基于IAHP的南海深水井喷快速应急技术优选

为支持深水井喷事故救援决策,有必要开展井喷快速应急技术优选。基于区间层次分析法(IAHP)构建了具有4个一级准则和12个二级准则的深水井喷快速应急技术优选模型。首先得到准则层优先级顺序,即在选用井喷应急技术时,一级准则依次考虑控油能力、作业实施速度、设计制造速度、恶劣环境适应能力等因素;二级准则依次考虑装置控油机理、设计速度、安装作业速度、水合物抑制能力等因子。最后面向南海深水井喷风险,根据优选模型与应急技术特征参数,得到方案层的8种应急技术优选顺序,给出的南海深水井喷控制方案可用于应急预案编制及事故现场应急处置。     

深水关井作业可靠性贝叶斯-GO法分析

为防止深水井喷失控事故,综合考虑人因和设备风险因素,采用贝叶斯-GO法分析深水关井作业可靠性。根据深水关井作业可靠性操作路径建立GO图;按照映射规则,将GO图转换成对应的贝叶斯网络;根据贝叶斯法的前向和后向推理计算规则,得出深水关井作业在不同工况下的成功概率及薄弱风险点。结果表明,多因素影响下的深水关井作业成功概率有所降低,溢流险情的发现时间及防喷器(BOP)控制系统的可靠性对关井作业影响较大。     

深水钻井井喷事故风险控制决策方法

为有效降低深水钻井井喷事故风险,提出一种井喷事故风险控制决策定量评估方法。首先运用贝叶斯网络(BN)建立深水钻井井喷事故评估模型,根据BN网络前向和后向推理原则,确定井喷事故的主要风险因素和发生概率;然后针对导致井喷事故发生的风险因素提出5项风险控制措施,考虑执行风险决策的效用和成本,通过增加效用节点和成本节点,建立深水钻井井喷事故风险控制决策模型,定量评估31项风险决策措施的有效性和总成本。研究结果表明:执行加强人员技能培训和增加功能测试与维护决策的总成本较低,同时可将深水钻井井喷事故风险控制在可接受风险区域。     

基于贝叶斯—LOPA方法的深水钻井安全屏障可靠性分析

据统计,钻井过程是海上井喷事故的高发阶段,为保障钻井安全进行,安装了节流管线、防喷器等安全屏障减缓系统风险,安全屏障的可靠性直接影响钻井安全。利用贝叶斯—LOPA方法建立深水钻井安全屏障可靠性分析模型,以储层-溢流-井涌-井喷为事件链,运用三级井控理论建立独立保护层,每一保护层运用贝叶斯网络方法计算失效概率。在GeNIe软件中完成模型建立,并且完成后验概率计算、敏感性分析、影响力分析。通过分析计算结果给出风险控制关键事件和风险减缓措施,为钻井现场安全工作提出指导意见,确保深水钻井安全有序进行。     

基于DEMATEL/ISM的深水井喷风险影响因素研究*

为提高深水井喷事故风险管理水平，提出研究深水井喷风险影响因素的分析方法。从技术、人员、环境和管理4个方面，识别深水井喷事故风险致因因素，建立深水井喷事故风险评价指标体系；运用矩阵决策实验室分析法（DEMATEL），研究风险因素之间的相互影响关系，计算不同风险因素的中心度和原因度，确定关键风险因素；进一步基于解释结构模型（ISM）划分不同影响因素的层次结构，分析风险因素之间的综合影响关系，建立深水井喷事故风险影响因素模型。结果表明:层级1为近邻致因，可直接导致井喷事故的发生；层级2~7为过渡致因，在风险传递过程中起到桥梁作用，对井喷事故的直接影响较小；而层级8则为本质致因，重视本质致因的改善有利于从根源上降低井喷事故的风险。研究结果可为深水井喷事故风险的预防和控制提供理论依据。     

井场作业人员应急疏散仿真研究

为了研究石油天然气开采作业过程中发生井喷或一氧化碳和硫化氢泄漏等突发事件时井场作业人员的应急疏散规律,以压裂作业为例,采用社会力模型,建立压裂井场模型,将压裂作业中压裂队、试油队和射孔队等作业人员按照常规工作区域分为5组,模拟了井喷失控时压裂井场作业人员撤离至应急集中区域的应急疏散过程。研究结果表明:仿真计算可以间接反映作业人员的真实疏散水平,可评估应急疏散效果;砂罐车附近的作业人员疏散用时最短,液灌附近的作业人员疏散用时最长,在通过狭窄区域时出现了拥堵现象。仿真计算结果可为井场设施摆放、临时房屋建设、应急集中区域选择等井场布置工作提供参考,可用于指导合理应急疏散方案的制订。     

基于智能运维的高速公路交通事故应急救援作业质量评价研究

准确迅速地评价应急救援作业质量对于高质量开展高速公路交通事故应急救援作业至关重要。基于运维作业动态记录，从事故量、事故影响、作业效果和道路属性4个方面构建应急作业质量快速评价体系，采用CRITIC(Criteria Importance Though Intercrieria Correlation)法客观赋权结合VIKOR(VIseKriterijumska Optimizacija I Kompromisno Resenje)法构建评价算法，以Moran’s I分析的指标空间分布特征结合作业部门兴趣点(Point of Interest, POI)数据与路网信息分析应急救援作业的服务可达性与效果的可视化情况。结果表明：指标具有空间相关性，其中事故占道时长及事故处置时长呈显著的空间集聚现象；多数地区可实现1 h全覆盖，其中以珠三角地区最优。研究方法可为提升应急救援作业质量和作业队伍选址提供依据。     

基于CFD的深水钻井溢油事故定量风险评估

针对深水钻井作业过程中的井喷溢油问题,基于计算流体力学(CFD)方法,通过UDF函数给定海流流剖面、波浪入口边界条件和海水静压分布情况,结合标准k-ε方程,采用VOF模型实现对油、气、水三相自由面的追踪,建立了溢油扩散事故数值仿真模型,评估深水条件下溢油扩散危害区域,研究海流流速、溢油量对原油扩散的影响。结果表明,海流流速和溢油量是原油扩散行为和危害区域分布范围的重要影响因素。     

基于事故场景分析的海洋平台火灾概率预测分析

根据美国安全与环境执行局(BSEE)近40a的火灾事故统计资料,选取压缩机单元火灾、热处理单元火灾和井喷火灾作为典型火灾事故场景,利用贝叶斯网络模拟不同场景火灾事故概率及其关键因子影响程度。模拟结果表明,压缩机单元火灾频率为2.1×10-4次/a,热处理单元泄漏火灾频率为2.2×10-4次/a,井喷火灾频率约1.0×10-5次/a;其中41.1%的压缩机单元火灾、24.9%的热处理单元火灾和34.8%的井喷火灾事故与"没有遵守作业指导"有关;其次,"管道布局不合理"、"缺乏日常检查"和"缺乏沟通"分别是压缩机单元火灾、热处理单元火灾和井喷火灾中仅次于"没有遵守作业指导"的关键因素。     

船舶溢油应急反应人的可靠性分析研究

为减小船舶溢油事故应急反应人员失误概率,提升应急处置效果,在对应急人员可靠性主要影响因素识别的基础上,利用模糊贝叶斯网络(BN)建立船舶溢油应急人的可靠性分析(HRA)模型,将应急反应流程抽象为可进行概率推算的BN,实现单个应急任务和全过程人的可靠性的量化评估,并依据该模型对一起船舶溢油事故进行实例研究。结果表明,首先模糊集值专家评估较好地解决应急人员可靠性情境依赖性强,难以量化评估的问题;其次,BN卓越的概率推理性能实现由单个应急任务向全过程人的可靠性的推算;最后得到应急反应人的可靠性主要取决于关键应急任务的完成情况和相关情境因素的影响。     

A capping technique for emergency response in offshore blowout accidents

Capping stack is an emergency shut-in technique that can effectively control offshore blowout accidents. This technique stemmed the spilled oil well (Macondo) in 2010 Deepwater Horizon blowout accident. However, few efforts have been devoted to studying the way to efficiently and safely conduct the operation of capping stack. In this paper, program evaluation and review technique (PERT) was employed to quantitatively design the operation procedure of capping stack. A mechanical model was established to determine the configuration scheme of capping stack. And a sensitivity analysis of operational factors of capping stack was conducted through orthogonal tests. Experimental results recommend to optimize the operation process by reducing the working time of diamond cutting tool down-pass, Lower Marine Riser Package (LMRP) upper riser incision, LMRP and original Blowout Preventer (BOP) separation, and LMRP recovery, in order to guarantee that the whole operation can be completed as scheduled. The results show that the number of ram BOPs has little effect on the equivalent stress of conductors. To improve system reliability, a five-ram capping stack is recommended to be applied in the defined accident scenario. The maximum equivalent stress of conductors rates the drilling vessel offset as the primary factor, followed by shut-in pressure, ocean current and top tension. The drilling vessel offset needs to be given the priority control and the shut-in pressure should be jointly monitored.     

基于马尔可夫方法的水下防喷器可靠性研究

水下防喷器是保障海上钻井安全的关键设备,对其可靠性进行定量评价对井控作业有重要的指导意义.为了弥补现有水下防喷器可靠性评价方法的不足,将水下防喷器的工作状态分为四种,包括无故障可用、关井、井控关键失效及关井时失效.利用Markov方法建立了水下防喷器的Markov模型.通过水下防喷器系统的状态转换图找出了各工作状态的转换关系.通过分析墨西哥湾83口深水井水下防喷器的失效数据,定义了影响水下防喷器可靠性的井控关键失效,并对深水钻井水下防喷器防喷功能的可靠性进行了定量计算.将计算结果与不考虑关井期间的井控关键失效相比较发现,防喷器的防喷失效概率增加了65％.因此传统的定量评价方法可能会得出相对乐观的结论,应在实际生产中给予重视.     

深水钻井隔水管紧急解脱失效动态风险分析

为了分析钻井隔水管紧急解脱失效动态风险,保证深水钻井隔水管紧急解脱安全运行,通过辨识隔水管紧急解脱相关风险因素,以及隔水管紧急解脱失效的潜在后果,采用模糊事故树和事件序列图相结合的方法,建立隔水管紧急解脱失效后果模型;基于映射准则,将模型转换成贝叶斯网络,进行深水钻井隔水管紧急解脱风险的定量分析;研究了紧急解脱动态失效概率和关键致因,并从钻井隔水管系统设计、钻井作业、紧急解脱测试和操作等方面提出预防措施,以降低紧急解脱失效概率;以南海8号钻井平台为研究对象进行案例分析。研究结果表明:1年内隔水管紧急解脱失效的概率区间为0.075 7至0.105 0;台风、不合理的解脱时刻、过提力不足、井口倾角大和内波是导致紧急解脱失效的主要原因;该模型评估结果与实际情况相符合,该方法可用于钻井隔水管紧急解脱失效风险评价。     

Risk analysis of deepwater drilling operations using Bayesian network

Deepwater drilling is one of the high-risk operations in the oil and gas sector due to large uncertainties and extreme operating conditions. In the last few decades Managed Pressure Drilling Operations (MPD) and Underbalanced Drilling (UBD) have become increasingly used as alternatives to conventional drilling operations such as Overbalanced Drilling (OVD) technology. These newer techniques provide several advantages however the blowout risk during these operations is still not fully understood. Blowout is regarded as one of the most catastrophic events in offshore drilling operations; therefore implementation and maintenance of safety measures is essential to maintain risk below the acceptance criteria. This study is aimed at applying the Bayesian Network (BN) to conduct a dynamic safety analysis of deepwater MPD and UBD operations. It investigates different risk factors associated with MPD and UBD technologies, which could lead to a blowout accident. Blowout accident scenarios are investigated and the BNs are developed for MPD and UBD technologies in order to predict the probability of blowout occurrence. The main objective of this paper is to understand MPD and UBD technologies, to identify hazardous events during MPD and UBD operations, to perform failure analysis (modelling) of blowout events and to evaluate plus compare risk. Importance factor analysis in drilling operations is performed to assess contribution of each root cause to the potential accident; the results show that UBD has a higher occurrence probability of kick and blowout compared to MPD technology. The Rotating Control Devices (RCD) failure in MPD technology and increase in flow-through annulus in UBD technology are the most critical situations for kick and blowout.     

CFD simulation study on gas dispersion for risk assessment: A case study of sour gas well blowout

Compared with general blowout, the process of sour gas well blowout is more complex. The exchange of gas state is affected by many factors, and the consequences of the accident are serious. It is difficult to find out the rule of gas dispersion and predict the distribution of toxic gas. Fluent code was used to model the sour gas dispersion in the atmosphere after well blowout. The “12.23” sour gas well blowout, which was happened in Kai County, Chongqing, Sichuan, China, was the research background. The blowout accident model was set up to simulate the real process. Models were built based on real topography. Wind speed and atmospheric stability of the day which the accident happened were set as the operation conditions, and the composition, injection rate, and temperature of the gas at the actual time were set as the boundary conditions of numerical simulation. The analysis of gas dispersion based on simulation results conducted from two aspects, height and dispersion time. A comparison of field data with simulation data demonstrated that CFD technology can be an effective aid to describe the process of sour gas dispersion and can also predict the tendency of gas dispersion and gas distribution. Furthermore, it can provide guidance on design emergency response zone (ERZ).     

Developing safety indicators for preventing offshore oil and gas deepwater drilling blowouts

An important question with respect to the Macondo blowout is whether the accident is a symptom of systemic safety problems in the deepwater drilling industry. An answer to such a question is hard to obtain unless the risk level of the oil and gas (O&G) industry is monitored and evaluated over time. This article presents information and indicators from the Risk Level Project (RNNP) in the Norwegian O&G industry related to safety climate, barriers and undesired incidents, and discusses the relevance for deepwater drilling. The main focus of the major hazard indicators in RNNP is on production installations, whereas only a limited number of incident indicators and barrier indicators are related to mobile drilling units. The number of kicks is an important indicator for the whole drilling industry, because it is an incident with the potential to cause a blowout. Currently, the development and monitoring of safety indicators in the O&G industry seems to be limited to a short list of “accepted” indicators, but there is a need for more extensive monitoring and understanding. This article suggests areas of extensions of the indicators in RNNP for drilling based on experience from the Macondo blowout. The areas are related to schedule and cost, well planning, operational aspects, well incidents, operators’ well response, operational aspects and status of safety critical equipment. Indicators are suggested for some of the areas. For other areas, more research is needed to identify the indicators and their relevance and validity.     

水平井油基钻井液气侵溶解气膨胀运移规律研究

天然气进入井筒并溶解于油基钻井液会对钻井安全产生潜在威胁,溶解气随钻井液运移到井口附近突然发生析出 并膨胀,使气侵早期监测及预警的难度显著增加。为了降低井喷发生概率和钻井作业风险,针对水平井油基钻井液溶解 气运移规律进行了研究。采用气液两相流模型,模拟了不同初始气侵速率情况下甲烷溶解气和游离气随钻井液在水平段 和垂直段的运移过程,得到环空中钻井液的流速变化、甲烷析出过程、井筒环空气液两相流流型变化、泥浆池增量随时 间变化和截面含气率沿程分布等规律。模拟结果表明,油基钻井液发生气侵时的初始进气率存在临界值;在小气侵速率 情况下,侵入环空的甲烷将以溶解气的形式运移到井口,在井口分离释放,对钻井安全构成的威胁较小;而当气侵量超 过临界值时,在环空上部发生气体分离,分离点迅速下移,如不及时控制,在极短时间内便可演化为井喷,危险性极大 。     

基于模糊数学钻井井喷概率计算模型研究

针对目前钻井井喷风险主要是单因素定量分析或者多因素的事故树定性分析,不够全面,定量性差等问题,基于层次分析法和模糊综合评价法,建立了钻井井喷的多因素定性定量分析方法.通过层次分析法对影响钻井井喷的地质、井型井别、钻井参数和人员资质等因素进行分析,根据各因素在钻井井喷中作用大小,采用“1-9”标度法确定各因素的权重.基于模糊数学理论,采用不同的隶属度函数确定方法,建立了适合不同因素的隶属度函数,在此基础上形成了钻井井喷概率计算方法.通过实例计算表明,此模型可以预测钻井井喷的概率,符合现场实际情况,对钻井过程中预防井喷具有一定的指导借鉴作用.     

含硫气田井喷事故行动计划(IAP)编制研究

本文对国内外事故行动计划的研究进展进行了系统性总结,分析了含硫气田井喷事故发生的原因以及特点.结合我国现行的事故应急工作体系,将事故行动计划应用在含硫气田井喷事故应急工作中,提出了针对含硫气田井喷事故的事故行动计划编制方法,建立了包括现状分析、设立事故目标、确定应急组织体系和职责、制定应急处置措施、调配应急资源、开展评估与监控在内的含硫气田井喷事故行动计划编制技术体系.事故行动计划的制定与实施,可有效提高含硫气田应急工作的针对性和指导性,对含硫气田井喷事故应急工作具有重要作用.