Explosion risk on offshore and onshore facilities—is there an explosion risk problem or an explosion modelling problem?

2015 ◽  
Vol 55 (1) ◽  
pp. 337
Author(s):  
Ingar Fossan ◽  
Sverre Nodland

Management of the risk related to the loss of containment of flammable fluid is paramount to ensure safe operations at facilities processing or storing flammable fluids. According to best industry practice, an extensive set of safety functions—including measures that reduce the frequency of initiating events (e.g. leaks) and measures that mitigate consequences in case of ignition—are implemented in design to control the risk. Adopting the risk-based design principles that are commonly enforced in the oil and gas industry, the performance of implemented safety barriers are assessed both qualitatively and quantitatively using different methodologies such as hazard and operability analysis (HAZOP), failure mode and effects analysis (FMEA), and quantitative risk analysis (QRA). The ultimate outcome from the QRA methodology is used to assess the overall risk level as well as to assess dimensioning accidental loads (DALs) for equipment and structures that will ensure a design that is within the tolerable risk level set for the facility. An accurate assessment of DALs resulting from fires and explosion is crucial to manage both the risk and corresponding cost driving factors. The most critical safety barrier in this regard is to minimise leaks and thereafter to prevent ignition of the dispersed flammable fluid. A fundamental safety design principle is to find ways to avoid the occurrence of incidents rather than implement measures that mitigate consequences. This peer-reviewed paper demonstrates the significance of modelling the safety functions that are in place to ensure that the initial leak does not ignite by presenting a case example for different layouts of a conventional jacket installation with gas turbines. It is concluded that the difference between various available ignition models can be more prominent than the uncertainty related to any other model element in the QRA. To uncover potential hazards not reflected by the model and identify optimal control measures, the effect of the ignition model applied should be investigated in detail for installations where the QRA displays a prominent fire and explosion frequency.

Author(s):  
Abdullah N. AlKhudhayr ◽  
Abdulrahman M. AlAdel

Abstract A gas turbine is a reliable type of rotating equipment, utilized in various applications. It is well known in power generation and aviation. In the oil and gas industry, gas turbines are utilized in locations with limited electrical power or a high power driven load requirement, such as offshore or a high-rated power 20MW compressor. Five gas turbines are used as mechanical drive equipment. After a few years of operation, the gas turbines were experiencing high operating temperatures in bearings, turbine compartments, high spread temperature, and the presence of smoke in the exhaust. During a major overhaul of the turbines, oil was found to have accumulated internally in the wrapper casing, along with damage to several internal combustion components. In one case, the exhaust casing experienced severe damage with deformation. This paper presents a case study of a gas turbine failure and its contributors. The paper explains the mitigated solution to overcome the challenges related to the gas turbine operation, maintenance, and machine design.


Author(s):  
Xian-Kui Zhu ◽  
Tom McGaughy

Abstract The low-constraint fracture toughness can be measured using a single edge-notched tension (SENT) specimen in the clamped-end conditions. The SENT specimen has been used in the oil and gas industry in the strain-based design and the crack assessment for transmission pipelines. Since 2006 when DNV published the first SENT test practice, many investigations have been done, and various SENT test methods were developed, including CANMET and ExxonMobil methods in terms of the J-integral and CTOD. The effort led to the first SENT test standard BS 8571 being published in 2014. However, the experimental evaluation methods remain in developing, and different methods may determine inconsistent results. For this reason, the present paper gives a brief review on SENT fracture testing and assesses the available test methods, including progresses on study of stress intensity factor, geometric eta factors, elastic compliance equation, and constraint m factor as well. The difference between J-converted CTOD and double clip gage measured CTOD is also discussed. On those bases, agreements and challenges in SENT testing are identified. The results provide a direction for further investigation to improve the current SENT test methods.


2019 ◽  
Vol 65 ◽  
pp. 08001
Author(s):  
Inesa Khvostina ◽  
Nataliia Havadzyn ◽  
Nataliia Yurchenko

The article presents a study on risks in oil and gas industry and reveals their causes investigating enterprises activity as a result of emergent properties of systems. The original algorithm of risk assessment process based on emergent properties study is offered. A taxonomy approach and factor analysis are used for purposes of risk evaluation. The risk assessment consists of risks taxonomy, database structure development, identification of risks through impact factors evaluation; economic system emergent properties risks prediction, an integral risk level indicator calculation using taxonomy approach, correlation analysis of integral indicators of risk assessment, preventive measures for minimizing of negative impacts and reducing risks.


2011 ◽  
Vol 48 (11) ◽  
pp. 1658-1673 ◽  
Author(s):  
M.S. Hossain ◽  
M.J. Cassidy ◽  
R. Baker ◽  
M.F. Randolph

“Spudcan” foundations for mobile drilling rigs continue to exhibit a high failure rate in the offshore oil and gas industry. The more frequent use of larger jack-ups in highly stratified regions, such as the Sunda Shelf in Southeast Asia, contributes to this concerning increase in “punch-through” incidents, which can lead to buckling of a leg or even toppling of the rig. An industry practice known as “perforation drilling” is sometimes used to mitigate the punch-through risk in layered clays, extracting soil from the upper strong layer before the jack-up is installed. This paper reports results from centrifuge model tests exploring the efficiency of perforation drilling. The soil conditions tested simulate offshore strength profiles that have reported punch-through failures. An experimental method for “drilling” sites in an enhanced gravity centrifuge environment was developed and the installation responses of model spudcan foundations penetrating through multi-layered clays with interbedded stiff layers were recorded. The experimental results show that the removal of soil inside the spudcan perimeter, with an area of 9% perforated, eliminated rapid leg run and severe punch-through on the two- and four-layer seabed profiles tested. This confirms the effectiveness of perforation drilling and indicates how the offshore drilling plan may be optimized.


Author(s):  
Ryan D. Mitchell ◽  
Henry L. Bernstein ◽  
Peggy L. Talley

A study of casing distortion in General Electric MS3002 gas turbines used in the oil and gas industry revealed significant distortion for MS3002 Models C through G. The primary distortion problem was ovalization of the turbine casing, which could occur in either the horizontal or vertical directions. Malfunctioning of the water cooling system, or improper disassembly and assembly procedures can cause casing distortion. The MS3002 Models A-G gas turbines have water cooled turbine casings, and malfunctioning of their cooling water systems, regardless of distortion, is also a significant problem.


2019 ◽  
Vol 59 (2) ◽  
pp. 546
Author(s):  
Peter Cox

Project delivery technology is changing and developing at a rapid rate, and Australia’s oil and gas industry could do a better job of embracing change and getting to the forefront of advanced digital technology applied to developing onshore gas resources – particularly to our vast undeveloped shale reserves. Our shale deposits are in remote parts of our country, so present significant challenges, especially in relation to geographical distance away from local and international markets. This paper will focus on the use of automation and standardisation in the engineering design process combined with project execution strategies to significantly reduce both schedule and cost in delivering surface infrastructure required to get our gas shale reserves to both domestic demand centres and export facilities. The traditional project delivery models that have served us well in the past need to be challenged and a new paradigm adopted. Standardisation of the compression and dehydration facilities in the US market has been developed over many years, resulting in efficient project delivery, and enabling reserves to be brought to market on a fast track basis. This paper will work through practices in the US and how they can be applied to Australia. Australian standards and industry practice defines how we design our gathering and pipeline networks. This paper will present a combination of construction strategies and automation of engineering design to optimise life cycle cost in remote regions where construction mobilisation and logistics is a significant factor combined with changing priorities as further reservoir data is obtained from exploration wells.


Author(s):  
Matt Taher ◽  
Cyrus Meher-Homji

Gas turbine driven centrifugal compressors are widely used in the oil and gas industry. In evaluating the optimum selection of gas turbine drivers for centrifugal compressors, one of the main objectives should be to verify proper integration and matching of the centrifugal compressor to its gas turbine driver. Gas turbines are of standard designs, while centrifugal compressors are specifically designed to meet customer requirements. The purchaser should clearly specify process requirements and define possible operating scenarios for the entire life of the gas turbine driven centrifugal compressor train. Process requirements defined by the purchaser, will be used by the compressor designer to shape the aero-thermodynamic behavior of the compressor and characterize compressor performance. When designing a centrifugal compressor to be driven by a specific gas turbine, other design requirements are automatically introduced to centrifugal compressor design. Off-design performance, optimum power turbine speeds at site conditions as well as optimum power margin required for a future-oriented design must all be considered. Design and off-design performance of the selected gas turbine at site conditions influences the final selection of a properly matched centrifugal compressor design. In order to evaluate different designs and select the most technically viable solution, the purchaser should have a clear understanding of the factors influencing a proper match for a centrifugal compressor and its gas turbine driver. This paper discusses criteria for evaluating the most efficient combination of a centrifugal compressor and its gas turbine driver as an integral package from a purchaser’s viewpoint. It also addresses API standard requirements on gas turbine driven centrifugal compressors.


Author(s):  
Svein Herman Nilsen ◽  
Massimiliano Russo ◽  
Guttorm Grytøyr

Over the last decades, the complexity and duration of offshore drilling operations have steadily increased. The size and weight of the risers and BOP stack has grown significantly. These factors have led to an increase in fatigue loads imposed on the wellhead structures during drilling and completion operations. Wellhead fatigue might ultimately lead to loss of well structural integrity and pressure containment and therefore safe and reliable drilling of subsea wellheads has gained high priority in the global oil and gas industry. This paper presents two of the most complex real time instrumentation campaigns for drilling operations. Analyses of a connected drilling riser system including the well structure are complex and involve several engineering disciplines. In addition, there are many unknowns going into the equations when accumulated fatigue damage of the wellhead is estimated. Therefore, assumptions need to be made, very often on the conservative side. A typical example are the global drilling riser analyses where the environmental conditions, actual rig motion and riser / BOP behavior are uncertain. With the duplex scope of accurately documenting the wellhead fatigue status during drilling operations and of achieving a better understanding of the actual risk level of wellhead fatigue, Statoil decided to start a very comprehensive monitoring campaign. Two MODU representing very different generations of rigs in terms of weights and types of equipment were instrumented from topside to BOP connector. Strain gauges were installed around the BOP connector as close as possible to the wellhead in order to capture wellhead response as accurately as possible. Due to the large number of sensors, high accuracy requirement and high sampling frequency of data to be shown live, a cabled solution was selected vs remote battery operated sensors transmitting via acoustic. Double set of cables, sensors and topside equipment were installed in order to make the instrumentation system fully redundant and suited for permanent installation. All data were additionally made available real time onshore to allow the full overview of the operation. To author’s knowledge, these two instrumentation systems are the most comprehensive and complex of this type installed on a drilling riser as of today. The first of the two system was installed approximately three years ago and it is still in operation. This paper describes the instrumentation systems installed and gives an extract of the quality data extracted and already used in already published studies [1, 2, 3].


2015 ◽  
Vol 55 (1) ◽  
pp. 379
Author(s):  
Andrew Derbyshire

As the concept of risk management has gathered momentum in the oil and gas industry during the past decade, so to has the adoption of IEC 61511, the internationally recognised standard for functional safety in the process industry. IEC 61511 is a risk-based standard that uses the concept of an electrical/electronic/programmable electronic based control system to implement autonomous means of risk reduction against a pre-defined unwanted hazardous deviation in a process. While IEC 61511 has been in existence for more than a decade, the correct understanding and implementation of the standard to derive an effective demonstrate of compliance is still debatable. The standard follows a cradle-to-grave approach to the lifecycle of any safety instrumented system and, unlike other standards where cherry-picking of the requirements may be carried out, IEC 61511 necessitates a demonstration of compliance to all lifecycle phases and their associated requirements. The author of this peer-reviewed paper is fully aware of how difficult-to-digest the subject is; therefore, this paper on the prominence of validation and verification is presented in a pictorial, unambiguous and easy-to-digest manner while paying particular attention to the requirements defined for validation and verification in the standard. The topic of validation and verification in the overall lifecycle of IEC 61511 will be covered by the following questions: What is the difference between validation and verification in the context of IEC 61511? What is the difference between verification against IEC 61511 and IEC 61508? When should planning for validation and verification happen? When should validation and verification be carried out? What are the implications of not carrying out validation and verification? How does validation and verification fit into the wider context of the IEC 61511 lifecycle? What level of independence is required for validation and verification? The paper will also attempt to provide a practical example of how to implement an effective validation and verification strategy into an overall Functional Safety Plan to give the reader a clearer understanding of the obligations toward demonstrating compliance.


2014 ◽  
Vol 567 ◽  
pp. 271-276
Author(s):  
V. John Kurian ◽  
M.C. Voon ◽  
Mohamed Mubarak Abdul Wahab ◽  
N.A. Iskandar ◽  
Mohd Shahir Liew

Reliability is one major concern in the Oil and Gas industry to date. Reliability issues due to aging and increasing environmental loading are common for jacket platforms in Malaysia. Authors have studied system reliability assessment on existing jacket platforms in Malaysian waters and concluded that the current reliability assessment in the industry practice is tedious. The scope of the study includes regression analysis using three different methods to generate regression equation which could serve as a simplified reliability prediction model. Regression equations generated in this study seek to improve the current reliability assessment of jacket platforms in Malaysia by providing means for screening process before proceeding to tedious reliability analysis.


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