Flexible Pipes Subjected to SCC CO2: Review and Means to Increase Reliability on Service Life Applied to Brazilian Pre-Salt Fields

2021 ◽  
Author(s):  
Mauricio Brandao ◽  
Fabio Pires ◽  
Ingrid Poloponsky ◽  
Fabio Santos ◽  
Diogo Lopes
Keyword(s):  
Fracture Mechanics ◽  
Service Life ◽  
Failure Mode ◽  
High Pressures ◽  
Small Scale ◽  
Materials Testing ◽  
Metallic Material ◽  
Remaining Service Life ◽  
Flexible Pipes ◽  
High Concentrations

Abstract Flexible Pipes were widely used in Brazil offshore developments and the challenge on overcoming increasing water depths, high pressures and fluids with high contaminants was always present. In 2017 a new failure mode, called SCC CO2 was disclosed bringing such disruption in the use of this equipment since, at that time, the conditions observed in Brazilian Pre salt were like the "perfect storm" for the failure mode to happen. It had high concentrations of CO2, therefore high permeation in the anulus, high stresses and the possibility to have anulus flooded as result of an outer sheath breach or even due to permeated water. These were the triple conditions needed to have the failure, considering that all metallic material used in the pipe were subjected to this phenomenon. Since the discovery was made, several test campaigns to better understand and replicate the phenomena started. They covered pipe retrieved from field dissection, several small-scale materials testing, and fracture mechanics to create reliable crack propagation calculations. There were 3 mains focus areas; to understand how to deal with the installed fleet, to define the conditions in which a crack would appear and define, using fracture mechanics, how long a crack would take to break the wire. In other words, it was intended to define what is the remaining service life. As a result of this investigation some initial beliefs like that all materials were subjected to the phenomena and that a solution was far away were somehow reduced and reshaped. There was also the initiative to embark on technology for detection of the anulus condition, mainly to define if it is flooded or not. Some ROV inspection means were added to the endfitting and some sensors were added to the interconnected pipe sections that allow conditioning monitoring or inspection from the floating unit, not using a ROV. This paper will cover the improvements done since the disclosure of the phenomena in 2017, reviewing what is known about it so far, what is still to be discovered and how the results achieved to date can contribute for a more reliable and longer service life for the flexible pipes to be applied in a rich CO2 environment.

Seal Tight Endfitting and Means to Identify Annulus Condition for Pre-Salt Flexibles in Brazil

2020 ◽  
Author(s):  
M. O. Brandão ◽  
F. Pires ◽  
C. Benirschke ◽  
E. Almeida ◽  
T. Iecker ◽  
...  
Keyword(s):  
Water Stress ◽  
Service Life ◽  
Failure Mode ◽  
Acceptance Test ◽  
Development Phase ◽  
Flexible Pipe ◽  
Pipe Section ◽  
Flexible Pipes ◽  
Integrity Management ◽  
High Concentrations

Abstract The development of Brazil Offshore fields using flexible pipes took the advantage of the possibility to move around lines, anticipate the production and postpone the decision of where exactly the development phase wells should be placed, making the drilling campaign easier, cheaper and faster. For the Pre-Salt fields, mainly in Santos Basin, it is observed high concentrations of H2S and CO2, two major impact contaminants for the metallic layers of the flexible pipe. A new failure mode by SCC is the most concerning one and have several approaches either focused on the installed fleet or focused in the next pipes to be delivered. SCC is a condition that induces cracks in the pipes metallic layers and need three elements to happen: water, stress and susceptible material. If one of these three elements is suppressed, the phenomena is not to happen. This paper will cover and present a design of a seal tight end fitting also with capabilities to be seal tested from the shop during the factory acceptance test and further means to identify if the flexible pipe section is flooded or dry visually, using ROV This information is key for the integrity management of the flexible pipes applied to pre salt fields to assure the most extent of the service life.

A Possible Basis for Nondestructive Characterization of Ropes of Nylon 6

1997 ◽  
Vol 503 ◽  
Author(s):  
H. Jiang ◽  
M. K. Davis ◽  
R. K. Eby ◽  
P. Arsenovic
Keyword(s):  
Tensile Strength ◽  
Service Life ◽  
Fiber Diameter ◽  
Structural Parameters ◽  
Crystal Form ◽  
Nylon 6 ◽  
Remaining Service Life ◽  
Nondestructive Characterization ◽  
Fractional Content

ABSTRACTPhysical properties and structural parameters have been measured for ropes of nylon 6 as a function of the number of use operations. The fractional content of the α crystal form, sound velocity, birefringence, tensile strength and length all increase systematically and significantly with increasing the number of use operations. The fractional content of the γ crystal form and fiber diameter decrease with use. These trends indicate that the measurement of such properties and structural parameters, especially the length, provide a possible basis for establishing a reliable, rapid, and convenient nondestructive characterization method to predict the remaining service life of nylon 6 ropes.

Adhesives in engineering

1997 ◽  
Vol 211 (5) ◽  
pp. 307-335 ◽  
Author(s):  
A J Kinloch
Keyword(s):  
Molecular Weight ◽  
Fracture Mechanics ◽  
Service Life ◽  
Adhesive Joint ◽  
Adhesive Joints ◽  
Liquid Form ◽  
Engineering Applications ◽  
Advantages And Disadvantages ◽  
Load Carrying ◽  
Made In

When considering methods for joining materials, there are many advantages that engineering adhesives can offer, compared to the more traditional methods of joining such as bolting, brazing, welding, mechanical fasteners, etc. The advantages and disadvantages of using engineering adhesives are discussed and it is shown that it is possible to identify three distinct stages in the formation of an adhesive joint. Firstly, the adhesive initially has to be in a ‘liquid’ form so that it can readily spread over and make intimate molecular contact with the substrates. Secondly, in order for the joint to bear the loads that will be applied to it during its service life, the ‘liquid’ adhesive must now harden. In the case of adhesives used in engineering applications, the adhesive is often initially in the form of a ‘liquid’ monomer which polymerizes to give a high molecular weight polymeric adhesive. Thirdly, it must be appreciated that the load-carrying ability of the joint, and how long it will actually last, are affected by: (a) the design of the joint, (b) the manner in which loads are applied to it and (c) the environment that the joint encounters during its service life. Thus, to understand the science involved and to succeed in further developing the technology, the skills and knowledge from many different disciplines are required. Indeed, the input from surface chemists, polymer chemists and physicists, materials engineers and mechanical engineers are needed. Hence, the science and technology of adhesion and adhesives is a truly multidisciplined subject. These different disciplines have been brought together by developing a fracture mechanics approach to the failure of adhesive joints. The advances that have been made in applying the concepts of fracture mechanics to adhesive joints have enabled a better understanding of the fundamental aspects of adhesion and the more rapid extension of adhesives technology into advanced engineering applications.

Remaining service life diagnostic technology of insulators for power distribution equipment

2009 ◽  
Vol 167 (2) ◽  
pp. 1-9
Author(s):  
Shinsuke Miki ◽  
Hiroshi Okazawa ◽  
Taketoshi Hasegawa ◽  
Sei Tsunoda ◽  
Hiroshi Inujima
Keyword(s):  
Service Life ◽  
Power Distribution ◽  
Remaining Service Life ◽  
Diagnostic Technology

scholarly journals Maintenance Modelling of Ceramic Claddings in Pitched Roofs Based on the Evaluation of Their In Situ Degradation Condition

2020 ◽  
Vol 5 (9) ◽  
pp. 77
Author(s):  
Cláudia Ferreira ◽  
Ana Silva ◽  
Jorge de Brito ◽  
Ilídio S. Dias ◽  
Inês Flores-Colen
Keyword(s):  
Service Life ◽  
Maintenance Strategies ◽  
Total Replacement ◽  
Remaining Service Life ◽  
In Situ Degradation ◽  
Maintenance Policies ◽  
And Performance ◽  
The Impact ◽  
Maintenance Model

Existing maintenance policies have several limitations, mainly due to the lack of knowledge regarding the durability and performance of buildings. Usually, the maintenance policies are insufficiently accurate, neglecting the risk of failure over time and the global costs associated with repairs. In this study, a condition-based maintenance model, based on Petri nets, is proposed to evaluate the impact of three maintenance strategies of ceramic claddings in pitched roofs (CCPR): MS1—only total replacement; MS2—composed of total replacement and minor intervention and MS3—composed of total replacement, minor intervention and cleaning operations. In this study, 146 CCPR were inspected in situ, with a total area of 43,991.6 m2. The remaining service life of the CCPR; the global costs over the claddings’ lifetime (considering inspection, maintenance, replacement and disposal costs); the claddings’ degradation condition and the number of replacements during the time horizon are used to evaluate the performance of the different maintenance strategies through a simplified multi-criteria analysis. The results show that the gains in performance, in terms of expected service life and durability, of the consideration of preventive maintenance actions (minor interventions or cleaning operations) outweigh the increase of the operation costs.

scholarly journals 3D SSY Estimate of EPFM Constraint Parameter under Biaxial Loading for Sensor Structure Design

Sensors ◽  
2019 ◽  
Vol 19 (3) ◽  
pp. 735
Author(s):  
Ping Ding ◽  
Xin Wang
Keyword(s):  
Fracture Mechanics ◽  
Biaxial Loading ◽  
Structure Design ◽  
Theoretical Research ◽  
Small Scale ◽  
Validation Process ◽  
Wide Range ◽  
Sensor Structure ◽  
Estimate Method ◽  
Parameter Approach

Conventional sensor structure design and related fracture mechanics analysis are based on the single J-integral parameter approach of elastic-plastic fracture mechanics (EPFM). Under low crack constraint cases, the EPFM one-parameter approach generally gives a stress overestimate, which results in a great cost waste of labor and sensor components. The J-A two-parameter approach overcomes this limitation. To enable the extensive application of the J-A approach on theoretical research and sensor engineering problem, under small scale yielding (SSY) conditions, the authors developed an estimate method to conveniently and quickly obtain the constraint (second) parameter A values directly from T-stress. Practical engineering application of sensor structure analysis and design focuses on three-dimensional (3D) structures with biaxial external loading, while the estimate method was developed based on two-dimensional (2D) plain strain condition with uniaxial loading. In the current work, the estimate method was successfully extended to a 3D structure with biaxial loading cases, which is appropriate for practical sensor design. The estimate method extension and validation process was implemented through a thin 3D single edge cracked plate (SECP) specimen. The process implementation was completed in two specified planes of 3D SECP along model thickness. A wide range of material and geometrical properties were applied for the extension and validation process, with material hardening exponent value 3, 5 and 10, and crack length ratio 0.1, 0.3 and 0.7.

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