Life-Extension Project Applies Assessment of Reinforced Concrete to Nonjacket Structures

2021 ◽  
Vol 73 (09) ◽  
pp. 53-54
Author(s):  
Chris Carpenter
Keyword(s):  
Reinforced Concrete ◽  
Oil And Gas ◽  
Environmental Data ◽  
Life Extension ◽  
Offshore Technology ◽  
Oil Storage ◽  
Safety Case ◽  
Jacket Structures ◽  
Advanced Analysis ◽  
Critical Components

This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper OTC 31250, “Wandoo B: Application of Advanced Reinforced Concrete Assessment for Life Extension for Non-Jacket Structures,” by Robert Sheppard, Spire Engineering; Colin O’Brien, Vermilion Oil and Gas; and Yashar Moslehy, Spire Engineering, et al., prepared for the 2021 Offshore Technology Conference, originally scheduled to be held in Houston, 4–7 May. The paper has not been peer reviewed. Copyright 2021 Offshore Technology Conference. Reproduced by permission. Wandoo B is a concrete gravity-based structure (GBS) and is the main production facility for the Wandoo field offshore northwest Australia. It was installed in 1997 with a design life of 20 years. The structural assessments discussed in this paper are part of a comprehensive life-extension project encompassing wells, subsea systems, marine and safety systems, and topsides facilities and structures to demonstrate fitness for service through the end of field life. Background The GBS serves as the support structure for the Wandoo B facility and provides oil storage for the Wandoo field. The structure has four shafts approximately 11 m in diameter that support the top-sides facilities and a base structure with permanent ballast and oil storage cells (Fig. 1). It was originally developed as an ExxonMobil-led project and now is owned and operated wholly by Vermilion Oil and Gas Australia. The reinforced concrete (RC) shafts and the base top slab are pretensioned. In the shafts, tendons are enclosed in 20 ducts distributed around the circumference. The top of the shafts provides a mating point with the steel topsides structure with the connection formed by embedded anchor bolts in a bulge in the shaft cross section. The topsides structure is a three-level braced steel frame system supporting production operations for 12 well conductors contained within the northeast shaft and three outboard well conductors. Life-Extension Project The facility was designed with a target life of 20 years. The life-extension project was intended not only to satisfy the operator’s responsibility to continue safe operations and adhere to their safety case but also to meet the expectations of the regulator. The structural aspects of the project included four phases, the first two of which are detailed in this synopsis: - Design assessments per latest standards and modifications where required - Ultimate capacity assessments with retrofit modifications where required - Risk studies and workshops to demonstrate that risk is as low as reasonably practicable (ALARP) - Integrity-management manual and inspection plan The first two phases were addressed using the latest condition-assessment, weight, and environmental data available. The phased approach allowed the assessment team to use basic linear approaches to demonstrate code compliance and only use the more-advanced analysis techniques to evaluate the critical components that did not satisfy code or were needed to provide input to the ALARP assessment and establish target reliability for the facility.

Wandoo B: Application of Advance Reinforced Concrete Assessment for Life Extension for Non-Jacket Structures

2021 ◽  
Author(s):  
Robert Sheppard ◽  
Colin O’Brien ◽  
Yashar Moslehy ◽  
Rachel Roberts
Keyword(s):  
Reinforced Concrete ◽  
Nonlinear Behavior ◽  
Steel Structure ◽  
Life Extension ◽  
Equivalent Model ◽  
Original Design ◽  
Oil Storage ◽  
Jacket Structures ◽  
Tension And Compression ◽  
Main Production

Abstract Wandoo B is a concrete Gravity Base Structure (GBS) and is the main production facility for the Wandoo field offshore NW Australia. It was installed in 1997 with a design life of 20 years. The structural assessments discussed in this paper are part of a comprehensive life extension project encompassing wells, subsea systems, marine and safety systems, topsides facilities and structures to demonstrate fitness for service through the end of field life (EOFL). The challenge was to demonstrate compliance efficiently and effectively for a large structure with a range of materials (steel, reinforced concrete (RC)) and operations supported (oil storage, drilling, production) under increased loading criteria compared to the original design. There is comprehensive industry guidance for assessing existing steel jacket structures, but far less for a concrete GBS such as Wandoo B. Demonstrating compliance required a combination of computer model results, project-specific tools to check reinforced concrete sections, and engineering judgement to define how much damage constitutes failure. A number of global and local structural models were developed to assess the linear and nonlinear performance of the reinforced concrete and steel structure. A phased approach was employed using basic, conservative approaches in initial phases to demonstrate code compliance, and progressing to more advanced, less conservative approaches for those components under higher stress. Developing models that more accurately simulate the behavior of the different structural components and materials was a large part of the project scope, particularly for the nonlinear behavior of the reinforced concrete and the interface connections between the steel and reinforced concrete structures. It was inefficient to develop a detailed steel and reinforced concrete solid model of the large GBS shafts and base, so an equivalent shell model was developed and tested to determine the global behavior and onset of damage. This equivalent model aimed to predict behavior accurately for metocean and seismic loads under material tension and compression. Local detailed models were then developed including a constitutive model of reinforced concrete and used to define the extent of the damage and predict where failure would occur.

Structural Impact in FPSO Life Extension: A Class Perspective

2013 ◽  
Author(s):  
Christiane L. Machado ◽  
Sudheer Chand
Keyword(s):  
Service Life ◽  
Oil And Gas ◽  
Structural Response ◽  
Oil And Gas Industry ◽  
Environmental Data ◽  
Life Extension ◽  
Element Analysis ◽  
Actual Performance ◽  
Remaining Service Life ◽  
The Impact

The Offshore Oil and Gas Industry has converted a large number of units from trading tankers and carriers into Floating Production, Storage and Offloading units (FPSOs). Several of these have been moored offshore Brazil during the last 15 years. Following the discovery of offshore pre-salt fields some years ago, demand for FPSOs has increased, and the forecasts for productive field lives have grown. The result of these developments is the need to extend the service lives of existing FPSOs. The main aim of this study is to investigate FPSO structural response to environmental conditions and functional loads, considering the actual available tools for numerical simulations and Rule requirements, which currently are basic requirements for design review for Classification. The procedure was developed from one selected FPSO converted from a trading Very Large Crude Carrier (VLCC) tanker approximately 15 years ago and includes investigation of the impact on hull behavior comparing the motion analyses of the production unit under environmental data and software capabilities available at the period of conversion and actual performance: variances in the environmental (sea scatter diagrams) datasets; updates to Classification requirements for defining offloading conditions, environmental loads, acceptance criteria and remaining fatigue life (RFL); and incorporating the most recent gauged thickness for primary structure. The selected FPSO was evaluated according to prescriptive Rule requirements and also using finite element analysis, taking into account the previous conditions of Classification approval as well as the actual requirements and available data. Structural analysis included one global model and some local refined models to address strength, buckling and fatigue capacity of the typical portions/connections of the hull. The comparisons performed from the results of these analyses are a crucial step toward understanding the structural capacity of the FPSO at the conversion stage, its performance during the last 15 years, and its remaining service life. Differences were tabulated and evaluated so that a more precise level of uncertainty could be achieved for predicting the estimated remaining service life, and consequently, a new and dedicated approach to investigate the existing FPSO fleet is being generated.

Field Implementation of RBI for Jacket Structures

2003 ◽  
Author(s):  
Michael H. Faber ◽  
Daniel Straub ◽  
John D. So̸rensen ◽  
Jesper Tychsen
Keyword(s):  
Sensitivity Analysis ◽  
Data Base ◽  
Stress Ratio ◽  
Oil And Gas ◽  
Inspection Planning ◽  
The North ◽  
Large Numbers ◽  
Structural Details ◽  
Jacket Structures ◽  
The North Sea

The present paper first gives a brief outline of the simplified and generic approach to reliability and risk based inspection planning and thereafter sets focus on a recent application of the methodology for planning of in-service NDT inspections of the fixed offshore steel jacket structures in the DUC concession area in the Danish part of the North-Sea. The platforms are operated by Maersk Oil and Gas on behalf of DUC partners A.P. Mo̸ller, Shell and Texaco. The study includes a sensitivity analysis performed for the identification of relevant generic parameters such as the bending to membrane stress ratio, the design fatigue life and the material thickness. Based on the results of the sensitivity analysis a significant number of inspection plans were computed for fixed generic parameters (pre-defined generic plans) and a data-base named iPlan was developed from which inspection plans may be obtained by interpolation between the pre-defined generic plans. The iPlan data-base facilitates the straightforward production of large numbers of inspection plans for structural details subject to fatigue deterioration. In the paper the application of the generic inspection plan database iPlan is finally illustrated on an example.

Digital Deployment Lessons From Early Adopters

2021 ◽  
Vol 73 (05) ◽  
pp. 52-53
Author(s):  
Judy Feder
Keyword(s):  
Data Privacy ◽  
Business Models ◽  
Oil And Gas ◽  
Local Level ◽  
Digital Transformation ◽  
Automotive Manufacturing ◽  
Early Adopters ◽  
Offshore Technology ◽  
Offshore Oil And Gas ◽  
Offshore Oil

This article, written by JPT Technology Editor Judy Feder, contains highlights of paper OTC 30794, “Digitalization Deployed: Lessons Learned From Early Adopters,” by John Nixon, Siemens, prepared for the 2020 Offshore Technology Conference, originally scheduled to be held in Houston, 4–7 May. The paper has not been peer reviewed. Copyright 2020 Offshore Technology Conference. Reproduced by permission. With full-scale digital transformation of oil and gas an inevitability, the industry can benefit by examining the strategies of industries such as automotive, manufacturing, marine, and aerospace that have been early adopters. This paper discusses how digital technologies are being applied in other verticals and how they can be leveraged to optimize life-cycle performance, drive down costs, and decouple market volatility from profitability for offshore oil and gas facilities. Barriers to Digital Adoption Despite the recent dramatic growth in use of digital tools to harness the power of data, the industry as a whole has remained conservative in its pace of digital adoption. Most organizations continue to leverage technology in disaggregated fashion. This has resulted in an operating environment in which companies can capture incremental inefficiencies and cost savings on a local level but have been largely unable to cause any discernible effect on operating or business models. Although the recent market downturn constrained capital budgets significantly, an ingrained risk-averse culture is also to blame. Other often-cited reasons for the industry’s reluctance to digitally transform include cost of downtime, cyber-security and data privacy, and limited human capital. A single offshore oil and gas facility failure or plant trip can result in millions of dollars in production losses. Therefore, any solution that has the potential to affect a process or its safety negatively must be proved before being implemented. Throughout its history, the industry has taken a conservative approach when adopting new technologies, even those designed to prevent unplanned downtime. Although many current technologies promise increases of 1 to 2% in production efficiency, these gains become insignificant in the offshore industry if risk exists that deployment of the technology could in any way disrupt operations. Cybersecurity and data privacy are perhaps the most-significant concerns related to adoption of digital solutions by the industry, and they are well-founded. Much of today’s offshore infrastructure was not designed with connectivity or the Internet of Things in mind. Digital capabilities have simply been bolted on. In a recent survey of oil and gas executives, more than 60% of respondents said their organization’s industrial control systems’ protection and security were inadequate, and over two-thirds said they had experienced at least one cybersecurity attack in the previous year. Given this reality, it is no surprise that offshore operators have been reluctant to connect their critical assets. They are also cautious about sharing performance data with vendors and suppliers. This lack of collaboration and connectivity has inevitably slowed the pace of digital transformation, the extent to which it can be leveraged, and the value it can generate.

Technology Focus: Offshore Facilities (September 2021)

2021 ◽  
Vol 73 (09) ◽  
pp. 50-50
Author(s):  
Ardian Nengkoda
Keyword(s):  
Oil And Gas ◽  
Energy Transition ◽  
Oil Price ◽  
Low Carbon ◽  
The Past ◽  
Offshore Technology ◽  
Net Zero ◽  
Offshore Oil And Gas ◽  
Offshore Oil ◽  
Low Carbon Energy

For this feature, I have had the pleasure of reviewing 122 papers submitted to SPE in the field of offshore facilities over the past year. Brent crude oil price finally has reached $75/bbl at the time of writing. So far, this oil price is the highest since before the COVID-19 pandemic, which is a good sign that demand is picking up. Oil and gas offshore projects also seem to be picking up; most offshore greenfield projects are dictated by economics and the price of oil. As predicted by some analysts, global oil consumption will continue to increase as the world’s economy recovers from the pandemic. A new trend has arisen, however, where, in addition to traditional economic screening, oil and gas investors look to environment, social, and governance considerations to value the prospects of a project and minimize financial risk from environmental and social issues. The oil price being around $75/bbl has not necessarily led to more-attractive offshore exploration and production (E&P) projects, even though the typical offshore breakeven price is in the range of $40–55/bbl. We must acknowledge the energy transition, while also acknowledging that oil and natural gas will continue to be essential to meeting the world’s energy needs for many years. At least five European oil and gas E&P companies have announced net-zero 2050 ambitions so far. According to Rystad Energy, continuous major investments in E&P still are needed to meet growing global oil and gas demand. For the past 2 years, the global investment in E&P project spending is limited to $200 billion, including offshore, so a situation might arise with reserve replacement becoming challenging while demand accelerates rapidly. Because of well productivity, operability challenges, and uncertainty, however, opening the choke valve or pipeline tap is not as easy as the public thinks, especially on aging facilities. On another note, the technology landscape is moving to emerging areas such as net-zero; decarbonization; carbon capture, use, and storage; renewables; hydrogen; novel geothermal solutions; and a circular carbon economy. Historically, however, the Offshore Technology Conference began proactively discussing renewables technology—such as wave, tidal, ocean thermal, and solar—in 1980. The remaining question, then, is how to balance the lack of capital expenditure spending during the pandemic and, to some extent, what the role of offshore is in the energy transition. Maximizing offshore oil and gas recovery is not enough anymore. In the short term, engaging the low-carbon energy transition as early as possible and leading efforts in decarbonization will become a strategic move. Leveraging our expertise in offshore infrastructure, supply chains, sea transportation, storage, and oil and gas market development to support low-carbon energy deployment in the energy transition will become vital. We have plenty of technical knowledge and skill to offer for offshore wind projects, for instance. The Hywind wind farm offshore Scotland is one example of a project that is using the same spar technology as typical offshore oil and gas infrastructure. Innovation, optimization, effective use of capital and operational expenditures, more-affordable offshore technology, and excellent project management, no doubt, also will become a new normal offshore. Recommended additional reading at OnePetro: www.onepetro.org. SPE 202911 - Harnessing Benefits of Integrated Asset Modeling for Bottleneck Management of Large Offshore Facilities in the Matured Giant Oil Field by Yukito Nomura, ADNOC, et al. OTC 30970 - Optimizing Deepwater Rig Operations With Advanced Remotely Operated Vehicle Technology by Bernard McCoy Jr., TechnipFMC, et al. OTC 31089 - From Basic Engineering to Ramp-Up: The New Successful Execution Approach for Commissioning in Brazil by Paulino Bruno Santos, Petrobras, et al.

Maintaining Technical Integrity of Petroleum Flowlines on Offshore Installations: A Decision Support System for Inspection Planning

2010 ◽  
Author(s):  
R. M. Chandima Ratnayake ◽  
Tore Markeset
Keyword(s):  
Ad Hoc ◽  
Oil And Gas ◽  
Formal Model ◽  
Technical Condition ◽  
Inspection Planning ◽  
Analytic Hierarchy ◽  
Plant Strategy ◽  
The North ◽  
Critical Components ◽  
Inspection Data

Oil and Gas (O&G) platforms in the North Sea are facing aging problems as many of the installations have matured and are approaching their design lifetime. Flowlines are used to transport oil and gas well stream from the wellhead to the production manifold. They are categorised as one of the most critical components on a production facility. Flowline degradation takes place due to corrosion and erosion. The deterioration of a flowline may increase the risk of leakages, ruptures, etc., which shall lead to serious HSE (health, safety and environmental) and financial consequences. Any such risks have a direct impact on the O&G installation’s technical integrity as well as the operator’s sustainability concerns. Conventionally, pipelines are designed with safety provisions to provide a theoretical minimum failure rate over the life span. Furthermore, to reduce the risk of failure various techniques are routinely used to monitor the status of pipelines during the operation phase. The existing methods of flowline health monitoring planning requires one to take into consideration the operator’s plant strategy, flowline degradation mechanisms, historical data, etc. A technical condition report is made based on findings’ reports and degradation trends. This report recommends the inspection of a number of points on the flowlines in a certain year using non-destructive evaluation methods such as visual inspection, ultrasonic testing, radiographic testing, etc. Based on the technical condition report, in general for a certain preventive maintenance shutdown, 10 to 15 flowline inspection openings are accommodated as finance, time and resource availability are taken into consideration. However, it is customary to plan to open more locations in a certain inspection package than can be inspected and minimization of such points is at present done on an ad hoc basis. This paper suggests a formal model and a framework to formally minimize the number of visual inspections by executing the plant strategy as well as HSE concerns. The model is derived using analytic hierarchy process (AHP) framework, which is a multi-criteria decision-making approach. The model is developed based on literature, industrial practice, experience as well as real inspection data from a mature offshore O&G installation located on the Norwegian Continental Shelf.

Construction safety case (MAP) – a strategy for successful implementation

2018 ◽  
Vol 58 (2) ◽  
pp. 601
Author(s):  
Roberta Selleck
Keyword(s):  
Oil And Gas ◽  
Organisational Change ◽  
Field Work ◽  
Construction Safety ◽  
Near Miss ◽  
Successful Implementation ◽  
Operations And Maintenance ◽  
Safety Case ◽  
Operating Limits ◽  
Safety Cases

The Critical Control Management (CCM) methodology has emerged in the construction and mining industries as a ‘safety case’ to manage personal safety risks associated with high-risk activities. The construction-based Major Accident Prevention (MAP) program has been implemented on oil and gas projects since early 2016 and has been tested in greenfields, brownfields, operations and maintenance, and hook-up and commissioning environments. Since implementing the MAP program, a reduction in high potential ‘near miss’ events and a reduction of all injuries has been observed. Within the Clough organisation, four projects that are near completion have zero injuries. MAP works by providing the specific standards (rules), in a similar manner to ‘operating limits’ used in process control systems, to ensure critical control integrity. Through these specific standards, MAP eliminates substandard field work practices becoming normalised and MAP empowers field supervisors and even line employees to ‘stop work’ when critical control standards are not met in the field. Based on widely accepted organisational change principles, a framework for successfully implementing CCM has been developed. The framework is critical to successfully implementing and executing construction safety cases in a proactive manner. This paper explores what comprises CCM and the key attributes contributing to successful implementation.

Sign in / Sign up

Export Citation Format

Share Document