A conceptual offshore oil and gas process accident model

The purpose of this paper is to present and discuss an accident prevention model for offshore oil and gas processing environments. The accidents that are considered in this work relate specifically to hydrocarbon release scenarios and any escalating events that follow. Using reported industry data, the elements to prevent an accident scenario are identified and placed within a conceptual model to depict the accident progression. The proposed accident model elements are represented as safety barriers designed to prevent the accident scenario from developing. The accident model is intended to be a tool for highlighting vulnerabilities of oil and gas processing operations and to provide guidance on how to minimize their hazards. These vulnerabilities are discussed by applying the 1988 Piper Alpha and the 2005 BP Texas City disaster scenarios to the model.     

Fire and explosion assessment on oil and gas floating production storage offloading (FPSO): An effective screening and comparison tool

Fires and explosions have been identified as major potential hazards for Oil and Gas Floating Production Storage Offloading (FPSO) installations and pose risk to personnel, assets, and the environment. Current fire and explosion assessment (FEA) tools require physical effect modeling software and follows standards from API, ISO, and engineering practices. However, the tools are not specific to any particular system such as an FPSO, and do not provide comprehensive guidance for safety engineers to perform FEA.This paper discusses the development of a screening and comparison tool for FEA on FPSOs and the incorporation of an expert system into the tool. The results are computerized using MS Excel/VBA to provide a structured and comprehensive assessment on each equipment and module handling natural gas, crude oil, methanol and diesel on FPSO topsides.This tool features built-in calculations for jet and pool fire size estimation for gas/liquid releases, and the ability to perform Quantitative Risk Analysis (QRA) to specify the personnel and equipment risk for varying leak sizes and process conditions. Control and recovery measures are incorporated as an expert system based on report findings, engineering practices, and relevant standards. Bowtie analysis is applied in the tool to define detailed control and recovery measures for the FPSO based on the incident scenarios. An explosion assessment is performed by incorporating physical effect modeling software results.Unique features provided in the tool include fire and radiation contour mapping on an FPSO layout to help determine personnel and equipment risk more accurately and fire pump sizing that can be used to verify the amount of water deluge system required to mitigate fires and explosions. In addition, flexibility of data input (process data, failure rate data, etc.) and user interfaces assist safety engineers to screen and compare process alternatives, check design quality, and evaluate design options at any design stage.     

燃煤热电厂火灾危险性事故树分析

根据燃煤热电厂工艺设置的要求和所使用原料的性质,分析了燃煤热电厂的火灾危险性,用事故树方法分别对输煤皮带火灾、锅炉燃烧室爆燃、汽轮机油泄漏火灾、电缆火灾等4个生产单元的火灾危险性进行了定性分析和定量计算,并根据分析结果针对性地提出了防火措施.     

Risk perception by offshore workers on UK oil and gas platforms

This paper reports the first investigation of risk perception by workers on offshore oil and gas installations on the UK Continental Shelf, following changes in offshore safety legislation in the wake of the Piper Alpha disaster in 1988. The Offshore Safety Case regulations (Health and Safety Executive, 1992, A Guide to the Offshore Installations (Safety Case) Regulations) put the onus on the operator to identify the major hazards and to reduce the risks to As Low As is Reasonably Practicable (ALARP). The regulations specifically state that Quantitative Risk Assessments (QRA) must be used when preparing the Safety Case. However, people do not use QRA when making everyday judgements about risk; they make subjective judgements known as risk perceptions, which are influenced by a number of different factors. This study was designed to complement the extensive QRA calculations that have already been carried out in the development of Safety Cases. The aim was to measure subjective risk perception in offshore personnel and examine how this relates to the more objective risk data available, namely accident records and QRA calculations. This paper describes the Offshore Risk Perception Questionnaire developed to collect the data and reports on UK offshore workers' perceptions of the risks associated with major and minor hazards, work tasks and other activities aboard production platforms.     

Jet Fires Involving Releases of Crude Oil,Gas and Water

A Joint Industry Project was undertaken to study releases representative of those that could occur on offshore installations involving well-stream fluids either at the wellhead or during processing. The project involved a programme of large-scale jet fire experiments to investigate releases involving mixtures of crude oil and gas (simulating ‘live’ crude) and water. Seven oil and gas companies and the UK Health and Safety Executive sponsored the work that was undertaken by Advantica and Shell Global Solutions at the Spadeadam Test Site, Cumbria, UK. The results demonstrate that the presence of water modifies, significantly, the size, shape, thermal characteristics and stability of a jet fire. For an equivalent release of fuel, the distance from the release point within which flame impingement could occur is slightly increased. However, the overall size of the flame, the temperatures within the flame and the overall heat loading to objects within the flame are reduced. The results also indicate that the flame is extinguished if the water content of the well-stream fluid reaches about 55% by mass. Some well-stream fluids contain a lot of water, in some cases up to 80% by mass, and these will not produce jet fires.     

两相射流促进细水雾灭火技术发展

压缩气体射流与水射流混合后所产生的气-水两相射流,可获得连续、高速喷射的细水雾,水滴粒径小,穿入火焰的能力强,可沿水平方向射入火焰中,比喷淋方式水雾灭火可节省90%的用水量,缩短了灭火时间,发挥了细水雾的灭火优势,是细水雾灭火技术的最新发展。所制成的便携式、车载式、固定式的两相射流细水雾灭火装置,可扑灭多种类型的火灾,尤其适合用于扑灭有人存在的空间的火灾。以涡喷发动机为喷射动力的气-水两相射流喷射系统,制成了超大功率的喷射雾状水的消防装备,大幅度提高了控制油、气大火火势的能力和灭火效率。气-水两相射流还有稀释、吹散泄漏出的可燃性气体,防止其点燃的功能,适合于在天然气和有毒有害气体泄漏事故抢险救援中使用。将压缩气体和泡沫液按比例混和后喷射的压缩空气泡沫喷射系统,产生了喷射“干泡沫”的消防车,使灭火用水的利用率提高了8倍,被称为是世界最先进的泡沫灭火技术。气-水两相射流促进了灭火技术革命性的发展,新型的气-水两相射流消防装备不断涌现,展示出了广阔的应用前景。     

Revised fire consequence models for offshore quantitative risk assessment

Offshore oil and gas platforms are well known for their compact geometry, high degree of congestion, limited ventilation and difficult escape routes. A small mishap under such conditions can quickly escalate into a catastrophe. Among all the accidental process-related events occurring offshore, fire is the most frequently reported. It is, therefore, necessary to study the behavior of fires and quantity the hazards posed by them in order to complete a detailed quantitative risk assessment. While there are many consequence models available to predict fire hazards-varying from point source models to highly complex computational fluid dynamic models—only a few have been validated for the unique conditions found offshore.

In this paper, we have considered fire consequence modeling as a suite of sub-models such as individual fire models, radiation model, overpressure model, smoke and toxicity models and human impact models. This comprehensive suite of models was then revised by making the following modifications: (i) fire models: existing fire models have been reviewed and the ones most suitable for offshore conditions were selected; (ii) overpressure impact model: a model has been developed to quantify the overpressure effects from fires to investigate the possible damage from the hot combustion gases released in highly confined compartments; (iii) radiation model: instead of a point/area model, a multipoint grid-based model has been adopted for better modeling and analysis of radiation heat flux consequences. A comparison of the performance of the revised models with the ones used in a commercial software package for offshore risk assessment was also carried out and is discussed in the paper.     

A safety barrier-based accident model for offshore drilling blowouts

Blowout is one of the most serious accidents in the offshore oil and gas industry. Accident records show that most of the offshore blowouts have occurred in the drilling phase. Efficient measures to prevent, mitigate, and control offshore drilling blowouts are important for the entire offshore oil and gas industry. This article proposes a new barrier-based accident model for drilling blowouts. The model is based on the three-level well control theory, and primary and secondary well control barriers and an extra well monitoring barrier are established between the reservoir and the blowout event. The three barriers are illustrated in a graphical model that is similar to the well-known Swiss cheese model. Five additional barriers are established to mitigate and control the blowout accident, and event tree analysis is used to analyze the possible consequence chains. Based on statistical data and literature reviews, failures of each barrier are presented. These failures can be used as guidance for offshore drilling operators to become aware of the vulnerabilities of the safety barrier system, and to assess the risk related to these barriers. The Macondo accident is used as a case study to show how the new model can be used to understand the development of the events leading to the accident. The model can also be used as an aid to prevent future blowouts or to stop the escalation of events.     

Large scale experiments to study fires following the rupture of high pressure pipelines conveying natural gas and natural gas/hydrogen mixtures

As part of the EC funded Naturalhy project, two large scale experiments were conducted to study the hazard presented by the rupture of high pressure transmission pipelines conveying natural gas or a natural gas/hydrogen mixture containing approximately 22% hydrogen by volume. The experiments involved complete rupture of a 150 mm diameter pipeline pressurised to nominally 70 bar. The released gas was ignited and formed a fireball which rose upwards and then burned out. It was followed by a jet fire which continued to increase in length, reaching a maximum of about 100 m before steadily declining as the pipeline depressurised. During the experiments, the flame length and the incident radiation field produced around the fire were measured. Measurements of the overpressure due to pipeline rupture and gas ignition were also recorded. The results showed that the addition of the hydrogen to the natural gas made little difference to radiative characteristics of the fires. However, the fraction of heat radiated by these pipeline fires was significantly higher than that observed for above ground high pressure jet fires (also conducted as part of the Naturalhy project) which achieved flame lengths up to 50 m. Due to the lower density, the natural gas/hydrogen mixture depressurised more quickly and also had a slightly reduced power. Hence, the pipeline conveying the natural gas/hydrogen mixture resulted in a slightly lower hazard in terms of thermal dose compared to the natural gas pipeline, when operating at the same pressure.     

Large scale high pressure jet fires involving natural gas and natural gas/hydrogen mixtures

A series of six large scale high pressure jet fires were conducted using natural gas and natural gas/hydrogen mixtures. Three tests involved natural gas and three involved a mixture of natural gas and hydrogen containing approximately 24% by volume hydrogen. For each fuel, the three tests involved horizontal releases from 20, 35 and 50 mm diameter holes at a gauge pressure of approximately 60 bar. During the experiments, the flame length and the incident radiation field produced around the fire were measured. The fires also engulfed a 1 m diameter horizontal pipe placed across the flow direction and about halfway along the flame. This pipe was instrumented to measure the heat fluxes to the pipe. The data obtained is compared with previous data obtained for various hydrocarbons at large scale.     

烃类流体火灾伤害破坏作用定量分析

对烃类流体火灾的伤害破坏作用进行正确的定量分析是开展重大消防目标火灾风险评估工作的基础。针对烃类流体火灾伤害破坏作用定量分析中存在的问题,系统论述烃类流体火灾伤害破坏作用的定量分析方法,分析并讨论火球、池火、喷射火和蒸气云火灾等不同火灾形式的热辐射通量计算模型及其前提条件,对不同热辐射伤害破坏作用准则及伤害概率模型的适用条件和模型基础进行了论述。     

Determination of human error probabilities for offshore platform musters

The focus of this work is on prediction of human error probabilities during the process of emergency musters on offshore oil and gas production platforms. Due to a lack of human error databases, and in particular human error data for offshore platform musters, an expert judgment technique, the Success Likelihood Index Methodology (SLIM), was adopted as a vehicle to predict human error probabilities. Three muster scenarios of varying severity (man overboard, gas release, and fire and explosion) were studied in detail. A panel of 24 judges active in the offshore oil and gas industry provided data for both the weighting and rating of six performance shaping factors. These data were subsequently processed by means of SLIM to calculate the probability of success for 18 muster actions ranging from point of muster initiator to the final actions in the temporary safe refuge (TSR). The six performance shaping factors considered in this work were stress, complexity, training, experience, event factors and atmospheric factors.     

喷射火对输油管道热影响实验平台设计与验证*

为研究油气并行管道中,天然气管道喷射火对相邻输油管道内流体与管壁的热影响,设计并搭建天然气喷射火对输油管道热影响实验平台。实验平台由环道及冷却系统、火焰系统、控制及数据采集系统3个部分组成。完成平台搭建并验证环道系统气密性后,以0#柴油为介质,开展验证实验。研究结果表明:火焰系统工作可靠且可控,冷却系统能够将柴油温度控制在初馏点以下,数据采集系统能够正常采集油品压力、温度、流量、管壁温度、火焰温度等预定数据,实验平台具备一定可行性与安全性。实验平台可进行在不同管道规格及材质、火灾形式、油品介质及流速条件下的热影响实验。实验平台结合材料性能进行测试,可研究喷射火对管材性能的影响,为油气并行管道的安全运行提供相关实验依据。     

基于Logistic回归模型的呼伦贝尔草原火险预测研究

目前国内外还没有对不同火险条件下草原火险时空发生概率的研究,而这方面研究对草原火灾管理对策和防火救助应急预案的制定具有重要意义.根据呼伦贝尔草原火灾统计月报表和相关气象、社会经济资料,利用Logistic回归模型建立草原火险预测模型,对草原火险进行了空间上的预测.结果表明,日平均风速、日降水量对草原火险影响较大. 以2005年所有火灾案例对草原火险预测模型进行检验,研究表明,该预测方法具有较高的可靠性,可为火灾管理和减灾决策的制定提供指导.     

基于FLACS CFD的不同气油比油气混输管道泄漏火灾后果对比

不同气油比的油气混输管道泄漏后果危害形式和风险差异的准确判断对于管道泄漏应急处置至关重要。以中国西部某油田集输管道为研究对象,针对不同气油比管道泄漏的火灾危害进行了对比分析,构建了FLACS CFD模型,并研究了油气混输管道原油泄漏形成池火的火灾特征和影响范围,以及天然气泄漏形成喷射火的高温分布和影响规律。研究结果表明:应急处置应考虑不同气油比下池火与喷射火危害的差异。在油气混输管线泄漏10 min形成稳定火焰的场景中,气油比低于100 m3/t时,原油池火为火灾危险的主要影响因素;气油比高于200 m3/t时,天然气喷射火为主要影响因素;气油比超过250 m3/t,高温覆盖距离不再明显增加;40 m为此场景下混输油气泄漏喷射火致死距离上限,120 m为温度影响上限。     

A risk-based decision making approach to determine fireproofing requirements against jet fires

API Publication 2218 is one of the most referred practices for fireproofing of onshore structural supports. Despite the extensive citation, it solely considers the effects of pool fire and rarely addresses jet fire outcomes. This absence of an explicit approach is common among all the other major references. Therefore, the basic objective of this paper is to introduce a new approach for determination of the necessity for fireproofing of structural supports against jet fires. For this purpose, the flame geometry and duration of jet fires are simulated for different leak sizes in identified fire potential sources. Then, following a worst-case analysis, those structures that may be impinged by long enough flames are screened out and then characterized by maximum impingement duration for fireproofing purpose. Moreover, each structure is assigned by a failure rate to estimate the degree of vulnerability through a detailed risk assessment. In this regard a new explanatory term called Structure Failure Rate (SFR) is introduced. This approach also enables researchers to quantify the effect of other protective systems (fire and gas detection, emergency shut-down, depressurization and firewalls) on the level of required fireproofing.     

化工园区安全及环境危险性分析

国内化工园区的建设方兴未艾.化工园区的发展在吸引外资,优化资源配置的同时,带来了一系列的安全及环境问题.其危险主要表现为火灾爆炸、污染大气及水体等方面,不但对生态环境造成了危害,而且使附近居民的人身安全及财产受到极大的威胁.分析化工园区的危险性是进一步发展健康、和谐的化工园区的前提.     

Risk indicators for major hazards on offshore installations

Major hazards risk indicators are proposed for offshore installations, based on what has been used by the Petroleum Safety Authority Norway for the Risk Level approach in the Norwegian offshore petroleum industry. Since 2002 also leading indicators are used, in the sense that indicators for barrier performance are included together with the lagging indicators. There are individual indicators for a number of barrier functions, including fire and gas detection, a number of safety valves, active fire protection and mustering of personnel. The performance of the leading indicators during several years of data collection as well as lessons learned from the project are discussed. This is followed by a review of how indicators may be used by individual companies, and how the lessons may be utilised by individual companies to develop risk indicators for individual installations as well as company wide indicators.     

电子封装行业职业有害因素的辨识与分析

从电子封装行业工艺入手,依据国家颁布的职业有害因素分类目录及职业有害因素致病模型,针对电子封装行业插入式(DIP)及表面贴装(QFP/SOIC)制造工艺使用的材料、设备、条件、人员作业特点,对行业内具有共性的职业有害因素进行分析,对工艺过程中存在的职业有害因素作出辨识,并提出把硅粉尘、铅、氩气、高温、环氧树脂、氢氧化钾、噪声、酸雾、重复性静态作业、重复性动态作业等有害因素作为防控重点,为电子封装行业职业有害因素的危害量化评价及其防控措施制定提供了科学依据。