Integrity Management and Life Extension for a CALM Buoy Oil Export Terminal

Author(s):  
Robert B. Gordon ◽  
Juan Carlos Ruiz-Rico ◽  
Michiel Peter Hein Brongers ◽  
Julian Gomez

This paper applies state-of-the-art integrity management and life extension methodologies to address degradation and failure modes specific to CALM buoy export terminals. The main objectives are to (1) classify the components of the export terminal according to their criticality, (2) establish risk-based inspection and maintenance plans to reduce or mitigate risk to acceptable levels and (3) assess remaining life. The method is applied to a CALM buoy operating off the coast of Colombia. This buoy serves as the oil export terminal for all crude oil transmitted by the Ocensa pipeline, which has a capacity of 560 kBPD or around 60% of total Colombia oil production. The buoy is nearing the end of its design life, and options for life extension have been investigated based on an integrity assessment of the current condition of the equipment. As part of the assessment, detailed plans for future Risk Based Inspections (RBI) and Mitigation, Intervention, and Repair (MIR) have been developed.

Author(s):  
Hao Song ◽  
Chenteh Alan Yu ◽  
Yongming Cheng ◽  
Jing Hou

Abstract The riser is a critical element in a subsea production system for transporting hydrocarbons from the seafloor to the surface. The track record of existing riser systems worldwide has shown that risers tend to be designed conservatively to accommodate dynamic loads, strength and fatigue requirements, and corrosion/erosion provision needs. Among all the riser types, the steel catenary riser (SCR) is the most installed riser configuration for deepwater oil and gas production worldwide in the last two decades. This is mainly because of their simple configuration and relatively low manufacturing and installation cost. As riser technology advances, SCRs are designed to tackle more challenging environments and longer service lives. For the riser life extension applications, regulatory bodies prefer riser operations to be managed through an integrity management program, demonstrating that a robust framework with detailed records on the conditions of the risers is in place. This paper studies an integrity management program for SCRs with a 30-year design life in a harsh environment. The planned riser integrity management program is based on successful industry practice and the newly published riser integrity management standard API RP 2RIM [4]. It starts with a review of the riser design basis and as-built data, continuing with key field data measurement and production fluid sampling. A digital model, continuously calibrated with the measured data, is established to assess the integrity of the riser system. Key physical quantities are selected to monitor the structural health of the SCRs, including vessel motion measurement, measurement of SCR top hang-off angles and tensions, and full water column current measurement. The relationship between the measurement data and the riser strength and fatigue performance is established. Details of the riser integrity assessment in a digital model utilizing the measurement data are presented. The implemented proposed riser integrity management program is expected to provide a more focused and efficient method with a higher level of confidence in operating the SCRs during the design life and potentially beyond.


Author(s):  
Abe Nezamian ◽  
Joshua Altmann

The ageing of offshore infrastructure presents a constant and growing challenge for operators. Ageing is characterised by deterioration, change in operational conditions or accidental damages which, in the severe operational environment offshore, can be significant with serious consequences for installation integrity if not managed adequately and efficiently. An oil field consisting of twelve well head platforms, a living quarter platform (XQ), a flare platform (XFP) and a processing platform (XPA) are the focus of this paper, providing an overview of the integrity assessment process. In order to ensure technical and operational integrity of these ageing facilities, the fitness for service of these offshore structures needs to be maintained. Assessments of the structural integrity of thirteen identified platforms under existing conditions were undertaken as these platforms are either nearing the end of their design life or have exceeded more than 50% of their design life. Information on history, characteristic data, condition data and inspection results were collected to assess the current state and to predict the future state of the facility for possible life extension. The information included but was not limited to as built data, brown fields modifications, additional risers and clamp-on conductors and incorporation of subsea and topside inspection findings. In-service integrity assessments, pushover analyses, corrosion control and cathodic protection assessments and weight control reports were completed to evaluate the integrity of these facilities for requalification to 2019 and life extension to 2030. The analytical models and calculations were updated based on the most recent inspection results and weight control reports. A requalification and life extension report was prepared for each platform to outline the performance criteria acceptance to achieve requalification until 2019 and life extension until 2030. This paper documents the methodology to assess the platform structural integrity in order to evaluate platform integrity for the remaining and extended design life. An overview of various aspects of ageing related to these offshore facilities, representing risk to the integrity, the required procedures and re assessment criteria for deciding on life extension of these facilities is presented. This paper also provides an overall view of the structural requirements, justifications and calibrations of the original design for the life extension to maintain the safety level by means of maintenance and inspection programs balancing the ageing mechanisms and improving the reliability of assessment results.


1989 ◽  
pp. 1-20

Abstract The ability to accurately assess the remaining life of components is essential to the operation of plants and equipment, particularly those in service beyond their design life. This, in turn, requires a knowledge of material failure modes and a proficiency for predicting the near and long term effects of mechanical, chemical, and thermal stressors. This chapter presents a broad overview of the types of damage to which materials are exposed at high temperatures and the approaches used to estimate remaining service life. It explains how operating conditions in power plants and oil refineries can cause material-related problems such as embrittlement, creep, thermal fatigue, hot corrosion, and oxidation. It also discusses the factors and considerations involved in determining design life, defining failure criteria, and implementing remaining-life-assessment procedures.


Author(s):  
G. Sigurdsson ◽  
T. Hørte ◽  
M. Macke ◽  
A. Wormsen ◽  
L. Reinås

Abstract Subsea Wellheads are the male part of an 18 3/4” bore connector used for connecting subsea components such as drilling BOP, XT or Workover systems equipped with a female counterpart — a wellhead connector. Subsea wellheads have an external locking profile for engaging a preloaded wellhead connector with matching internal profile. When the connector is locked subsea a metal-to-metal sealing is obtained and a structural conduit is formed. The details of the subsea wellhead profile are specified by the wellhead user and the standarisedH4 hub has a widespread use. In terms of well integrity, the wellhead connector is a barrier element during both well construction (drilling) activities and life of field (production). Due to the nature of subsea drilling operations a wellhead connector will be subjected to external loads. Fatigue and plastic collapse are therefore two potential failure modes. These two failure modes are due to the cyclic nature of the loads and the potential for accidental and extreme single loads respectively. Establishing the safe load level that the wellhead connector has structural capacity to handle without failure can be done by deterministic engineering methods. Similarly, a deterministic calculated safe fatigue life is the use limit preventing fatigue failure, assuming no inspections. Probabilistic engineering method; Structural Reliability Analysis (SRA), can be applied to a subsea wellhead connector to establish the probability of fatigue failure (PoF). Risk Based Inspection (RBI) is a probabilistic analysis procedure that requires quantified PoF and Consequence of Failure (CoF). The RBI outcome may be used to optimized inspection plans to ensure a safe PoF target level. The RBI methodology is widely accepted, and guidance can be found in several standards. Subsea wellheads are normally classified as un-inspectable. During drilling operations commencement, the uppermost section of the wellhead (high pressure housing including H4 hub profile) will be visible and accessible thus allowing for inspection. This uppermost section may also accessible for inspection when a wellhead connector is locked on. From an SRA basis a generic RBI procedure applicable to subsea wellheads are proposed and established for a generic case of a 27” mandrel with a H4 hub. This paper then proceeds to providing the maximum non detectable flaw size performance required for a wellhead inspection tool/method to be efficient. The importance of accidental load and cyclic load magnitude and uncertainty is shown to impact this conclusion. The potential inspectional value of performing BOP connector leak test at regular intervals during the drilling operation has also been investigated and shown to be conditionally limited. This paper proposes a procedure for application of RBI to the problem of achieving life extension of a wellhead external locking profile while connected to a wellhead connector. The objective is to propose minimum performance requirements for the inspection tool/method to be efficient. Finally, the potential impact of RBI results in a well integrity risk assessment is covered.


Author(s):  
Andrew Francis ◽  
Mike Gardiner ◽  
Marcus McCallum

Pipeline designers and operators recognize that the commercial viability of operating high-pressure gas pipelines decreases with time. This is because the structural integrity levels of the pipeline decrease, due to the action of deterioration processes such as corrosion and fatigue, until the level of mitigation required to ensure adequate safety levels becomes uneconomical. For this reason pipelines are assigned a nominal design life of typically 40 years. This paper describes the application of structural reliability analysis to a high-pressure natural gas pipeline having both onshore and offshore sections, in order to determine the extent to which the asset life could be increased beyond the design life without any significant reduction in reliability and hence safety levels. The approach adopted was to identify the credible failure modes that could affect each of the onshore and offshore sections and determine the probability of failure due to each failure mode taking account of the uncertainties in the parameters that affect each mode. Based on a detailed consideration of the results of the study it was concluded that the life of the asset considered here could be extended to 60 years without any significant reduction in safety levels. Moreover, it was concluded that if certain mitigating measures were to be implemented in the future then it would be possible to increase the asset life to significantly more than 60 years.


Author(s):  
A. Stacey ◽  
M. Birkinshaw ◽  
J. V. Sharp

With many offshore installations in the UK sector of the North Sea now reaching or being in excess of their original anticipated design life, there is a particular need to evaluate approaches to structural integrity management by offshore operators. Ageing processes can affect the structural integrity of the installation and demonstration of adequate performance beyond its original design life is thus a necessary requirement. This paper addresses the issues relevant to the life extension of ageing installations.


Author(s):  
Adriana Botto ◽  
Enda O’Sullivan ◽  
Ce´line Banti

The population of flexible pipes is increasing exponentially and by definition it is ageing. Over the coming years an increasing number of flexible pipes will reach the end of their design life, therefore prudent operators should focus on understanding the integrity status of their flexible pipes. Understanding and effectively managing the integrity of flexible pipes is necessary to prevent, predict, or detect the presence of any loss of integrity. A detailed understanding of the manufacturing history, operational conditions, any previous repairs and inspection or test history are all required to gain a full insight of the flexible pipe fitness and assess its suitability for continued operation and for any potential life extension beyond the initially intended service life. This paper presents guidelines for developing and implementing an integrity management strategy, which utilises the correct mix of inspection and assessment tools (degradation of internal pressure sheath, fatigue assessment, corrosion and annulus condition monitoring etc.) and operating procedures that will allow the operator to assess the opportunity for life extension of flexible pipes.


2015 ◽  
Vol 55 (2) ◽  
pp. 414
Author(s):  
Brian Humphreys ◽  
Wacek Lipski

The Australian oil and gas boom of the 1960s and 1970s lead to production commencing in the Gippsland, Surat, Cooper and Carnarvon basins and so many pipeline assets around Australia are approaching operating lives of 40-50 years and the end of their design lives. With unconventional field development and the Australian gas markets opening up to international customers through LNG, there will be an increasing requirement to extend the life of pipelines while maintaining safety and integrity. The management of pipeline assets late in their design life is a challenge for operators both onshore and offshore, with pipelines requiring higher levels of inspection and maintenance, while revenues can be fixed or regulated for downstream assets or potentially declining for upstream assets. To operate pipelines beyond their specified design life, there are requirements that must be fulfilled—for offshore, a design re-qualification in accordance with DNV-OS-F101 and for onshore, a remaining life review in accordance with AS2885.3. In addition, for onshore pipelines, AS2885.3 requires the remaining life review process to be undertaken every 10 years, rather than just at the end of the design life. This extended abstract discusses the requirements of the DNV-OS-F101 and AS2885.3 and the approaches required to meet these requirements. It also discusses key lessons that have been learned and makes recommendations to pipeline operators preparing for end-of-design-life reviews and executing them as cost effectively as possible.


Author(s):  
Jens P. Tronskar

Cost efficient offshore field development often involves tiebacks to existing field infrastructure. Efficient field development requires life extension of existing production facilities and pipelines to accommodate the new field resources over their life expectation. For fields near the tail end of their production the pipelines may be close to the end of their design life, and it must be shown that they have potential for extended life beyond the original design life until the end of the period of operation of the new field. Offshore pipelines are designed and constructed to recognized standards, such as the widely applied DNV OS-F101 2013 Submarine Pipelines Systems and earlier versions. The latest edition of the code was recently issued as a standard with some major updates and a modified code number i.e. DNVGL ST-F101 [1]. As pipelines age, they will inevitably be exposed to various types of degradation and an Operator must be able to both assess the significance of this damage and the pipeline remaining life to ensure that the pipelines do not fail as they age before the end of their design lives. Currently, many pipelines are operated far beyond the original design life and as mentioned above for cost efficient field development the pipeline operator often needs to demonstrate that the pipeline’s useful life can be extended another 10 or in some cases up to 30 years. For some pipelines, new operating conditions will be introduced by tie-in of new fields and this will impact the future rate of degradation. Hence, it cannot be assumed that the future degradation will be similar or less severe than experienced since commissioning of the pipeline. Extension of the life of the pipeline can be demonstrated by adopting methods of analysis that show the line is safe for an extended life under the future expected operating condition. This paper describes the risk based approach applied for pipeline remaining life and life extension analyses based on DNV GL codes and other relevant recommended practices. For illustration of the methodology a typical case of remaining life assessment of and life extension of a gas export pipeline is presented in the Case Study.


Author(s):  
Shailesh Javia

Integrity management of pipelines is a systematic, comprehensive and integrated approach to proactively counter the threats to pipeline integrity. Pressure testing, in-line inspection and direct assessment methods are used to verify the integrity of a buried pipeline. The Paper Discuses Direct Assessment Methodologies for Hydrocarbon Non Piggable Pipelines. Advantages and Disadvantages of Direct Assessment methodology and DA Protocols. The DA process accomplishes this by utilizing and integrating condition monitoring, effective mitigation, meticulous documentation and timely structured reporting processes. DA is a structured, iterative integrity assessment process through which an operator may be able to assess and evaluate the integrity of a pipeline segment. TIME DEPENDENT THREATS INEVITABLY LED TO NUMEROUS FAILURES WITH A COMMON DEFINING MECHANISM OR SOURCE – CORROSION. This Paper will focus on internal, external and stress corrosion cracking direct assessment along with pre and post assessment, quality assurance, data analysis and integration, and remediation and mitigation activities. This paper will discuss some of the regulatory requirements for Pipeline Integrity Management System.


Sign in / Sign up

Export Citation Format

Share Document