegranskat)abstract
- The widening gap between EU gas production and consumption may require an 87% increase of import volumes between 2006 and 2030, and there are great uncertainties regarding the amounts of gas that can be expected from new suppliers. The potential of increased production from Norway and Algeria is limited, hence, Russia is likely to play a crucial part of meeting the anticipated growing gas demand of the EU. A field-by-field study of 83 giant gas fields shows that the major producing Russian gas fields are in decline, and by 2013 much larger supplies from the Yamal Peninsula and the Shtokman field will be needed in order to avoid a decline in production. Gas from fields in Eastern Siberia and the Far East will mainly be directed to the Asian and Pacific Rim markets, thereby limiting its relevance to the European and CIS markets. As a result, the maximum export increase to the European and CIS markets amounts only to about 45% for the period 2015-2030. The discourse surrounding the EU’s dependence on Russian gas should thus not only be concerned with geopolitics, but also with the issue of resource limitations.
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| 15. |
- Thompson, Bijoy, et al.
(författare)
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A model study of the first ventilated regime of the Arctic Ocean during the early Miocene
- 2012
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Ingår i: Polar Research. - : Norwegian Polar Institute. - 0800-0395 .- 1751-8369. ; 31, s. 10859-
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Tidskriftsartikel (refereegranskat)abstract
- The tectonic opening of Fram Strait during the Neogene was a significant geological event that transferred the Arctic Ocean from a poorly ventilated enclosed basin, with weak exchange with the North Atlantic, to a fully ventilated ocean stage''. Previous tectonic and physical oceanographic analyses suggest that the early Miocene Fram Strait was likely several times narrower and less than half as deep as the present-day 400 km wide and 2550 m deep strait. Here we use an ocean general circulation model with a passive age tracer included to further address the effect of the Fram Strait opening on the early Miocene Arctic Ocean circulation. The model tracer age exhibits strong spatial gradient between the two major Arctic Ocean deep basins: the Eurasian and Amerasian basins. There is a two-layer stratification and the exchange flow through Fram Strait shows a bi-layer structure with a low salinity outflow from the Arctic confined to a relatively thin upper layer and a saline inflow from the North Atlantic below. Our study suggests that although Fram Strait was significantly narrower and shallower during early Miocene, and the ventilation mechanism quite different in our model, the estimated ventilation rates are comparable to the chemical tracer estimates in the present-day Arctic Ocean. Since we achieved ventilation of the Arctic Ocean with a prescribed Fram Strait width of 100 km and sill depth of 1000 m, ventilation may have preceded the timing of a full ocean depth connection between the Arctic Ocean and North Atlantic established through seafloor spreading and the development of the Lena Trough.
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| 16. |
- Thompson, Bijoy, et al.
(författare)
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Estimating ventilation time scales using overturning stream functions
- 2014
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Ingår i: Ocean Dynamics. - : Springer Science and Business Media LLC. - 1616-7341 .- 1616-7228. ; 64:6, s. 797-807
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Tidskriftsartikel (refereegranskat)abstract
- A simple method for estimating ventilation time scales from overturning stream functions is proposed. The stream function may be computed using either geometric coordinates or a generalized vertical coordinate, such as potential density (salinity in our study). The method is tested with a three-dimensional circulation model describing an idealized semi-enclosed ocean basin ventilated through a narrow strait over a sill, and the result is compared to age estimates obtained from a passive numerical age tracer. The best result is obtained when using the stream function in salinity coordinates. In this case, the reservoir-averaged advection time obtained from the overturning stream function in salinity coordinates agrees rather well with the mean age of the age tracer, and the corresponding maximum ages agree very well.
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| 17. |
- Thompson, Bijoy, et al.
(författare)
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Ventilation of the Miocene Arctic Ocean : An idealized model study
- 2010
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Ingår i: Paleoceanography. - 0883-8305 .- 1944-9186. ; 25, s. PA4216-
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Tidskriftsartikel (refereegranskat)abstract
- A model study of an idealized early Miocene Arctic Ocean has been undertaken. The work is motivated by the first drill core retrieved from the Lomonosov Ridge in the central Arctic Ocean, which suggests a transition from anoxic to oxic condition during the early Miocene, a feature presumably related to the opening of the Fram Strait. Here, the ventilation in a semienclosed basin, connected with the ocean through a strait with a sill, is examined using an ocean circulation model that includes a passive age tracer. In particular, we investigate how the ventilation depends on strait geometry, freshwater influx, and surface wind stress. We find that the turnover time, characterizing the bulk ventilation rate, is primarily controlled by the strait width and the wind stress. Generally, the oldest water in the basin is encountered near the sill depth, but wind forcing displaces the oldest water downward. For narrow straits, the turnover time gives an upper bound on the mean age of the basin water. The results have implications when translating local oxygen conditions, recorded in the sediment sequence from the Lomonosov Ridge, to basin-scale circulation patterns. Further, the results indicate that the early Miocene Arctic Ocean became well ventilated when the Fram Strait reached a width of about 100 km.
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