North Sea Oil Production Platforms Research Articles

All at sea: An ergonomic analysis of oil production platform control rooms

Control rooms on offshore production platforms are the focal point for their safe and efficient operation. Following the Piper Alpha disaster in 1988 a sizeable body of safety literature was generated covering the Ergonomic/Human Factors issues then in play. More than twenty years have passed since that time and significant changes have occurred to how control rooms are manned and the technology now in use. As the North Sea oil industry in the UK enters a new phase in its life cycle, and becomes subject to unprecedented production and cost pressures, it is time to revisit these issues. This paper reports on a high-level ergonomic survey covering approximately a third of all North Sea control rooms. The focus is on the adaptive capacity of the highly experienced control room operators and the current challenges to that capacity. Areas of concern include the support provided for dealing with non-routine events, the persistent issue of ‘alarm overload’, the flexibility and control of current SCADA systems, the use of control rooms for non-related tasks, and the possible role of non-technical skills training. Relevance to industryA high-level control room survey covering a third of all North Sea oil production platforms is presented. Control rooms have co-evolved with their highly experienced users and care needs to be taken in how ergonomic issues are tackled. The survey reveals persistent issues around alarms, the support provided to operators in non-routine and emergency situations, and the use of the control room as a focal point for non-control room activities.

Comments: Offshore Resilience

Editor's column Twenty-five years ago next month, the oil and gas industry’s worst offshore disaster took place. The explosion and fire on the Piper Alpha North Sea oil production platform killed 167 men and left only 61 survivors. The anniversary will be commemorated with a 3-day safety conference in Aberdeen and the refurbishment of a memorial sculpture honoring the victims. The accident ushered in a new safety culture in the oil and gas industry as well as a new regulatory mandate. That sector of the industry recovered and has made steady improvements in safety since. Three years ago, the Macondo Gulf of Mexico accident rocked the industry, and its implications are still being felt. From all appearances at last month’s Offshore Technology Conference in Houston, the offshore sector is booming and even more mindful of the necessity of safe operations amid an exploration renaissance. Operators expect a tougher regulatory regime in the Gulf of Mexico going for-ward, one that could lead to some industry consolidation, according to a survey report released at OTC by GL Noble Denton. The survey of 100 senior oil and gas industry executives found that 85% of respondents expect the US regulatory regime to become much tougher over the next 2 years and 61% believe that regime will negatively affect their businesses. Speakers at OTC sessions echoed those sentiments. The industry should expect new rules about well control equipment, blowout preventers, and production systems, according to Randall Luthi, president of the National Ocean Industries Association. But he expects overall production from the Gulf of Mexico to continue to increase, and communication between regulators and the industry to continue to improve. E&P activity has rebounded in the Gulf since Macondo. New rigs are being delivered and wildcat wells are being drilled. The most recent deepwater activity report issued by the US government shows a total of 36 floating rigs operating in the Gulf compared with 30 at the time of the Macondo accident, and a total of 51 projects are under way in more than 1,000 ft of water. In a keynote speech at the recent SPE European HSE Conference and Exhibition in London, Phil Hemmens, managing director of Eni UK, said he believes high-profile accidents such as Macondo and Piper Alpha put a burden on the industry to prove that it can manage its operations safely. The industry has made great strides over the past 30 or so years in raising safety standards and measuring occupational safety performance in a way understandable to regulators and the public. But it does not have key performance indicators (KPIs) that might indicate the potential for a major accident such as Macondo, he said. Although the industry has some indicators—information gleaned from near-misses or types of hydrocarbon releases—the complexity of deepwater and other projects has made standardizing KPIs difficult. Developing those indicators, and then applying them industrywide, would help both the industry and regulators identify and manage risk at the operational level more efficiently.

Low-dose exposure to alkylphenols adversely affects the sexual development of Atlantic cod ( Gadus morhua): Acceleration of the onset of puberty and delayed seasonal gonad development in mature female cod

Produced water (PW), a by-product of the oil-production process, contains large amount of alkylphenols (APs) and other harmful oil compounds. In the last 20 years, there have been increasing concerns regarding the environmental impact of large increases in the amounts of PW released into the North Sea. We have previously shown that low levels of APs can induce disruption of the endocrine and reproductive systems of Atlantic cod ( Gadus morhua). The aims of this follow-up study were to: (i) identify the lowest observable effect concentration of APs; (ii) study the effects of exposure to real PW, obtained from a North Sea oil-production platform; and (iii) study the biological mechanism of endocrine disruption in female cod. Fish were fed with feed paste containing several concentrations of four different APs (4- tert-butylphenol, 4- n-pentylphenol, 4- n-hexylphenol and 4- n-heptylphenol) or real PW for 20 weeks throughout the normal period of vitellogenesis in Atlantic cod from October to January. Male and female cod, exposed to AP and PW, were compared to unexposed fish and to fish fed paste containing 17β-oestradiol (E 2). Approximately 60% of the females and 96% of the males in the unexposed groups were mature at the end of the experiment. Our results show that exposure to APs and E 2 have different effects depending on the developmental stage of the fish. We observed that juvenile females are advanced into puberty and maturation, while gonad development was delayed in both maturing females and males. The AP-exposed groups contained increased numbers of mature females, and significant differences between the untreated group and the AP-treated groups were seen down to a dose of 4 μg AP/kg body weight. In the high-dose AP and the E 2 exposed groups, all females matured and no juveniles were seen. These results suggest that AP-exposure can affect the timing of the onset of puberty in fish even at extremely low concentrations. Importantly, similar effects were not seen in the fish that were exposed to real PW.

Produced water extracts from North Sea oil production platforms result in cellular oxidative stress in a rainbow trout in vitro bioassay

Produced water (PW) discharged from offshore oil industry contains chemicals known to contribute to different mechanisms of toxicity. The present study aimed to investigate oxidative stress and cytotoxicity in rainbow trout primary hepatocytes exposed to the water soluble and particulate organic fraction of PW from 10 different North Sea oil production platforms. The PW fractions caused a concentration-dependent increase in reactive oxygen species (ROS) after 1 h exposure, as well as changes in levels of total glutathione (tGSH) and cytotoxicity after 96 h. Interestingly, the water soluble organic compounds of PW were major contributors to oxidative stress and cytotoxicity, and effects was not correlated to the content of total oil in PW. Bioassay effects were only observed at high PW concentrations (3-fold concentrated), indicating that bioaccumulation needs to occur to cause similar short term toxic effects in wild fish.

Estrogen receptor (ER) agonists and androgen receptor (AR) antagonists in effluents from Norwegian North Sea oil production platforms

The in vitro estrogen receptor (ER) agonist and androgen receptor (AR) antagonist potencies of offshore produced water effluents collected from the Norwegian Sector were determined using recombinant yeast estrogen and androgen screens. Solid phase extraction (SPE) concentrates of the effluents showed E2 agonist activities similar to those previously reported for the United Kingdom (UK) Continental Shelf (<0.1–4 ng E2 L −1). No activity was detected in the filtered oil droplets suggesting that produced water ER activity is primarily associated with the dissolved phase. Targeted analysis for methyl- to nonyl-substituted alkylphenol isomers show the occurrence of known ER agonists in the analysed samples. For the first time, AR antagonists were detected in both the dissolved and oil associated phase at concentrations of between 20 and 8000 μg of flutamide equivalents L −1. The identity of the AR antagonists is unknown, however this represents a significant input into the marine environment of unknown compounds that exert a known biological effect. It is recommended that further analysis using techniques such as bioassay-directed analysis is performed to identify the compounds/groups of compounds that are responsible in order to improve the assessment of the risk posed by produced water discharges to the marine environment.

Digests or extracts??Some interesting but conflicting results for three widely differing polluted sediment samples

Three sets of samples have been investigated in some detail. One set is from a river polluted by mine workings, containing substantial levels of Fe, Mn,Cu, Zn and Ni with traces of many other metals. The second set consists of typical estuarine sediments contaminated from a wide range of industrial sources, and the third set consists of oily drilling cuttings from the sea bottom in the vicinity of a North Sea oil production platform.

Toxicity testing of oil-contaminated drilling cuttings

The luminescent bacterium Photobacterium phosphoreum has been used to examine samples of oily drilling cuttings from the sea bottom in the vicinity of a North Sea oil production platform. Because the presence of any fine particulate matter results in a depression of the bioluminescence, the cuttings must first be extracted and the extract filtered before mixing with the bacterial suspension. A sea-water extract of a low toxicity drilling oil gave a small but significant depression of bioluminescence, but extracts with 1% v/v ethanol or DMSO gave a 50% greater depression. Samples of cuttings from different depths (representing different ages, up to 15 years) showed a different pattern, with similar effects from the aqueous and the mixed-solvent extracts. It is assumed that the toxic component therefore is not originating from the drilling mud oil, but from some additive which has a rather higher solubility in water than the hydrocarbons.

Acute and chronic toxicity of produced water from a North Sea oil production platform to the calanoid copepod Acartia tonsa.

The routine operation of offshore oil production platforms results in the discharge to the sea of produced water after it has been separated from oil drawn from the reservoir. Discharge of produced water in the UK sector of the North Sea is given an exemption from the provisions of the 1971 Prevention of Oil Pollution Act providing the monthly average oil-in-water content measured twice per day does not exceed 40 mg kg{sup {minus}1}. To assess the toxic hazard to marine organisms of produced water discharged to the North Sea, within this exemption, Shell UK Exploration and Production has implemented a research program. Methods for determining the acute and chronic toxicity of produced water to the marine calanoid copepod Acartia tonsa have been established and applied at Shell's Sittingbourne Research Centre to samples from the Shell/Esso Dunlin A platform. This paper describes the methods used to assess acute and chronic toxicity and the results of tests performed on a sample of produced water collected in February 1986. Tests were performed on subsamples of the bulk sample which: (a) were untreated (b) had been filtered and (c) biodegraded (i.e., organic substances present in the produced water were degraded by micro-organisms) and thenmore » filtered. The results of the tests are discussed in relation to the likely patterns of dilution offshore in the North Sea.« less

Birth, growth and death rates for enclosed populations of calanoid copepods

Rates of birth, growth and death are inferred for enclosed populations of the marine copepods Pseudocalanus elongates, Acartia clausi and Temora longicomis. The rates are determined by fitting a population dynamics model to the time series of developmental stage abundances observed over 87 days in four 310 m3 enclosures. Two enclosures were treated with ‘produced’ water from North Sea oil production platforms and two were untreated controls. The pollutant mainly affected recruitment to the populations. Development times varied considerably between enclosures, though not in any apparent relation to the pollutant. Mortality was most strongly related to the population size of herring larvae introduced to all four enclosures. Levels of secondary production derived from the model were compared with those calculated directly from population densities.

Offshore macrobenthic recovery in the Murchison field following the termination of drill-cuttings discharges

The effects of discharged drilling cuttings contaminated with oil-based drilling fluids on the macrobenthos surrounding several North Sea oil-production platforms have been well documented. Areas of biological effect ranging from highly modified benthic communities, through transitional zones to undisturbed zones have been identified and characterized. Results are presented from a series of studies at the Murchison oil field which indicate partial recovery of macrofaunal communities around the production platform after cuttings discharges had ceased. Eventual rates of recovery of affected macrobenthic communities around production platforms are discussed in terms of persistence of oil in the drilling cuttings and the rates of degradation of the oil and its toxic components.

Biogenic and pollutant aliphatic hydrocarbons in Mytilus edulis from the North Sea

Capillary gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS) have been used to examine the aliphatic hydrocarbon fraction of specimens of the mussel, Mytilus edulis, collected from the legs of a North Sea oil-production platform. In addition to an unresolved complex mixture (UCM) of fossil fuel pollutant hydrocarbons ( ca. 64 μg g −1 dry weight average), the fraction was dominated by large amounts ( ca. 21 μgg −1 dry weight) of C 31 and C 33 n-alkenes with 2, 3 and 4 double bonds. These alkenes have also been identified in the ubiquitous marine alga, Emiliania huxleyi, and in some species of fish taken from the North Sea. The close correspondence in the composition data suggest that, in the mussel, these alkenes arise from a biogenic dietary source, most probably from Emiliania huxleyi. This contention is supported by the identification in the mussel of unusual C 37, C 38 and C 39 unsaturated straight-chain ketones which have recently been shown to be biosynthesised by Emiliania.

Investigation of the sources of aliphatic hydrocarbons in the musselMytilus edulisfrom north sea oil production platforms by Capillary glc and CGCMS†

Aliphatic hydrocarbons isolated from mussels collected over a 20 month period from three North Sea Forties field oil production platforms have been examined by capillary gas chromatography and gas chromatography‐mass spectrometry. The biological hydrocarbons consist predominantly (300–700 μh g‐1 lipid) of C31 and C33 n‐alkenes with 2, 3 and 4 double bonds probably derived from a dietary intake of Emiliania huxleyi, a microscopic coccolithophorid alga. In some of the mussels C18, C20 and C22 n‐alkanes are present in unusually high abundance compared to their odd carbon number homologues. Possible reasons for this distribution are discussed. The concentrations of fossil fuel hydrocarbons (mainly unresolved complex mixtures) in the mussels ranged from 330 to 5,298 μg g‐1 of lipid. No significant increase in values was detected two months after the start of discharge of treated Forties production water from the Forties D platform. To determine the pollutant hydrocarbon sources, the sterane and terpane distributions of hydrocarbon fractions isolated from the mussels and from a number of fossil fuels, including Forties crude oil, were examined by mass fragmentography. The steranes in the mussels from the Forties C and D platforms contained higher proportions of regular 14α(H), 17α(H) components than Forties oil in which the steranes were mainly 13ß(H), 17α(H) diasteranes. In addition, the terpane distributions of the mussel fractions differed markedly from that of Forties crude oil, particularly in the relative abundance of diterpanes to triterpanes, which was higher in the mussel fractions than in the oil, and in the absence of 17α(H), 18α(H), 21ß(H)‐18, 30‐bisnorhopane, a known component of Forties crude. Furthermore, the ratio of C29 to C30 triterpanes was greater than unity in the mussels but much less than unity in the Forties oil. These data preclude Forties or other similar North Sea crudes as the major source of pollutant aliphatic hydrocarbons in the mussels. The relative concentrations and distributions of steranes and triterpanes suggest that the most likely source of pollutants is a Middle Eastern based oil derived either from rig activities, or from background pollution in the North Sea. The low concentration of ≥ C27 steranes in the more polluted mussels (e.g. Forties B; UCM > 200 ppm dry wt.) suggests that gas oils used on the platforms may be the major source of petrogenic hydrocarbons in these samples.

The use of steel and concrete in the construction of North Sea oil production platforms

The main areas of uncertainty in the materials field associated with the use of steel and concrete for the construction of North Sea oil production platforms are reviewed. The effects of corrosion from the seawater and corrosion fatigue from wave action are given particular attention. The long-term performance of steel and concrete in this environment is considered against current design and certification requirements and the need to undertake regular inspection and maintenance of platforms during their lifetime.

A Simulator to Train Process Operators of Substitute for Natural Gas Plants

Simulators can be invaluable aids to process operator training, but their benefits can only be realised by means of good functional design resulting from a careful analysis of the training problem. Simulator usage and design are discussed, and the general principles raised are illustrated with respect to a substitute natural gas process simulator designed and constructed for the British Gas Corporation, and a North Sea oil production platform simulator being designed for Pergamon Press Ltd.