A Decision Analysis of the Oil Blowout at Bravo Platform

The oil blowout problem has received increasing attention as the search for oil has been carried further offshore. Most scientific effort has been on the prevention side via predictions of blowouts and changes in the design of the platforms. Few studies have focused on oil blowouts once they have occurred. This paper is a case study of the oil blowout that occurred on the Bravo platform in the Ekofisk field in the Norwegian sector of the North Sea. The primary data included interviews with the group who directed the Norwegian government response to this blowout. Other data came from preliminary reports made available soon after the incident. The paper describes the physical aspects of the blowout and the existing principles that guided the initial responses from Phillips Petroleum and Norway. These principles are subjected to a critique prior to the description and structuring of the alternatives facing Phillips and Norway as they responded to this crisis. The government actors involved in the blowout response and their roles are also briefly described. Finally, the decisions made by the Norwegian Action Group are classified and described. Following this effort a qualitative evaluation is offered of these decisions

Setting Standards for Chronic Oil Discharges in the North Sea

Public attention has frequently been directed to the large accidental oil spills connected with tanker groundings or breakups and platform blowouts. The operational oil discharges connected with offshore production platforms could, however, have equally severe effects in the offshore environment because the pollution occurs day after day as long as the activities that produce it continue to operate. This study is concerned with such discharges in the North Sea. The study focused on the central actors involved in the standard-setting process for operational or chronic discharges. Each key actor was interviewed in depth to determine their perceptions of the problem, the role of other actors, the alternatives considered and the interactions among actors. This decision-making complex thus includes a variety of decision-making units with varying abilities to influence the outcomes of the standards. Regulator, developer and environmental expert actors formed the basic focus for this effort. The objectives of the regulators and developers are described along with the alternative regulations, treatments and uses of the environment that are considered. Then a comparison and evaluation of the decision process by which Norwegian and U.K. regulators arrived at discharge standards is made. Major findings include the near similarity of the standards set even though the approaches to such standards are perceived to be quite different in each country. Another finding is that entrepreneurial endeavor for oil discharge treatment equipment is a key parameter in deciding on standards since both countries must rely on such effort for what is available. Lack of information on the effects of oil in the sea is another finding along with a minimal role for environmental quality factors in setting standards. Such findings make it difficult to trace trade-offs in the selection process for standard setting. Finally, some suggestions for improvements in this process are noted

Lessons from Major Accidents - A Comparison of the Three Mile Island Nuclear Core Overheat and the North Sea Platform Bravo Blowout

In research carried out at IIASA, David Fischer compares the 1977 offshore oil well blowout at Platform Bravo, Norway, with the 1979 nuclear plant overheat at Three Mile Island, US. The glaring need emerging from the comparison, in the author's view, is for a smaller part of total resources devoted to accident prevention and a larger part to accident management after an accident has occurred. He says the root of the problem is excessive optimism bred by "professional mindset" that nothing can go wrong. The Executive Report details the key managerial events that took place after each accident and shows how similar needs were met at various crisis points during the first days of the developing accidents. From this exposition Fischer then draws general conclusions, including these: Major accidents are not unique, and their similarities offer learning possibilities; accident management should be centralized; all participants in accident management should have predetermined roles; and to assure good, flexible design, accident management must be developed through a dialogue among all key participants

Managing Technological Accidents: Two Blowouts in the North Sea; Proceedings of an IIASA Workshop on Blowout Management, April 1978

A blowout consists of a sudden and uncontrolled release from a well of large amounts of high-pressure gas or gas-oil and carries with it attendant risks of explosion, fire, and pollution; loss of life, equipment and the hydrocarbon fuel itself are all possible. More generally, a blowout may be characterized as a low-probability, high-risk event which may occur when a complex technological process goes out of control. Drilling for oil and gas in the hazardous environment of the North Sea has, over the years, given rise to great efforts to improve safety standards and operating procedures. By the mid-70s many observers felt that blowouts in the area were extremely unlikely if not impossible. Nevertheless, 1977 saw two blowouts in the North Sea, one on the Ekofisk Bravo platform in the Norwegian sector and the other involving an exploratory well being drilled by the Maersk Explorer rig in the Danish sector. The blowouts caused great concern to the general public, to the governments involved, and within the oil industry, and prompted extensive reevaluations of equipment, procedures, and the general philosophy of accident prevention. The management or prevention of such incidents, whose causes lie at the man-technology interface, was the central theme of a Workshop at IIASA which brought together experts on the environment, representatives of the oil industry, and spokesmen for governments and their associated regulatory bodies. This volume is based on the proceedings of the Workshop and is divided into two main parts: the first is an overview of the blowout problem and the second contains the papers presented by the Workshop participants

Second harmonic generation and birefringence of some ternary pnictide semiconductors

A first-principles study of the birefringence and the frequency dependent second harmonic generation (SHG) coefficients of the ternary pnictide semiconductors with formula ABC$_2$ (A = Zn, Cd; B = Si, Ge; C = As, P) with the chalcopyrite structures was carried out. We show that a simple empirical observation that a smaller value of the gap is correlated with larger value of SHG is qualitatively true. However, simple inverse power scaling laws between gaps and SHG were not found. Instead, the real value of the nonlinear response is a result of a very delicate balance between different intraband and interband terms.Comment: 13 pages, 12 figure

Exceptionally Slow Rise in Differential Reflectivity Spectra of Excitons in GaN: Effect of Excitation-induced Dephasing

Femtosecond pump-probe (PP) differential reflectivity spectroscopy (DRS) and four-wave mixing (FWM) experiments were performed simultaneously to study the initial temporal dynamics of the exciton line-shapes in GaN epilayers. Beats between the A-B excitons were found \textit{only for positive time delay} in both PP and FWM experiments. The rise time at negative time delay for the differential reflection spectra was much slower than the FWM signal or PP differential transmission spectroscopy (DTS) at the exciton resonance. A numerical solution of a six band semiconductor Bloch equation model including nonlinearities at the Hartree-Fock level shows that this slow rise in the DRS results from excitation induced dephasing (EID), that is, the strong density dependence of the dephasing time which changes with the laser excitation energy.Comment: 8 figure

Facility for studying the effects of elevated carbon dioxide concentration and increased temperature on crops

The requirements for the experimental study of the effects of global climate change conditions on plants are outlined. A semi-controlled plant growth facility is described which allows the study of elevated CO2 and temperature, and their interaction on the growth of plants under radiation and temperature conditions similar to the field. During an experiment on winter wheat (cv. Mercia), which ran from December 1990 through to August 1991, the facility maintained mean daytime CO2 concentrations of 363 and 692 cm3 m-3 for targets of 350 and 700 cm3 m-3 respectively. Temperatures were set to follow outside ambient or outside ambient +4-degrees-C, and hourly means were within 0.5-degrees-C of the target for 92% of the time for target temperatures greater than 6-degrees-C. Total photosynthetically active radiation incident on the crop (solar radiation supplemented by artifical light with natural photoperiod) was 2% greater than the total measured outside over the same period

Zener transitions between dissipative Bloch bands. II: Current Response at Finite Temperature

We extend, to include the effects of finite temperature, our earlier study of the interband dynamics of electrons with Markoffian dephasing under the influence of uniform static electric fields. We use a simple two-band tight-binding model and study the electric current response as a function of field strength and the model parameters. In addition to the Esaki-Tsu peak, near where the Bloch frequency equals the damping rate, we find current peaks near the Zener resonances, at equally spaced values of the inverse electric field. These become more prominenent and numerous with increasing bandwidth (in units of the temperature, with other parameters fixed). As expected, they broaden with increasing damping (dephasing).Comment: 5 pages, LateX, plus 5 postscript figure

Aftershocks in Modern Perspectives: Complex Earthquake Network, Aging, and Non-Markovianity

The phenomenon of aftershocks is studied in view of science of complexity. In particular, three different concepts are examined: (i) the complex-network representation of seismicity, (ii) the event-event correlations, and (iii) the effects of long-range memory. Regarding (i), it is shown the clustering coefficient of the complex earthquake network exhibits a peculiar behavior at and after main shocks. Regarding (ii), it is found that aftershocks experience aging, and the associated scaling holds. And regarding (iii), the scaling relation to be satisfied by a class of singular Markovian processes is violated, implying the existence of the long-range memory in processes of aftershocks.Comment: 28 pages, 6 figures and 1 table. Acta Geophysica, in pres

Relativistic transition wavelenghts and probabilities for spectral lines of Ne II

Transition wavelengths and probabilities for several 2p4 3p - 2p4 3s and 2p4 3d - 2p4 3p lines in fuorine-like neon ion (NeII) have been calculated within the multiconfiguration Dirac-Fock (MCDF) method with quantum electrodynamics (QED) corrections. The results are compared with all existing experimental and theoretical data