Offshore Oil Rigs Research Articles

Shift type and season affect adaptation of the 6-sulphatoxymelatonin rhythm in offshore oil rig workers

Previously we have shown that the 6-sulphatoxymelatonin rhythm of oil rig workers on a 2-week night shift (1800–0600 h) adapts to the shift via a phase delay. We now report the findings of a study on two offshore drill crews working a 1 week day (1200–0000 h), 1 week night (0000–1200 h) swing shift. Urine samples were collected every 2–3 h throughout the subjective days, with over-sleep collections, for the measurement of 6-sulphatoxymelatonin by radioimmunoassay. One crew ( n=11), studied in November, showed no change in their 6-sulphatoxymelatonin rhythm during night shift. The other crew ( n=7), studied in March, showed a significant phase advance of the rhythm during night shift. The data indicate that both the type of shift and the season influence the direction and degree of adaptation.

A solution-adaptive mesh procedure for predicting confined explosions

Explosion hazards constitute a significant practical problem for industry. In response to the need for better-resolved predictions for confined explosions, and particularly with a view to advancing safety cases for offshore oil and gas rigs, an existing unstructured, adaptive mesh, finite volume Reynolds-averaged Navier–Stokes computational fluid dynamics code (originally developed to handle non-combusting turbomachinery flows) has been modified to include a one-equation, eddy break-up combustion model. Two benefits accrue from the use of unstructured, solution-adaptive meshes: first, great geometrical flexibility is possible; second, automatic mesh adaptation allows computational effort to be focused on important or interesting areas of the flow by enhancing mesh resolution only where it is required. In the work reported here, the mesh was adaptively refined to achieve flame front capture, and it is shown that this results in a 10%–33% CPU saving for two-dimensional calculations and a saving of between 57% and 70% for three-dimensional calculations. The geometry of the three-dimensional calculations was relatively simple, and it may be expected that the use of unstructured meshes for truly complex geometries will result in CPU savings sufficient to allow an order-of-magnitude increase in either complexity or resolution. © 1998 John Wiley & Sons, Ltd.

A simple general model for echelon overhaul and repair

In echelon overhaul and repair, failed or time-expired machines are removed and replaced by overhauled ones. The removed machines are sent to the rear echelon, typically the maker's works, to be overhauled to ‘good-as-new’. The paper presents a simple model for determining economic overhaul intervals in the presence of minor and major failures, PM and inspection of accessible and inaccessible components, and then goes on to consider how many machines should, for maximum long-term economy, be owned by the operator. The economic implications of an echelon policy for both the owners and the makers are briefly discussed. It is argued that simple models promply applied are often adequate for comparing competing systems and policies. An example involving gas-turbines in off-shore oil-rigs demonstrates the method generally, and in particular shows that the advantages may be dissipated if the overhaulers take too long to process overhauled machines.

Seasickness in totally enclosed motor-propelled survival craft: five offshore oil rig disasters : Landolt, J P, Light, I M, Greenen, M G and Monaco, CAviat Space Environ Med Vol 63 No 2 (1992) pp 138–144 (23 refs)

Five mobile offshore drilling unit disasters--Alexander L. Kielland, Ocean Ranger, Vinland, Ocean Odyssey, and Rowan Gorilla I--were studied to assess the degree to which seasickness occurs and endangers the lives of occupants of totally-enclosed motor-propelled survival craft (TEMPSC). Thousands of other peacetime marine incidents were reviewed and a literature search was conducted to assess the same seasickness problem. The one reported death in the Vinland abandonment appears to be the only one that could be associated, even remotely, with seasickness. It cannot be established whether or not seasickness contributed to the cause of death in the case of the Ocean Ranger victims, but it did occur in 75% or more of TEMPSC occupants in the other four rig disasters. It has occurred both in relatively calm waters of 1-m wave height and in severe seas of 15-m heights. Evacuees in an intact TEMPSC are able to survive many hours of severe seas; consequently, they should not be rescued until the weather and sea conditions improve. Moreover, practical survival training and good leadership is a principal cornerstone in the amelioration of seasickness.

Hypercalcemia complicating an industrial near-drowning

A 28-year-old man presented with lethargy, solmulence, and polyuria following near-drowning in a vessel of an offshore oil rig. Laboratory evaluation demonstrated severe hypercalcemia that responded to saline diuresis and nasogastric suctioning. Calcium salts are used frequently in the drilling and completion of oil wells, and it is presumed that this patient's hypercalcemia represented acute intoxication from swallowed and aspirated fluid. This case highlights the need to consider the potential constituents of the drowning fluid in victims of near-drowning, particularly if unexplained clinical phenomena are evident.

The stress upon rescuers involved in an oil rig disaster. "Alexander L. Kielland" 1980.

Nine months post-disaster, 134 rescuers involved in an off-shore oil rig disaster were investigated by using a structured self report questionnaire to chart their experience of coping with disaster impact stressors and their mental and physical health 9 months after the disaster. Of the 134 rescuers, 24 were categorized as professional rescuers, 101 as non-professionals and 9 could not be classified. Of the 212 victims, all oil rig workers, 89 (42%) were rescued. Seventy-six percent of the rescuers reported they had been exposed to danger during the rescue operation, and 62% found the experience to be the worst ever. Eighty to ninety percent felt they had coped fairly well with the task, and severely disturbed coping was reported to be below 10% for decision-making, ability to judge risk, capacity to function as leader, and finally ability to cooperate and act efficiently. For the non-professionals, severe disturbance in ability to plan before acting was reported by 10% and moderate disturbance was reported by 38%. The frequency of emotional stress reactions during the rescue work can be assessed from the fact that 64% to 52% reported discouragement, restlessness, uncertainty, anxiety and irritation. The stressors inherent in this type of disaster seem to satisfy the DSM III stressor criterion for post-traumatic stress disorder. Nine months after the disaster 24% reported their mental health to be poor due to the disaster impact, and only the most experienced rescuers had a low health risk compared to the others.

Halobacteroides acetoethylicus sp. nov., a New Obligately Anaerobic Halophile Isolated from Deep Subsurface Hypersaline Environments

Summary A halophilic isolate from deep subsurface gas bearing sandstones and brine waters associated with an injection water filter on an offshore oil rig in the Gulf of Mexico was described as a representative of the new species Halobacteroides acetoethylicus sp. nov. The organism is a Gram-negative, non-sporeforming anaerobic rod which exists singly or in pairs. The DNA base composition was 32.0 ± 0.5 mol % G + C. The mesophilic isolate grows in salt concentrations of 5–22% (w/v) and a pH range of 5.3 to 8.0. A doubling time of 7.5 h on glucose was measured at 34°C using a rich medium containing 10% NaCl at a pH of 7.2. The balanced fermentation of glucose yielded ethanol, H 2 /CO 2 and acetic acid. The taxonomic relationship of H. acetoethylicus to other haloanaerobes is discussed.

DIRECTIONAL SPECTRUM ESTIMATION FROM A BAYESIAN APPROACH

A new directional spectral estimation method using a Bayesian approach is proposed. The proposed method is examined for numerical simulation data, and the validity of the method is discussed. Some examples of the directional spectra estimated from field observation data attained at an offshore oil rig utilizing seven wave probes are also shown in this report. The major conclusions of the report are : (1) The proposed method can be applied for more than four arbitrarily mixed instrument array measurements. (2) It has a higher resolution power than other existing methods for estimating directional spectrum. (3) It is a better method for estimating directional spectra from the cross-power spectra contaminated with estimation errors. (4.) It is more adaptable to reformulation of the estimation equations as the study of structures of directional spectrum progesses.

What's for Dinner?

What's for Dinner?

A survey of cannabis use in offshore rig workers.

SummaryA series of offshore oil and gas rig workers were submitted to routine medical examination immediately prior to deployment offshore. Urine analysis for cannabinoids was found to be positive in 9.2%. Subsequent follow‐up showed that no accident had involved this group. New employees had their contracts terminated while established workers were disciplined. It does however pose the problem of another risk factor for accidents in an already hazardous occupation.

Hydrogen and humidity effects on fatigue behavior of a 70–30 copper-nickel alloy

Among the most persistent maintenance problems experienced with offshore oil and gas drilling rigs and production platforms are biofouling and corrosion. Seawater is pumped continuously to provide for ballast systems and engine cooling. Copper-nickel alloys have been used for many years in marine piping applications, and are now being considered for use as cladding for ship hulls and offshore structures. The alloys have good resistance to biofouling and corrosion, but their response to fatigue stresses in aggressive environments has received little attention. The present study was designed to investigate this problem. Reverse torsion fatigue tests on 70-30 copper-nickel alloys containing < 1 pct Fe in 1 atmosphere gaseous hydrogen and humid air environments showed that the fatigue life was reduced by the test environment. Changes in fracture mode were also observed in specimens tested in aggressive environments when compared to those tested in dry helium. The results are discussed in terms of aging, dilation-aided diffusion, and dislocation sweep of the aggressive environment into regions ahead of the crack tip and subsequent failure along microstructural interfaces.

Logistics – Filling the Gap in the Maritime Area

Integrated Logistic Support (ILS) is an important, but apparently neglected, applied science. Its use by engineering project managers should reduce total maintenance costs by minimising expensive unexpected downtime. The science of logistic support is not new, but the value of ILS lies in its methodical formulation and application sound engineering maintenance processes to an engineering system from its inception to the end of its life.The recognition of ILS and its importance by corporate planners should kerb the short-sighted practice of reducing system acquisition costs by largely ignoring long-term maintenance considerations. ILS promises to become more attractive once the RAN gains sufficient experience, evaluating its application to long-term fleet acquisition projects, to quantify overall maintenance savings. In the meantime, any firm operating passenger, cargo and fishing vessels, off-shore (or on- shore) oil rigs, or fish processing plants – to name but a few maritime systems – stands to benefit ...

The psycho-social consequences of intermittent husband absence: An epidemiological study

This paper examines the psycho-social effects on wives of their husbands' intermittent absence on off-shore oil rigs. It is based on data gathered from a random sample of wives living in Aberdeen area, and it proceeds in three stages. The analysis begins with a comparison between wives whose husbands work on- and off-shore, it goes on to examine differential reaction to husband absence in the off-shore group and concludes with an attempt to estimate prevalence of the ‘intermittent husband syndrome’. All the available evidence suggests that the psycho-social effects of intermittent husband absence have been exaggerated. The mental and physical health of wives of men working off-share was similar in most respects to the health of wives whose husbands work on-shore. Within the sample of wives whose husbands worked off-shore those most affected by intermittent husband absence were ‘Novices’ (newly married wives with pre-school children and no previous experience of husband absence), those with outside employment and those experiencing irregular absences. But even among such groups with fairly pronounced mood and behaviour changes there was little evidence of raised levels of morbidity. When defined in terms of specified levels of reactivity, marital conflict and morbidity prevalence of the ‘intermittent husband syndrome’ was found to be around 10%.

Arctic hurricanes

The devastating winter storms that swoop across the Arctic, endangering offshore oil rigs, shipping, and fishing operations in their paths, are the subject of current study by a team of weather researchers from the National Oceanic and Atmospheric Administration (NOAA). As part of the study, U.S. scientists and those from several other countries also will attempt to estimate how much carbon dioxide is transferred from the atmosphere into the North Atlantic's deep waters during winter storms.A typical polar low, like a hurricane, has a spiral cloud pattern and winds exceeding 120 km per hour, said Melvyn Shapiro, senior meteorologist on the polar‐low study. The storms are smaller than most hurricanes, however, and rarely have a diameter greater than 320 km. Some, but not all, develop an “eye,” like a hurricane. Polar lows, only recently documented from polar orbiting satellite imagery, appear to form primarily from October to April, but peak in February.

Air and sea rescue via satellite systems: Even experimental systems have helped survivors of air and sea accidents. Two different approaches are discussed

The Cospas-Sarsat project aims to develop a scheme in which a small battery-powered transmitter on a ship or aircraft would be activated, manually or automatically, in an accident. Once activated, the transmitter, or beacon, would emit a low-power omnidirectional signal that would be picked up by a satellite. The satellite would relay the distress signal to an earth station, which in turn would send the message over conventional communication lines to a rescue center. Concurrently with development work on this project, and experiment with high-orbit geostationary search-and-rescue satellites is in progress. The geostationary experiment is aimed exclusively at the commercial maritime industry and is considering only the technical aspects of the beacon-to-satellite and satellite-to-earth links under uniform, controlled conditions. This program is using satellites and earth stations of Inmarsat, the 31-nation consortium that offers satellite communication services to merchant ships and offshore oil rigs.

“Daddy Come Home Soon!” Intermittent Father Absence and the Family*

Little has been written about the impact on children and families of the intermittent absence, through work, of one or other parent. This article explores some aspects of the interaction between the family and the workplace, using the experiences of the family of an offshore oil rig worker to illustrate some of the problems. Some modes of adaptation are discussed.

Alcohol consumption in offshore oil rig workers.

SummaryThe opportunity was taken in March 1981, to obtain self‐reports from a sample of men working in the North Sea Oil Industry, of the amount of alcohol consumed during the week preceding their period offshore. It was very heavy; approximately 30per cent of 213 men had drunk amounts above the safe limits suggested by the Royal College of Psychiatrists [1]. The findings are compared with data obtained by similar methods in other groups of men by other investigators, and the results discussed.

Noise control for offshore drilling facility

A detail noise survey was conducted on a large offshore oil rig with three drilling machines. The coherence function technique was used to identify noise sources in the equipment rooms, the control room, the radio room, the offices and the crew's living quarters. It was found that the major noise sources were diesel engine generators, mud pumps, air conditioners, ventilation systems, etc. The structure‐borne noises which were generated by engine generators and air conditioners propagated into the control room, the radio room, the offices and the living quarters through steel structures. Because this offshore facility will be operated in the North Sea, the noise levels should comply with the United Kingdom Department of Energy Guidance. Noise control recommendations were provided for the above mentioned areas and the work place on the drilling floor where the noise levels exceeded the criteria specified in the UK DOE's Guidance. The recommendation included the installation of vibration isolaters and silencers for the noise sources. These were successfully implemented. Acoustical treatments of a few special areas were suggested for further noise reduction.

Ixtoc 1 oil spill: flaking of surface mousse in the Gulf of Mexico

The blowout at the Ixtoc 1 offshore oil rig in the Gulf of Mexico (19°24′ N, 92°12′ W) produced a major oil spill. An estimated 140 million gallons of oil escaped before the well was finally capped1; this compares with a spill of 66 million gallons of oil from the tanker Amoco Cadiz2,3. In contrast to the rapid, close-to-shore release of the tanker's cargo, the Ixtoc 1 well released oil for 9 months into the open ocean where winds and currents dispersed the floating mousse (a light brown and orange water-in-oil emulsion) which had formed at the wellhead. Two and a half months after the blowout the western boundary current in the Gulf of Mexico4,5 had brought mousse to the American shore. An ultra-thin sheen also formed from the oil and was visible as a smoothness of sea-surface texture relative to the slightly rougher unpolluted waters. We report here that at a distance of 750–1,000 km from the well, Ixtoc 1 mousse occurred on sheen-covered sea surface primarily as gramme-sized pancakes and milligramme-sized flakes. Relative to pancakes, flakes were more dense, depleted in aliphatic compounds and enriched in polar compounds. Both particles were covered with a brittle 5–10 µm skin. Pancakes, skin, flakes and surface sheen seem to represent the four macroscopic component parts of a pelagic weathering cycle of Ixtoc 1 mousse.

Possible Accumulation of Heavy Metals Around Offshore Oil Production Facilities in the Beaufort Sea

The heavy metals chromium, zinc, cadmium and lead have accumulated in the sediments around some offshore oil rigs. Oil production is now being considered for some nearshore sections of the Beaufort Sea coast. During winter in the Beaufort Sea, heavy metals in the sediments will not be dispersed; the under-ice currents are slow, and some of the bottom is coverd by very saline, relatively stagnant water. Heavy metals in the sediments can probably be assimilated by epibenthic animals in the nearshore region, and then transferred through the food chain to natives who partially subsist on marine animals.