We present an analysis of oil prices in USD and in other major currencies that diagnoses unsustainable faster-than-exponential behavior. This supports the hypothesis that the recent oil price run-up ...was amplified by speculative behavior of the type found during a bubble-like expansion. We also attempt to unravel the information hidden in the oil supply-demand data reported by two leading agencies, the US Energy Information Administration (EIA) and the International Energy Agency (IEA). We suggest that the found increasing discrepancy between the EIA and IEA figures provides a measure of the estimation errors. Rather than a clear transition to a supply restricted regime, we interpret the discrepancy between the IEA and EIA as a signature of uncertainty, and there is no better fuel than uncertainty to promote speculation! Our post-crash analysis confirms that the oil peak in July 2008 occurred within the expected 80% confidence interval predicted with data available in our pre-crash analysis.
A new method was developed to remove gaseous and particulate pollutants by capturing them in water using microbubbles. The capture efficiency of gaseous toluene and ultrafine carbon particles, which ...are hydrophobic substances, was remarkably improved compared to water-only conditions by adding a small amount of oily substances (4% volume fraction of water) to the water surface. The physicochemical properties of four types of oily substances were investigated. Rapeseed and mineral oil exhibited good capture efficiency during a capture experiment of high-concentration gaseous toluene for 96 h. Additionally, a long-term continuous capture experiment for 24 days revealed that the capture mechanisms of rapeseed and mineral oil were different. The toluene concentration in rapeseed oil reached saturation in the middle of the experiment while the capture efficiency of mineral oil remained constant. It was also shown that the emulsion formation greatly affected the capture of rapeseed oil. Thus, it is expected that a new gaseous pollutant treatment technology that can capture and remove gaseous/particulate pollutants regardless of their hydrophilic/hydrophobic properties could be developed in the future.
•A system for capturing high-concentration VOC gas in water has been established.•The addition of a small amount of oil has greatly improved the capturing efficiency.•Capturing mechanisms tended to differ among different oily substances.•Ultrafine particles were also almost completely captured in water.
The interaction of plasmas sustained in humid air with liquids produces reactive species in both the gas phase and liquid for applications ranging from medicine to agriculture. In several ...experiments, enhanced liquid reactivity has been produced when the liquid is a foam or a bubble coated liquid. To investigate the phenomena of streamers interacting with bubbles a two-dimensional computational investigation has been performed of streamer initiation and propagation on and inside hemispherical bubble-shells floating on a liquid surface. Following prior experiments, water and oil bubble-shells with an electrode located outside and inside the bubble were investigated. We found that positive air streamers interact differently with conductive water and dielectric oil bubbles. The streamer propagates along the external surface of a water bubble while not penetrating through the bubble due to screening of the electric field by the conducting shell. If the electrode is inserted inside the bubble, the path of the streamer depends on how deeply the electrode penetrates. For shallow penetration, the streamer propagates along the inner surface of the bubble. Due to the low conductivity of oil bubble-shells, the electric field from an external electrode penetrates into the interior of the bubble. The streamer can then be re-initiated inside the bubble.
This article examines how the interaction of different participants in the crude oil futures markets affects the crude oil price efficiency. Normally, the commercial market participants, such as oil ...producers and oil consumers, act as arbitrageurs and ensure that the price of crude oil remains within the fundamental value range. However, institutional investors that invest in crude oil to diversify their portfolios and/or hedge inflation can destabilize the interaction among commercial participants and liquidity-providing speculators. We argue that institutional investors can impose limits to arbitrage, particularly during the financial crisis when the investment demand for commodities is particularly strong. In support, we show that commercials hedgers had significantly reduced their short positions leading to the 2008 oil bubble—they were potentially aggressively offsetting their short hedges. As a result, by essentially engaging in a positive feedback trading, commercial hedgers at least contributed to ‘the 2008 oil bubble'. These findings have been mainly overlooked by the existing research.
► This article finds that commercial hedgers at least contributed to the 2008 oil bubble. ► Commercial hedgers were aggressively offsetting their short hedges leading to the oil bubble peak. ► Commercial hedgers, thus, unwillingly engaged in positive feedback trading. ► Institutional investors potentially destabilized the oil markets in 2008.
The transparent open box (TOB) learning network algorithm offers an alternative approach to the lack of transparency provided by most machine-learning algorithms. It provides the exact calculations ...and relationships among the underlying input variables of the datasets to which it is applied. It also has the capability to achieve credible and auditable levels of prediction accuracy to complex, non-linear datasets, typical of those encountered in the oil and gas sector, highlighting the potential for underfitting and overfitting. The algorithm is applied here to predict bubble-point pressure from a published PVT dataset of 166 data records involving four easy-to-measure variables (reservoir temperature, gas-oil ratio, oil gravity, gas density relative to air) with uneven, and in parts, sparse data coverage. The TOB network demonstrates high-prediction accuracy for this complex system, although it predictions applied to the full dataset are outperformed by an artificial neural network (ANN). However, the performance of the TOB algorithm reveals the risk of overfitting in the sparse areas of the dataset and achieves a prediction performance that matches the ANN algorithm where the underlying data population is adequate. The high levels of transparency and its inhibitions to overfitting enable the TOB learning network to provide complementary information about the underlying dataset to that provided by traditional machine learning algorithms. This makes them suitable for application in parallel with neural-network algorithms, to overcome their black-box tendencies, and for benchmarking the prediction performance of other machine learning algorithms.
•Transparent open-box (TOB) algorithm offers a fully auditable prediction tool.•TOB complements neural-network algorithms in its prediction performance.•TOB exploits spreadsheet functions, for example using Excel's Solver optimizers.•TOB's non-linear capabilities provide credible bubble-point pressure predictions.•TOB works less well with sparse data sets, consequently it avoids overfitting issues.
•We design a distributed dual-sensor array for measuring local flow characteristics in emulsions.•We implement an experiment of pipeline flow of emulsions with low velocity and high water-cut.•We ...extract and compare oil bubble size distributions on different positions at the pipe cross section.•We investigate the instability in the motion of bubbles with multi-scale cross entropy.
The scope of the present study is to experimentally investigate the oil bubble size distribution in oil-in-water emulsions. The geometry parameter of a dual-sensor probe is firstly optimized through examining its electrical field distribution and sensitivity. Afterward, an eight-channel distributed dual-sensor probe array is designed for a pipe with 20mm inner diameter (ID) to measure the local holdup, bubble velocity as well as bubble size of the dispersed oil phase in oil-in-water emulsions under low mixture velocity and high water-cut. The results indicate that the changes in mixture velocity and water-cut substantially affect the oil bubble size distribution on different positions at the pipe cross section. With the extraction of the increasing rate regarding multi-scale cross entropy (MSCE) from the fluctuating signals from the leading and rear sensor of the dual-sensor probe, the dynamic instability in the motion of oil bubbles is analyzed. It proves that the multi-scale cross entropy can be an effective indicator on globally characterizing the nonlinear dynamics in oil-in-water emulsions at the pipe cross section.
We argue that “the 2008 Oil Bubble” was directly and indirectly created by the Federal Reserve in response to deflationary risks that resurfaced after the housing bubble burst and the resulting ...credit crisis of 2008. Deflationary risks first appeared after the dot.com bubble burst in 2000 and after the terrorist attacks on September 11, 2001. Manipulation of the US dollar value has been one of the key emergency tools in the Fed’s arsenal. During the entire period from 2000 to 2008, the US dollar has been falling, while the price of crude oil has been rising, with the culmination in July 2008. If other global central banks embrace the Fed’s anti-deflationary strategies, the consequences could be dire for the global economy, potentially resulting in an ultimate gold bubble.
This article addresses the role of world oil price hike of 2007–08 in serving to transform the financial and banking crisis into what is commonly referred to the Great Recession. Existing literature ...on the global crisis of 2007–09 tends to view it as a financial or banking phenomenon, with analyses focusing mainly on state policies, governance mechanisms and market dynamics in transforming the banking crisis of 2007–08 into the economic recession of 2008-12/13 Although often attributing the global meltdown to wider phenomenon of financialisation, rarely do existing perspectives delve into the role of the commodity sector in the global credit crunch. In this paper, we aim to fill this gap, by inquiring into the role played by oil as a financial asset class in the political economy of the global crisis.
•We study the oil price and its effects on the Great Recession.•We approach oil as a financial asset class.•We observe the transformation of oil through deregulation.
In oilfield development, vertical longitudinal multipole conductance sensors (VLMCS) have been widely used to measure the water holdup in the oil-water two-phase flow. When water is a continuous ...phase and oil is a discrete phase, the oil phase distribution has a great influence on the VLMCS output. In this paper, a 3D theoretical model of the VLMCS is established, and the output response characteristics are studied, considering an oil bubble behavior in the 3D model. The task is performed by establishing a spherical coordinate system and a cylindrical coordinate system with varying mesh sizes and axial and radial positions. At the same time, finite element analysis is used to study the VLMCS output response characteristics of multiple oil bubbles. The results reveal the effect of oil bubble size and position on the VLMCS output response characteristics, which is of great significance for the measurement of the oil-water two-phase flow parameters and optimization of the VLMCS design. The established model provides a theoretical basis for the engineering applications of the VLMCS.
► Crude-oil phase diagrams studied using SAFT-VR. ► Simple models with few components and minimal fitting. ► Asphaltene precipitation boundary and bubble-dew curve captured using same oil model. ► ...Corroborates liquid–liquid phase separation as precursor to asphaltene precipitation. ► Platform to build understanding of contrasting phase behaviour of different oils.
We present a simplified but consistent picture of asphaltene precipitation from crude oil from a thermodynamic perspective, illustrating its relationship to the familiar bubble curve via the calculation of constant-composition
p–
T phase diagrams that incorporate both the bubble curve and the asphaltene precipitation boundary. Using the statistical associating fluid theory (SAFT) we show that the position of the precipitation boundary can be explained using a very simple fluid model including relatively few components. Our results support the view that the precursor to asphaltene precipitation is a liquid–liquid phase separation due to a demixing instability in the fluid. Moreover, the bubble curve for these systems is seen to represent a boundary between regions of two-phase (liquid–liquid) and three-phase (vapour–liquid–liquid) equilibria.
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