基于安全屏障模型的海上钻完井作业风险分析

海上钻完井作业面临海洋环境恶劣、浅层地质灾害等复杂工况,极易发生油气泄漏、井喷等事故。为有效预防海上钻完井作业事故,提出基于瑞士奶酪模型的安全屏障模型。采用事故树和故障模式及影响分析相结合的方法,分析作业过程风险。该模型根据挪威标准D-010,建立完井作业关井阶段的物理安全屏障和安全屏障控制原理图,在此基础上构建油气泄漏事故树和失效模式与影响分析表,找出关井阶段可能的油气泄漏途径。通过对重要度计算和风险优先度值排序确定作业过程中最薄弱的安全屏障和关键故障模式。结果表明,作业过程中最薄弱的安全屏障是采油树、油管和地面控制井下安全阀(SCSSV),采油树腐蚀、密封失效、油管接头密封失效和SCSSV开关故障是影响作业过程的关键故障模式。     

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.     

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.     

新疆油田钻井井喷风险分级及井控管理

为了减少新疆油田钻井溢流井喷事件,杜绝井喷失控事故,在统计新疆油田影响钻井井喷风险的地质环境因素的基础上,利用模糊数学理论建立了油田基于地质环境因素的钻井井喷风险分级模型,对各个区块的钻井井喷风险程度进行了分级,结果表明南缘山前构造勘探开发区块及克拉美丽气田的钻井井控风险值最高。建议对新疆油田钻井井控进行分级管理,针对不同的钻井井喷风险等级,制定了针对性的井控对策,建议在井控设计时考虑钻井井喷风险分级设计。     

Hydrocarbon releases on oil and gas production platforms: Release scenarios and safety barriers

The main objective of this paper is to present and discuss a set of scenarios that may lead to hydrocarbon releases on offshore oil and gas production platforms. Each release scenario is described by an initiating event (i.e., a deviation), the barrier functions introduced to prevent the initiating event from developing into a release, and how the barrier functions are implemented in terms of barrier systems. Both technical and human/operational safety barriers are considered. The initiating events are divided into five main categories: (1) human and operational errors, (2) technical failures, (3) process upsets, (4) external events or loads, and (5) latent failures from design. The release scenarios may be used as basis for analyses of: (a) the performance of safety barriers introduced to prevent hydrocarbon releases on specific platforms, (b) the platform specific hydrocarbon release frequencies in future quantitative risk analyses, (c) the effect on the total hydrocarbon release frequency of the safety barriers and risk reducing measures (or risk increasing changes).     

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.     

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.     

含硫油气井井控技术及管理方法

伴随着石油工业的发展,井喷、井控不可避免。为防止溢流、井喷,企业、政府投入了大量的人力、物力、财力,成果显著。但同时也产生了一些副作用,过量投资,资源浪费,地层严重污染,含硫油气井更是如此。基于含硫油气井钻完井的特点,制定了含硫油气井井控工作原则,研究了包含防爆、保证防喷器可靠、保证节流放喷相关装置可靠、保证压井相关装置可靠及保证井眼力学完整在内的含硫油气井严格防止井喷失控技术,选用合适的压井方法避免发生井喷技术,简化关井操作程序及修改钻井液密度附加值来全面限制防溢流的技术及其相应的管理方法。对含硫油气井科学、安全、高效的进行井控工作提供了理论指导,对于含硫油气井的开发具有重要的意义。     

基于FLACS的海上钻探平台井喷爆炸事故后果模拟分析*

为研究海上钻探平台井喷燃爆事故后果,运用FLACS软件对某深海钻探平台井喷爆炸事故进行模拟,研究在不同事故场景下气云爆炸发展过程及平台荷载分布规律,讨论井喷速率、风向、点火位置等对爆炸超压的影响。研究结果表明:随泄漏速率增加,爆炸强度和爆炸范围均增大,爆炸严重程度不仅与井喷速率密切相关,同时也受平台结构影响;点火位置会对爆炸超压产生影响,在可燃气体与空气混合气体比例为化学理论当量比处点燃气体,生活区承受的爆炸超压最大;在设施及建构筑物分布较为密集、拥塞度较高的地方产生的爆炸超压更大。研究结果可为可为平台的阻隔防爆性能设计与应急响应提供指导。     

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.     

钻井井喷失控因素分析及预防对策

井喷失控是钻井中的灾难性事故,有必要开展井喷失控研究,找到井喷失控发生的原因和提出防止井喷失控的对策。在统计分析1970年到2009年间中石油发生在钻进过程中的48例井喷失控事故的基础上,通过对防喷器、节流压井管汇、套管、井喷后爆炸起火等井喷失控因素分析,并利用MLS法对上述各种井喷失控因素危险值进行评估。最后,根据井喷失控因素分析和危险值评估结果,结合现有的钻井井控设计,提出了防止钻井井喷失控的对策。     

Application of dynamic risk analysis in offshore drilling processes

Process safety is the common global language used to communicate the strategies of hazard identification, risk assessment and safety management. Process safety is identified as an integral part of process development and focuses on preventing and mitigating major process accidents such as fires, explosions, and toxic releases in process industries. Accident probability estimation is the most vital step to all quantitative risk assessment methods. Drilling process for oil is a hazardous operation and hence safety is one of the major concerns and is often measured in terms of risk. Dynamic risk assessment method is meant to reassess risk in terms of updating initial failure probabilities of events and safety barriers, as new information are made available during a specific operation. In this study, a Bayesian network model is developed to represent a well kick scenario. The concept of dynamic environment is incorporated by feeding the real-time failure probability values (observed at different time intervals) of safety barriers to the Bayesian network in order to obtain the corresponding time-dependent variations in kick consequences. This study reveals the importance of real-time monitoring of safety barrier performances and quantitatively shows the effect of deterioration of barrier performance on kick consequence probabilities. The Macondo blowout incident is used to demonstrate how early warnings in barrier probability variations could have been observed and adequately managed to prevent escalation to severe consequences.     

海上钻井平台安全风险预警模型应用研究

2010年美国墨西哥湾“深水地平线”钻井平台爆炸和2011年我国蓬莱钻井平台井涌事故,引发社会各界对海上钻井平台安全问题的关注.介绍了海洋钻井平台的组成结构,对海洋钻井平台的危险源进行了系统辨识,试图通过对海上钻井平台作业现场危险因素加以观察,诊断、分析警源、警情,警兆,警级,结合专家意见,从人员、设施设备、安全管理、工程地质、海上环境等几个方面建立海上钻井平台安全风险预警体系,采用改进的层次分析法,得出指标权重,构建海洋钻井平台安全风险预警模型,得到量化的预警结果.并通过对某钻井平台的实例分析,提出安全风险的预控对策,以期本模型对海上钻井平台的事故的发生起到一定的防范作用.     

A development in energy flow/barrier analysis

In this paper, the occupational accidents and their effects on people are modeled. The basis of energy flow/barrier analysis is used to define an accident as the impact of a hazardous agent on a target, as a result of failure of control and protective barriers. This definition is enhanced to include serial and parallel barriers and to distinguish energy barriers from target barriers. The barrier attributes are defined and used to create a quantitative scenario-building model. The probability and severity of various accidents are estimated, by studying barrier reliability and efficiency. This approach is used to develop and simulate accident scenarios and to calculate their consequences. This model can be used in complex systems for analyzing the risk and estimating the importance of barriers.     

“Everything was fine”*: An analysis of the drill crew's situation awareness on Deepwater Horizon

PurposeInvestigation reports into the Deepwater Horizon drilling rig disaster identified issues with the drill crew's situation awareness (SA). The aim was to (1) apply the Driller's Situation Awareness (DSA) model to the cognitive data extracted from accident reports from this event to determine if it could help to explain why the crew erroneously concluded that the well was stable, which would (2) provide a preliminary evaluation of the model's validity.MethodThe DSA model was used for a content analysis of the SA components in the accounts of the crew's actions during two Negative Pressure Tests (NPT), in the hours before the blowout.ResultsThe analysis provided (1) insight into the crew's likely cognitive processes before the blowout. In particular, it revealed issues with their interpretation and mental models of the well state, as well as possible influencing factors including expectation, distraction and experience, emphasising the impact that SA can have on process safety. The categorisation has (2) initially suggested that the DSA model does contain the appropriate components.LimitationsThere are limited first hand reports of this event and thus cognitive processes have to be inferred with a degree of caution.Practical implicationsThe findings give a preliminary validation of the DSA model for further use in training and in investigation of well control events. Recommendations based on the findings are offered for assisting driller SA and consequently, for supporting safe and efficient drilling operations. There is also the opportunity to adapt the DSA model and apply the recommendations from the analysis to similar monitoring positions, where SA is essential, within the process industries.     

基于图论的海洋平台连锁风险评价

为控制海洋平台连锁风险,基于图论(GT),提出一种新型定性风险评价方法,将分析对象的复杂风险分析转化为图形分析运算。该方法综合考虑研究对象的风险,重点考虑事故可能的发展模式,建立并转换可能发生的事故的连锁图,用图论算法进行图形运算,得到造成结果事故发生的关键路径、最短路径和点割集,设置并优化安全屏障,防止初始事故发生。最后,结合墨西哥湾事故,建立事故连锁图,通过图形变换与运算得到2条最短路径、3条关键路径和2个点割集,并提出风险控制措施。     

基于系统动力学的井喷事故仿真研究

为动态预测井喷事故发展过程,在分析导致井喷事故主要因素的基础上,结合系统动力学的相关原理,构建井喷事故系统仿真流图,并运用系统动力学仿真软件Vensim对井喷事故的整体流程进行仿真,实现了对油气井安全水平的动态监测和预警。结果表明:井喷事故的发生是由人为因素、管理因素、环境因素、设备因素和法律法规因素四大子系统的交叉耦合作用而导致整个油气井系统的安全水平低于井喷事故的安全临界点所造成的。     

Microwave-assisted preparation of two-dimensional amphiphilic nanoplate herding surfactants for offshore oil spill treatment

Oil spills are the uncontrolled release of liquid hydrocarbon by ruptured pipelines and tanker hulls, or blowouts and leaks from offshore storage facilities and drilling rigs, either by faulty human behaviors or inevitable natural aging processes. Spills cause disastrous environmental and economic consequences, with the effects of marine habitat damage for lasting decades, necessitating a critical need for efficient oil spill mitigation and leakage treatment. In this study, we develop a two-dimensional (2D) amphiphilic nanoplate as the herding surfactant for retracting spilled oil offshore on the seawater surface with various temperature and saline concentrations. Applying 2D nanoplate herding surfactant causes areas of thin oil slick floating on water to largely shrink and form a thick bulk layer. This transformation lays the foundation for the next-step oil treatment and recovery. Microwave-assisted synthesis method was used to fabricate the surface-modified zirconium phosphate (ZrP) nanoplates as the oil herder, which has an amphiphilic characteristic, containing both hydrophilic and hydrophobic properties. The 2D nanoplate surfactants decrease the air-water surface tension to facilitate the oil herding process efficiently. Using this herding procedure, we propose a biocompatible, high herding efficiency and cost-effective 2D herding surfactant fabrication method and offer a new direction for oil treatment in the offshore process safety field.