Instrument Safety Valves Enhanced Maintenance Strategy

2021 ◽  
Author(s):  
Yahya Hamood Al Naumani ◽  
Abdul Aziz Ahmed Al Abri ◽  
Mahmood Ahmed Al Ruqaishi

Abstract Emergency Shutdown (ESD) and Blowdown (BDV) valves are the final elements part of the Safety Instrumented Functions (SIF) in which are deployed in oil and gas assets. They are classified as safety critical equipment to prevent major accident hazards. The conventional method of proof testing these valves is to close/open them fully, and thus require a process shutdown. In general, planned process shutdown is only viable every two to four years. Such infrequent and limited tests lead to imperfect testing and degrade the reliability of safety instrumented functions. Accordingly, this paper presents the work done to develop a comprehensive maintenance strategy that addresses lifecycle management of safety instrumented function in operate phase which help reduce the potential of process safety incidents. In summary, the innovative approach presented by this paper offers best practice of safety critical system integrity management implementation to achieve the highest standards of operational excellence.

Author(s):  
Dave Metzger

Holistic asset management aimed at all aspects of improved safety and business performance has identified poor bolt tightening as a major cause of leaks, thereby raising the need for understanding the concept of joint integrity and in particular the requirement to apply more control throughout this often overlooked process. The UK government’s Health and Safety Executive has reported on industry poor practice in offshore oil and gas applications, and working with the United Kingdom Offshore Operators Association (UKOOA) has produced guidelines and recommendations for the reduction of hydrocarbon leaks from bolted joints. This recommended safe practice, the lessons learnt and the guidelines made are equally applicable to the power generation industry and in particular the nuclear one. The goals of leak free assembly, failure reduction and the elimination of wasted time and effort are achieved through the use of a risk based approach and the implementation of industry best practice. Building on experience learnt from the petrochemical industry: - this paper will provide guidelines relevant to the nuclear power generation industry for leak avoidance using risk assessment methods and competency management to establish the principles of a Joint Integrity Management System and highlight best industrial practice.


Author(s):  
Shahani Kariyawasam ◽  
Warren Peterson

Reliability methods have being adopted by oil and gas operators for integrity management decisions. These methods explicitly account for all relevant uncertainties and are designed to provide consistent safety. Consequently, a risk or reliability based approach is a very appropriate basis for decision making in the face of uncertainties. However, as in the effective use of any powerful methodology the sensitivities of the method to assumptions and limitations of applicability need to be well understood. This paper presents how improvements were made to reliability based integrity program by understanding its limitations and sensitivities. First the inputs that have the highest impact on the results were identified. These inputs are the most appropriate areas for improvement and data gathering. It is also very important to understand how the results are to be used and for what purpose. The results of this particular inline inspection based reliability assessment are used to make better excavation and repair decisions. A defect-based and joint-based decision making process is essential for determining with sufficient confidence if each defect and joint is in a safe condition. Consequently, the improvements are focused on discriminating between the myriad of defects found during an inline inspection run. Distinct field characteristics of corrosion growth are also taken into account in these improvements. The paper presents the implementation of effective area methods for future integrity probabilistic evaluations. It also describes the benefit of applying defect-specific growth rates. Finally, case studies are presented to demonstrate the effectiveness of the changes.


Author(s):  
Karine Kutrowski ◽  
Rob Bos ◽  
Jean-Re´gis Piccardino ◽  
Marie Pajot

On January 4th 2007 TIGF published the following invitation for tenders: “Development and Provision of a Pipeline Integrity Management System”. The project was awarded to Bureau Veritas (BV), who proposed to meet the requirements of TIGF with the Threats and Mitigations module of the PiMSlider® suite extended with some customized components. The key features of the PiMSlider® suite are: • More than only IT: a real integrity philosophy, • A simple intuitive tool to store, display and update pipeline data, • Intelligent search utilities to locate specific information about the pipeline and its surrounding, • A scalable application, with a potentially unlimited number of users, • Supervision (during and after implementation) by experienced people from the oil and gas industry. This paper first introduces TIGF and the consortium BV – ATP. It explains in a few words the PIMS philosophy captured in the PiMSlider® suite and focuses on the added value of the pipeline Threats and Mitigations module. Using this module allows the integrity analyst to: • Prioritize pipeline segments for integrity surveillance purposes, • Determine most effective corrective actions, • Assess the benefits of corrective actions by means of what-if scenarios, • Produce a qualitative threats assessment for further use in the integrity management plan, • Optimize integrity aspects from a design, maintenance and operational point of view, • Investigate the influence of different design criteria for pipeline segments. To conclude, TIGF presents the benefits of the tool for their Integrity Management department and for planning inspection and for better knowledge of their gas transmission grid.


2014 ◽  
Author(s):  
K.. Francis-LaCroix ◽  
D.. Seetaram

Abstract Trinidad and Tobago offshore platforms have been producing oil and natural gas for over a century. Current production of over 1500 Bcf of natural gas per year (Administration, 2013) is due to extensive reserves in oil and gas. More than eighteen of these wells are high-producing wells, producing in excess of 150 MMcf per day. Due to their large production rates, these wells utilize unconventionally large tubulars 5- and 7-in. Furthermore, as is inherent with producing gas, there are many challenges with the production. One major challenge occurs when wells become liquid loaded. As gas wells age, they produce more liquids, namely brine and condensate. Depending on flow conditions, the produced liquids can accumulate and induce a hydrostatic head pressure that is too high to be overcome by the flowing gas rates. Applying surfactants that generate foam can facilitate the unloading of these wells and restore gas production. Although the foaming process is very cost effective, its application to high-producing gas wells in Trinidad has always been problematic for the following reasons: Some of these producers are horizontal wells, or wells with large deviation angles.They were completed without pre-installed capillary strings.They are completed with large tubing diameters (5.75 in., 7 in.). Recognizing that the above three factors posed challenges to successful foam applications, major emphasis and research was directed toward this endeavor to realize the buried revenue, i.e., the recovery of the well's potential to produce natural gas. This research can also lead to the application of learnings from the first success to develop treatment for additional wells, which translates to a revenue boost to the client and the Trinidad economy. Successful treatments can also be used as correlations to establish an industry best practice for the treatment of similarly completed wells. This paper will highlight the successes realized from the treatment of three wells. It will also highlight the anomalies encountered during the treatment process, as well as the lessons learned from this treatment.


Kerntechnik ◽  
2021 ◽  
Vol 86 (5) ◽  
pp. 343-352
Author(s):  
J. Cui ◽  
Y. Cai ◽  
Y. Wu

Abstract Software criticality analysis examines the degree of contribution that each individual failure mode of a software component has on the reliability of software. Higher safety integrity levels are assigned to software modules whose failures cause an unacceptable impact on the operation of the system, and these levels require the implementation of more rigorous software quality assurance measures as defined in IEEE Std 1012 and in the customer’s system requirements specification. In this paper, a novel software criticality analysis method is proposed, the results of which can be used to guide the development of newly developed software and the procurement of Commercial-Off-The-Shelf (COTS) software. The software structure is first analyzed and the software is divided into modules according to their functions. Then the criticality levels of software components are preliminarily classified by means of a safety criticality preliminary analysis tree, followed by their verification through the software hazard and operability analysis (HAZOP). Finally, the target Safety Integrity Level (SIL) of each software module is determined based on its criticality level and the overall safety objective (i. e., SIL) of the system it resides in. As an example, this proposed method is applied to a nuclear power plant safety-critical system to demonstrate the detail application process and to verify the feasibility of the method. Compared with the existing software criticality analysis methods, this method has better operability and verifiability, and can be utilized as a technical guidance for the software criticality analysis of nuclear power plant digital control systems.


Author(s):  
Terry Griffiths ◽  
Scott Draper ◽  
Liang Cheng ◽  
Feifei Tong ◽  
Antonino Fogliani ◽  
...  

As offshore renewable energy projects progress from concept demonstration to commercial-scale developments there is a need for improved approaches beyond conventional cable engineering design methods that have evolved from larger diameter pipelines for the oil and gas industry. New approaches are needed to capture the relevant physics for small diameter cables on rocky seabeds to reduce the costs and risks of power transmission and increase operational reliability. This paper reports on subsea cables that MeyGen installed for Phase 1a of the Pentland Firth Inner Sound tidal stream energy project. These cables are located on rocky seabeds in an area where severe metocean conditions occur. ROV field observation of these cables shows them to be stable on the seabed with little or no movement occurring over almost all of the cable routes, despite conventional engineering methods predicting significant dynamic movement. We cite recent research undertaken by the University of Western Australia (UWA) to more accurately assess the hydrodynamic forces and geotechnical interaction of cables on rocky seabeds. We quantify the conformity between the cables and the undulating rocky seabed, and the distributions of cable-seabed contact and spanning via simulations of the centimetric-scale seabed bathymetry. This analysis leads to calculated profiles of lift, drag and seabed friction along the cable, which show that all of these load and reaction components are modelled in an over-conservative way by conventional pipeline engineering techniques. Overall, our analysis highlights that current cable stability design can be unnecessarily conservative on rocky seabeds. Our work foreshadows a new design approach that offers more efficient cable design to reduce project capex and enhance through-life integrity management.


Author(s):  
Amitabh Kumar ◽  
Brian McShane ◽  
Mark McQueen

A large Oil and Gas pipeline gathering system is commonly used to transport processed oil and gas from an offshore platform to an onshore receiving facility. High reliability and integrity for continuous operation of these systems is crucial to ensure constant supply of hydrocarbon to the onshore processing facility and eventually to market. When such a system is exposed to a series of complex environmental loadings, it is often difficult to predict the response path, in-situ condition and therefore the system’s ability to withstand subsequent future loading scenarios. In order to continue to operate the pipeline after a significant environmental event, an overall approach needs to be developed to — (a) Understand the system loading and the associated integrity, (b) Develop a series of criteria staging the sequence of actions following an event that will verify the pipeline integrity and (c) Ensure that the integrity management solution is simple and easy to understand so that it can be implemented consistently. For a complex loading scenario, one of the main challenges is the ability to predict the controlling parameter(s) that drives the global integrity of these systems. In such scenarios, the presence of numerous parameters makes the technical modeling and prediction tasks arduous. To address such scenarios, first and foremost, it is crucial to understand the baseline environment data and other associated critical design input elements. If the “design environmental baseline” has transformed (due to large events e.g. storms etc.) from its original condition; it modifies the dynamics of the system. To address this problem, a thorough modeling and assessment of the in-situ condition is essential. Further, a robust calibration method is required to predict the future response path and therefore expected pipeline condition. The study further compares the planned integrity management solutions to the field data to validate the efficiency of the predicted scenarios. By the inclusion of real field-data feedback to the modeling method, balanced integrity solutions can be achieved and the ability to quantify the risks is made more practical and actionable.


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