Increased safety and improved operation of pipelines with integrated condition sensing in flexible risers and flowlines

2014 ◽  
Vol 54 (1) ◽  
pp. 295 ◽  
Author(s):  
Bo A. Andersen
Keyword(s):  
Condition Monitoring ◽  
Failure Modes ◽  
Optimum Level ◽  
Steel Pipes ◽  
Offshore Production ◽  
Flexible Pipes ◽  
Accurate Picture ◽  
Maximum Period ◽  
Integrity Management ◽  
Flexible Risers

Continuous condition monitoring of offshore production installations is a vital part of integrity management to ensure safe operation of the asset at its optimum level for the maximum period of time. The recent implementation of fiber-optic condition monitoring embedded into the structures of flexible risers and flowlines is an important step towards turning flexible pipelines into inspectable structures. Embedded sensors enable a suite of monitoring options for both real-time response and long-term changes, which can provide a highly accurate picture of a pipeline’s condition during operation. In this paper the author reports the results from extensive full-scale testing on flexible pipes instrumented with sensors, conducted in cooperation with a major operator. The testing includes detection of a breach of the outer sheath with ingress of seawater into the annulus, remote monitoring of the location of accessories mounted on the pipe—such as buoyancy modules—monitoring of the temperature at a buried section of a pipe in the seabed, identification of hotspots, detection of breaks of tensile armor wires, and monitoring of accumulated fatigue damage in tensile armor wires during operation. Reported failure modes from flexible pipes in operation are briefly discussed to show that the major failure modes reported across all operators through the years are covered by the NOV integrated sensing systems. The detection of structural and temperature issues with integrated condition sensing in flexible pipelines will allow operators to satisfy requirements for periodic inspection, which for rigid steel pipes is performed with intelligent pigging.

Flexible Risers Lifetime Extension: Riser In-Service Monitoring and Advanced Analysis Techniques

2017 ◽  
Author(s):  
Hany Elosta ◽  
Thierry Gavouyere ◽  
Pierrick Garnier
Keyword(s):  
Service Life ◽  
Dynamic Behaviour ◽  
Primary Objective ◽  
Original Design ◽  
Analysis Techniques ◽  
Flexible Pipes ◽  
Integrity Management ◽  
Advanced Analysis ◽  
Flexible Risers ◽  
Lifetime Extension

The demand for the lifetime extension of flexible pipes is increasing due to the need to extend the lifetime of the existing production fields. There have been many challenges with the lifetime extension of flexible pipes after the end of the initial design service life due to the inherent conservatism with the common analysis approach, safety factors and operation beyond the design limits. A lifetime assessment should be performed on flexible risers for re-qualification during the original design life if the design envelope is exceeded or there is a need for lifetime extension. Hence, a systematic approach for lifetime assessment execution is established to determine the integrity level of the flexible risers and define the recommended actions required, such as mitigations, repairs or monitoring to maintain an acceptable risk for the required extended service life based on consistent methodology. The primary objective of this paper is to present a riser integrity management field-proven technology to monitor the riser’s behaviour in-service in addition to the advanced analyses guidelines to form a basis for the lifetime extension of flexible risers. The primary objective for the integrity management is to manage and control the risk of failure by detecting failure at an earlier stage when preventive action can be taken to avoid failure propagation. In addition, it is demonstrated that the primary hot-spots for the dynamic behaviour and fatigue life assessments of the flexible risers are primarily in bend stiffener regions and the touchdown zone (TDZ) due to large tension fluctuations caused by vessel motions and cyclic movement in the TDZ. Therefore, analysis techniques have been developed in two primary areas: advanced bend stiffener modelling using pipe-in-pipe (PIP) to model the sliding friction and the bend stiffener/flexible pipe’s annular space and flexible pipe–seabed interaction modelling using a non-linear seabed model. Therefore, the flexible riser’s lifetime extension assessment will be based on more reliable models that reflect the realistic and dynamic behaviour of the flexible risers. Consequently, these advanced analysis techniques can be used for new designs or lifetime extension of flexible pipes.

Properties of Unbonded Flexible Pipe under Axial Force

2014 ◽  
Vol 651-653 ◽  
pp. 1004-1008
Author(s):  
Wei Wang ◽  
Lei Sun ◽  
Yang Liu
Keyword(s):  
Axial Force ◽  
Fe Model ◽  
Flexible Pipe ◽  
Fe Method ◽  
Shell Elements ◽  
Steel Pipes ◽  
Offshore Production ◽  
Flexible Pipes ◽  
The Given ◽  
Good Agreement

Flexible pipes, which can be divided into bonded and unbonded types, have been used for years in the oil industry. An unbonded structure presents a large interest in offshore production as they allow to realize simple liaison between the seafloor and the surface. In the present paper, an unbonded flexible pipe under axial force has been analyzed by finite element (FE) method in which eight layers of the unbonded flexible pipe have established. Solid and shell elements are used to simulate the layers. In the FE model, all layers are modeled separately with contact and friction interfaces between each layer. The numerical results are compared to the literature’s results, which shows very good agreement with numerical and other existing results, have validated the use of the given model. It might provide practical and technical support for the application of flexible steel pipes.

Carcass Failures in Multilayer PVDF Risers

2013 ◽  
Author(s):  
Knut-Aril Farnes ◽  
Claus Kristensen ◽  
Steinar Kristoffersen ◽  
Jan Muren ◽  
Nils Sødahl
Keyword(s):  
Failure Modes ◽  
Load Model ◽  
Flexible Pipes ◽  
Flexible Risers

Statoil have experienced failures in a number of flexible risers due to collapse, overload, tearing and unspiraling of the carcass in pipe structures with multi-layer PVDF pressure barrier. The paper will discuss the carcass failure modes that are characteristic for multilayer flexible pipes with particular focus on the failures due to carcass tearing. The nature of the carcass tearing problem is explained and suggestions for load model and operational policy for mitigation risk of new failures is presented.

SPIRE: Flexible Riser Condition Monitoring System Applied to Pre-Salt Fields With High CO2

2020 ◽  
Author(s):  
M. O. Brandão ◽  
J. Lima ◽  
E. Almeida ◽  
O. Borges ◽  
J. McCarthy ◽  
...  
Keyword(s):  
Failure Modes ◽  
High Pressures ◽  
Mitigation Measures ◽  
Next Generation ◽  
Oil Composition ◽  
Embedded Sensing ◽  
Flexible Pipes ◽  
The Status ◽  
Integrity Management ◽  
Condition Monitoring System

Abstract The development of Brazil’s Offshore fields has been performed using flexible pipes because this pipe technology offers significantly increased flexibility, enabling the movement of pipes between wells and reducing lead time to bring a well onstream as compared to rigid pipe solutions. In addition, the decision of where exactly to drill development wells can be delayed, thus making the drilling campaigns easier, cheaper and faster [1]. With the increased activity in Pre-Salt, some challenges to flexible pipes were uncovered and needed to be addressed, notably oil composition and corrosive agents, e.g. H2S, and, specifically for the case of this paper, CO2. At high pressures, such as found in pre-Salt fields, these contaminants create new Stress Corrosion Cracking (SCC) failure modes and several mitigation measures have been adopted to overcome them, focused either on the installed fleet or on the next generation of pipes to be delivered. SCC is a condition that induces failure in the pipes’ metallic layers, but it needs three elements to occur: water, tensile stress exceeding a critical level and a susceptible material. If one of these three elements is suppressed, the phenomena does not to happen. This paper will cover and present a technology developed to detect the annulus water condition — dry or flooded — and thereby allow a correct integrity management strategy to be adopted. The technology is based on an embedded sensing system together with topside equipment to read the status. The use of such a system is important for the next generation of flexible pipes as it will allow better management of the fleet, with the required measurements performed from the production unit without the need of any support vessel and hence at a reduced cost.

New Advances in Flexible Riser Monitoring Techniques Using Optical Fiber Sensors

2012 ◽  
Author(s):  
Sérgio R. K. Morikawa ◽  
Arthur M. B. Braga ◽  
Claudio S. Camerini ◽  
Carla C. Kato ◽  
Roberth A. Llerena ◽  
...  
Keyword(s):  
Structural Damage ◽  
Laboratory Tests ◽  
Failure Modes ◽  
Fiber Optic ◽  
Gas Production ◽  
Strain Sensors ◽  
Brazilian Coast ◽  
Outer Sheath ◽  
Flexible Pipes ◽  
Flexible Risers

Petrobras oil and gas production in the deep and ultra deepwater fields in Campos Basin and other provinces off the Brazilian coast heavily relies on flexible pipes. Maximizing the availability and reliability of an extensive offshore pipeline network poses innumerous challenges to the Company, which is steadily moving towards a condition based approach to maintenance of their flexible risers. In this context, Petrobras, in cooperation with its academic partners, has launched a comprehensive R&D program named MONFLEX, focusing on novel techniques for structural monitoring of flexible risers. Years of field experience have demonstrated that one of the most frequent failure modes of flexible pipes is the sequential rupture of wires in their tensile armor layers [1]. The MONFLEX Program has explored a range of different technologies in order to timely detect and monitor the growth of this class of progressive structural damage. Some of the proposed approaches have relied on video cameras pointed towards fixedly mounted targets on the riser outer sheath, vibration and acoustic methods, these in a wide frequency range, and techniques based on fiber optic strain sensors. All three have been experimentally deployed in the field and are currently being evaluated. Among those, fiber optic monitoring is the one that has shown the better promise of becoming the chosen method for detecting wire ruptures in the riser’s armor layers. The fiber optic based monitoring system developed in the MONFLEX R&D Program has been named MODA, which, in Portuguese, stands for Direct Wire Optical Monitoring. The MODA system consists in instrumenting all the wires of the riser’s external tensile armor layer with fiber Bragg grating strain sensors. In flexible risers already in operation, a window in the polymeric outer sheath of the pipe is temporarily opened in order to allow the sensors installation, and then repaired with a protective, anticorrosive layer. Even though in MODA the strain sensors are installed in the external armor layer, full scale laboratory tests have demonstrated that the algorithm employed to treat and analyze the real time data provided by the system is capable of instantaneously detecting ruptures of wires either in the external or internal layers of the tensile armor. The proposed contribution will report the later results of extensive laboratory tests and field trials performed with the MODA system.

Operators Experience With Flexible Risers

2002 ◽  
Author(s):  
Gudmund Per Olsen ◽  
Ketil Rongved
Keyword(s):  
Failure Modes ◽  
Lifetime Prediction ◽  
Norsk Hydro ◽  
The Future ◽  
Flexible Risers

Norsk Hydro has more than 150 flexible dynamic risers and service lines in operation. Norsk Hydro’s experience with flexible risers started in 1987 when Petrojarl 1 commenced test production at the Oseberg Field. The paper tells the story about Norsk Hydro’s experience through the 15 years of trials with a new and complicated product. This paper will focus on “what went wrong”. This may seem unfair to the product! However, without flexibles we would probably not have seen such successful field developments as the Troll B and C, Njord, Visund and Snorre B. Challenging production and installation schemes have been put forward and fulfilled. However, hopefully this paper can give an insight in failure modes, and so forth give input to enhanced solutions in order to avoid similar situations in the future. This paper gives an overview over the different approaches which have been taken to give a better qualification of the lifetime prediction of the risers. Some of the specific projects will be presented in detail in other papers on this conference.

The Role of Offshore Monitoring in an Effective Deepwater Riser Integrity Management Program

2007 ◽  
Author(s):  
Brittany Goldsmith ◽  
Elizabeth Foyt ◽  
Madhu Hariharan
Keyword(s):  
Failure Modes ◽  
Human Life ◽  
Management Program ◽  
Measured Data ◽  
Operating Conditions ◽  
Environmental Damage ◽  
Positioning Systems ◽  
Integrity Management ◽  
Deepwater Riser

As offshore field developments move into deeper water, one of the greatest challenges is in designing riser systems capable of overcoming the added risks of more severe environments, complicated well requirements and uncertainty of operating conditions. The failure of a primary riser component could lead to unacceptable consequences, including environmental damage, lost production and possible injury or loss of human life. Identification of the risks facing riser systems and management of these risks are essential to ensure that riser systems operate without failure. Operators have recognized the importance of installing instrumentation such as global positioning systems (GPS), vessel motion measurement packages, wind and wave sensors and Acoustic Doppler Current Profiler (ADCP) units to monitor vessel motions and environmental conditions. Additionally, high precision monitoring equipment has been developed for capturing riser response. Measured data from these instruments allow an operator to determine when the limits of acceptable response, predicted by analysis or determined by physical limitations of the riser components, have been exceeded. Regular processing of measured data through automated routines ensures that integrity can be quickly assessed. This is particularly important following extreme events, such as a hurricane or loop current. High and medium alert levels are set for each parameter, based on design analysis and operating data. Measured data is compared with these alert levels, and when an alert level is reached, further response evaluation or inspection of the components in question is recommended. This paper will describe the role of offshore monitoring in an integrity management program and discuss the development of alert levels based on potential failure modes of the riser systems. The paper will further demonstrate how this process is key for an effective integrity management program for deepwater riser systems.

Torsion Failures in Handling Operations for Power Cables, Umbilicals and Flexible Pipes

2021 ◽  
Author(s):  
Philippe Mainçon ◽  
Vegard Longva
Keyword(s):  
Failure Modes ◽  
Compressive Load ◽  
Qualitative Description ◽  
Power Cables ◽  
Knowledge Gaps ◽  
The Past ◽  
Flexible Pipes ◽  
Systematic Nomenclature ◽  
Component Failures ◽  
Flexible Products

Abstract Over the past 10 years, SINTEF has investigated, or been informed about, a range of torsion failures in cables, umbilicals or flexible pipes. These failures have occurred while the flexible products were being transported along a route during production, loadout, installation. One failure occured during operation. There are no guidelines on how to minimize the risk of such failures. This may be attributed to a lack of knowledge in the industry about the mechanisms that cause torsional moments to appear. Further, some buckling patterns of the components of a flexible product under excessive torsion, closely resemble patterns caused by excessive bending or compressive load, so that some torsion-induced failures are wrongly attributed. Hence, there is a need to increase the knowledge and awareness of torsion failures in the industry. Previous papers by the authors have considered some of the mechanisms that lead to the appearance of torque in handling operations. The present paper is a continuation which focuses on torque-induced failure modes. It begins by providing a systematic nomenclature for the description of torsion kinematics. It then provides a qualitative description of known torque-induced failure modes. The literature provides some models for torque-induced failures, as well as models of component failures due to excessive bending or compression of the flexible product, which are also relevant for the study of torsion. These are reviewed, and their relevance to torsion-induced failures are discussed. Knowledge gaps and challenges are highlighted.

Non-Metallic Technology Deployment for the Next Generation of ADNOC Production Facilities

2021 ◽  
Author(s):  
Raymond Nicholas Burke ◽  
Abdallah Mohd AR Al Tamimi ◽  
Wael Salem Al Shouly ◽  
Mohamed Ali Jaber ◽  
David Erik Baetsen
Keyword(s):  
Group Technology ◽  
Steering Committee ◽  
Thermoplastic Composite ◽  
Gas Field ◽  
Steel Pipes ◽  
Pilot Trials ◽  
Integrity Management ◽  
One Year ◽  
Corrosion Of Steel ◽  
Duration Of Operation

Abstract Industry-wide, the degradation and corrosion of steel infrastructure and the associated maintenance to prevent or mitigate this, poses a heavy environmental and operational burden across many industry segments. To address these challenges, ADNOC Group Technology, led by our Non-Metallic Steering Committee and ADNOC Upstream, in partnership with several selected specialist product companies, is deploying a range of innovative solutions as pilot trials within a holistic R&D program – which is aiming to transform our production and processing facilities, with a close focus on integrity management – and specifically we are assessing the deployment of non-metallic pipelines, storage and process vessels as well as downhole tubing and casing. Focusing specifically on flowlines and pipelines - traditional steel pipes used in the oil patch are burdensome to store, transport and install, as well as susceptible to degradation, corrosion-driven wall loss in challenging operational environments, such as those found Onshore and Offshore Abu Dhabi. This vulnerability results in increased operating risks as facilities mature, adding cost and time for inspection, maintenance and eventually - replacements that will lead to production deferrals or interruptions. A range of non-metallic pipeline technologies are being assessed and piloted in this program, including stand-alone extruded polymeric pipe and liners, Reinforced Thermoplastic Pipe (RTP) used Onshore and Offshore, specialized non-metallic flexible pipelines for Offshore including Thermoplastic Composite Pipe (TCP) and downhole tubulars. The methodology involves placing segments of RTP into live pipeline systems for a finite duration of operation – usually one year – and then removing sections to assess any degradation in performance, or capability of the RTP during that time. These test results will be the subject of a further publication at the end of this trial period. In this paper, we will focus on RTP piloting Onshore and specifically mention a unique trial in an ultra-sour gas field, where the technology has already delivered the required performance: safely transporting gas with levels of H2S up to 10% by volume. This trial also proves that specifically engineered non-metallic products may be successfully operated at the high temperature and high pressure (HPHT) levels that are characteristic of our reservoirs.

Cathodic Protection Design Consideration for an Offshore Flexible Riser Connected to an Impressed Current System

2021 ◽  
Author(s):  
Thierry Dequin ◽  
Clark Weldon ◽  
Matthew Hense
Keyword(s):  
Cathodic Protection ◽  
Sacrificial Anode ◽  
Flexible Riser ◽  
Flexible Pipe ◽  
Linear Resistance ◽  
Flexible Pipes ◽  
Flexible Risers ◽  
Impressed Current ◽  
Host Structure ◽  
Impressed Current Cathodic Protection

Abstract Flexible risers are regularly used to produce oil and gas in subsea production systems and by nature interconnect the subsea production system to the floating or fixed host facilities. Unbonded flexible pipes are made of a combination of metallic and non-metallic layers, each layer being individually terminated at each extremity by complex end fittings. Mostly submerged in seawater, the metallic parts require careful material selection and cathodic protection (CP) to survive the expected service life. Design engineers must determine whether the flexible pipe risers should be electrically connected to the host in order to receive cathodic protection current or be electrically isolated. If the host structure is equipped with a sacrificial anode system, then electrical continuity between the riser and the host structure is generally preferred. The exception is often when the riser and host structure are operated by separate organizations, in which case electrical isolation may be preferred simply to provide delineation of ownership between the two CP systems. The paper discusses these interface issues between hull and subsea where the hull is equipped with an impressed current cathodic protection (ICCP) system, and provides guidance for addressing them during flexible pipe CP design, operation, and monitoring. Specifically, CP design philosophies for flexible risers will be addressed with respect to manufacturing, installation and interface with the host structure’s Impressed Current Cathodic Protection (ICCP) system. The discussion will emphasize the importance of early coordination between the host structure ICCP system designers and the subsea SACP system designers, and will include recommendations for CP system computer modeling, CP system design operation and CP system monitoring. One of the challenges is to understand what to consider for the exposed surfaces in the flexible pipes and its multiple layers, and also the evaluation of the linear resistance of each riser segment. The linear resistance of the riser is a major determinant with respect to potential attenuation, which in turn largely determines the extent of current drain between the subsea sacrificial anode system and the hull ICCP system. To model the flexible riser CP system behavior for self-protection, linear resistance may be maximized, however the use of a realistic linear resistance is recommended for evaluation of the interaction between the host structure and subsea system. Realistic flexible linear resistance would also reduce conservatism in the CP design, potentially save time during the offshore campaign by reducing anode quantities, and also providing correct evaluation of drain current and stray currents.

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