Tethered Catenary Riser: A New Deepwater Concept

2013 ◽  
Author(s):  
Jean-Luc Legras ◽  
Baptiste Pillet
Keyword(s):  
Cost Effective ◽  
Field Development ◽  
Dynamic Excitation ◽  
Sea Bed ◽  
Engineering Work ◽  
Heavy Lift ◽  
Water Developments ◽  
Steel Catenary Risers ◽  
The One ◽  
Single Pipe

A new riser concept is proposed by Subsea 7 for field development in deep and ultradeep waters: the Tethered Catenary Riser (TCR)-patent pending. The concept consists of a number of steel catenary risers (SCRs) supported by a subsurface buoy which is tethered down to sea-bed by means of a single pipe tendon and anchored by means of a suction pile; flexible jumpers are used to make the connection between the Floating production Unit (FPU) and the buoy. Umbilicals run without interruption from the FPU to their subsea end while being supported by the buoy. The system has all the advantages of de-coupled riser arrangements: flexible jumpers effectively absorb platform motions, thereby the rigid risers and tendon have very small dynamic excitation. The system can be installed before FPU arrival on site, which improves the time before first oil. Analyses have shown that, with adequate geometry of the buoy, the latter is sufficient stable to induce acceptable tilt and twist when different arrangements of SCRs and flexible jumpers are installed, and under accidental scenarios during the in-place life. The riser system is best designed for a number of risers between 4 and 8, in addition to a number of umbilicals, thus convenient for one or two drilling centers. Results of the basic engineering work on the TCR clearly indicate that it is possible to have a robust design using presently qualified materials and technology. The components used in the TCR are all field proven as they are commonly used in existing riser systems. As a result of installation studies, a method very similar to the one commonly used by Subea7 for Single Hybrid Risers (SHRs) has been selected for the buoy and tether system. Placement of rigid risers, jumpers and umbilicals is as done by Subsea 7 for the Buoy Supporting Risers (BSRs). This method is well adapted for installation by the new Subsea 7 flagship vessel Seven Borealis which is able to perform heavy lift and pipe laying. The Tether Catenary Riser is a credible option for use in deep water developments all over the world. Since all the components, design methods and installation procedures are fully qualified and familiar to Subsea 7, the concept is cost effective and ready for project application.

Steel Lazy Wave Riser Configuration for Turret Moored FPSO With Disconnectable Turret in Deepwater

2015 ◽  
Author(s):  
Daniel Karunakaran ◽  
Sankar Subramanian ◽  
Rolf Baarholm
Keyword(s):  
Deep Water ◽  
Cost Effective ◽  
Attractive Alternative ◽  
Harsh Environment ◽  
Detailed Case ◽  
Effective Manner ◽  
Water Developments ◽  
Pros And Cons ◽  
Steel Catenary Risers

Recently turret-Moored FPSOs have been used in many deep water developments worldwide, with consideration of disconnectable turrets for harsh environment applications. This trend makes the interactions between FPSO and risers system more important. Further, Steel Lazy Wave Risers (SLWR), which is a compliant variant of the mostly commonly used Steel Catenary Risers (SCR), is becoming an attractive riser option. The paper provides a review of the various riser systems that can be considered for turret-moored FPSOs, and specific emphasis on Steel Lazy Wave Risers. A detailed case study of Steel Lazy Wave Risers for a typical turret moored FPSO with disconnectable turret is presented. This system is described in terms of design and functionalities, the fabrication and installation methods are presented. The case study shows clearly that SLWR are an attractive alternative to be used for FPSO with disconnectable turret and is very efficient to fabricate and install in a very cost effective manner. Pros and Cons for SLWR are discussed, with consideration of the particular challenges of turret-moored FPSOs with large floater motions, hang-off geometry constraints at turret, hang-off loads, riser interferences, risers pre-installation, and turret disconnection constraints.

Vessel Adapted for Multiple Installation and Salvage

2008 ◽  
Author(s):  
Jean-Marc Cholley ◽  
Nicolas Tcherniguin ◽  
Pierre Armand Thomas
Keyword(s):  
Wind Farm ◽  
Cost Effective ◽  
Air Gap ◽  
Offshore Wind ◽  
Offshore Wind Farm ◽  
Heavy Lift ◽  
Water Developments ◽  
Cost Effective Alternative ◽  
Weight Transfer ◽  
Turbine Installation

For offshore developments, the installation of production decks onto floaters (e.g. spars for deep water developments) or fixed platforms using a heavy lift derrick barge is now well established, though, for high payloads, this requires multiple lifts and hence extensive offshore hook-up. As demand for lift vessels increases, their availability to match a specific project’s schedule cannot be guaranteed. Consequently, an alternative deck installation vessel design has been developed for not only installing decks onto floaters, but also onto high air gap (circa 20 m) fixed platforms. This paper will present this new design. The new vessel design consists of a linked catamaran shaped vessel with dimensions that permit it to go around the floater hull or jacket so that the deck can be lowered and stabbed. The procedure for lowering is based on motorized “legs” to achieve a rapid weight transfer in severe sea-states and also permits the deck to be raised up once at site to achieve a high air gap installation on a fixed substructure. This new vessel design greatly extends the geographical range for deck installation using the float-over method and offers a cost effective alternative to relying on crane vessels for installation. Additionally, the vessel can perform a range of other tasks, particularly relating to decommissioning of facilities, or offshore wind-farm turbine installation.

Steel Lazy Wave Riser Design for Semi-Submersible in Harsh Environment

2014 ◽  
Author(s):  
Jingyun Cheng ◽  
Peimin Cao
Keyword(s):  
Water Depth ◽  
Optimal Solution ◽  
Cost Effective ◽  
Harsh Environment ◽  
Depth Range ◽  
Strength Performance ◽  
Field Development ◽  
Steel Catenary Risers ◽  
Riser Design ◽  
Design Guidance

Deep draft production semi-submersible with steel lazy wave risers (SLWRs) has been studied for the 2,625ft water depth in harsh environment. The design challenges and feasibility of steel catenary risers (SCRs) for semi-submersible at relatively shallow water and harsh environment are discussed. The benefits of using SLWRs to improve riser strength and fatigue performance are presented. Due to the complexity of SLWR geometry, a systematic configuration approach is introduced to achieve the desired riser performance target. A comparison study on fatigue and strength performance of various riser configurations is performed. The assessment provides design guidance for the optimal solution of the integrated hull, mooring and riser system. It concludes that deep draft production semi-submersible with SLWRs can be a feasible and cost effective solution for field development at water depth range from 2,297ft to 3,281ft in harsh environment.

scholarly journals Sprouting of Sorghum (Sorghum bicolor [L.] Moench): Effect of Drying Treatment on Protein and Starch Features

Foods ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 407 ◽  
Author(s):  
Mia Marchini ◽  
Alessandra Marti ◽  
Claudia Folli ◽  
Barbara Prandi ◽  
Tommaso Ganino ◽  
...  
Keyword(s):  
Food Production ◽  
Cost Effective ◽  
High Exposure ◽  
Effective Technology ◽  
Drying Treatment ◽  
Higher Temperature ◽  
Lower Temperature ◽  
The One ◽  
Drying Conditions ◽  
Sorghum Bicolor L

The nutritional and physicochemical properties of sorghum proteins and starch make the use of this cereal for food production challenging. Sprouting is a cost-effective technology to improve the nutritional and functional profile of grains. Two drying treatments were used after sorghum sprouting to investigate whether the drying phase could improve the protein and starch functionalities. Results showed that the drying treatment at lower temperature/longer time (40 °C for 12 h) extended the enzymatic activity that started during sprouting compared to the one performed at higher temperature/shorter time (50 °C for 6 h). An increased protein hydrolysis and water- and oil-holding capacity were found in the flour obtained by the former treatment. Higher protein matrix hydrolysis caused high exposure of starch to enzymes, thus increasing its digestibility, while worsening the technological functionality. Overall, modulating drying conditions could represent a further way, in addition to sprouting, to improve sorghum flour’s nutritional profile.

Development of efficiency increase methods for water injection

2020 ◽  
pp. 57-60
Author(s):  
K.I. Mustafaev ◽  
◽  
◽  
Keyword(s):  
Water Injection ◽  
Cost Effective ◽  
Current Interest ◽  
Residual Oil ◽  
Production Well ◽  
Field Development ◽  
Oil Reserves ◽  
Production Wells ◽  
Efficiency Increase

The production of residual oil reserves in the fields being in a long-term exploitation is of current interest. The extraction of residual oil in such fields was cost-effective and simple technological process and is always hot topic for researchers. Oil wells become flooded in the course of time. The appearance of water shows in production wells in the field development and operation is basically negative occurrence and requires severe control. Namely for this reason, the studies were oriented, foremost, to the prevention of water shows in production well and the elimination of its complications as well. The paper discusses the ways of reflux efficiency increase during long-term exploitation and at the final stages of development to prevent the irrigation and water use in production wells.

scholarly journals Simple and Visible Detection of Novel Astroviruses Causing Fatal Gout in Goslings Using One-Step Reverse Transcription Polymerase Spiral Reaction Method

2020 ◽  
Vol 7 ◽  
Author(s):  
Jun Ji ◽  
Qinxi Chen ◽  
Zhengli Yu ◽  
Xin Xu ◽  
Xinhao Mu ◽  
...  
Keyword(s):  
Reverse Transcription ◽  
Cost Effective ◽  
Pcr Primers ◽  
Probit Regression ◽  
Conventional Pcr ◽  
Specific Detection ◽  
Isothermal Method ◽  
Naked Eye ◽  
One Step ◽  
The One

In this study, a one-step isothermal method combining polymerase spiral reaction (PSR) with reverse transcription (RT-PSR) was established for rapid and specific detection of novel astroviruses causing fatal gout in goslings (N-GoAstV). The one-step RT-PSR was accomplished at the optimal temperature of 62°C and time of 40 min and used primers simply designed as conventional PCR primers, and the results of detection were visible to the naked eye. The detection limit of PSR was above 34.7 copies/μL at a 95% probability level according to probit regression analysis. The assay specifically detected N-GoAstV, and no other reference viruses were detected. These results suggest that the newly established RT-PSR assay could, in one step, accomplish reverse-transcription, amplification, and result determination providing a visible, convenient, rapid, and cost-effective test that can be carried out onsite, in order to ensure timely quarantine of N-GoAstV-infected birds, leading to effective disease control.

A computer simulation model of forest fire suppression with air tankers

1979 ◽  
Vol 9 (3) ◽  
pp. 390-398 ◽  
Author(s):  
A. J. Simard
Keyword(s):  
Computer Simulation ◽  
Simulation Model ◽  
Historical Data ◽  
Fire Suppression ◽  
Cost Effective ◽  
Computer Simulation Model ◽  
Fire Dynamics ◽  
Data Output ◽  
The One ◽  
Fire Ground

A computer simulation model which evaluates air tanker productivity and effectiveness is described. Three hundred equations are required to define the model, which consists of five components: administration, the environment, the fire, ground suppression, and air tanker utilization. AIRPRO, a computer program based on the model, tests various combinations of air tanker resources and tactics and selects the one which minimizes suppression cost plus damage caused by fire. The program contains four loops: the fire, the tactic, the event, and fire dynamics (growth and suppression). The environmental, fire, and ground suppression components were validated by comparing model output with historical data. Output of the air tanker component was examined for reasonableness, compared with previous research, and a sensitivity analysis was performed. It is concluded that an assumption of model validity is reasonable. In applying the model in New Brunswick, it was found that medium sized land-based air tankers were the most cost effective, followed by small land-based air tankers. It was also found that a fleet of three or four aircraft would be optimum.

Better regulation, administrative sanctions and constitutional values

Legal Studies ◽  
2013 ◽  
Vol 33 (2) ◽  
pp. 312-339
Author(s):  
Karen Yeung
Keyword(s):  
Due Process ◽  
Cost Effective ◽  
The Other ◽  
Regulatory Enforcement ◽  
The Rule Of Law ◽  
Enforcement Action ◽  
Better Regulation ◽  
The One ◽  
The Uk ◽  
Administrative Sanctions

This paper interrogates the predisposition in favour of informal, low-intervention control styles of enforcement advocated by the ‘better regulation’ movement, and which resonates throughout the Hampton Report recommendations which are currently being implemented in the UK. It focuses on three practices that reflect the trend towards diverting regulatory enforcement action away from the courts in favour of reliance on formal administrative sanctioning powers ranging from ‘hard’ to ‘soft’: the use of negotiated penalty settlements, the acceptance of administrative undertakings (‘enforcement undertakings’) and the provision of firm-specific compliance advice by regulators. Each practice is explored through various analytical lenses which enable the underlying constitutional tensions to be identified and interrogated. In so doing, it demonstrates how the emphasis on bargaining, negotiation and discussions between regulators and those they are responsible for regulating advocated by the UK better regulation movement may antagonise several constitutional values, including transparency, accountability, due process and participation, as well as several values associated with formal conceptions of the rule of law. On the other hand, resort to negotiation and discussion in regulatory enforcement can generate important benefits, largely in facilitating the timely, creative and cost-effective resolution of enforcement disputes while avoiding the formality, delay and hostility associated with formal court adjudication. This ‘clash of logics’ can be traced to inherent differences between bargaining, on the one hand, and adjudication on the other. Bargaining and adjudication represent two quite different and distinct forms of ordering through which disputes can be resolved, and it is these differences that lie at the foundation of their respective virtues and shortcomings when employed to resolve disputes concerning regulatory violations.

Sensitivity Study of Critical Parameters Influencing the Uncertainty of Fatigue Damage in Steel Catenary Risers

2010 ◽  
Author(s):  
Feng Zi Li ◽  
Ying Min Low
Keyword(s):  
Fatigue Damage ◽  
Cost Effective ◽  
Sensitivity Study ◽  
Structural Safety ◽  
Critical Parameters ◽  
Design Parameters ◽  
Steel Catenary Riser ◽  
Bending Stresses ◽  
Steel Catenary Risers ◽  
Touchdown Point

The most challenging aspect of a deepwater development is the riser system, and a cost-effective choice is the Steel Catenary Riser (SCR). Fatigue is often a governing design consideration, and it is usually most critical at the touchdown point (TDP) where static and dynamic bending stresses are highest. Unfortunately, it is also at this region that uncertainty is the maximum. The increased uncertainty casts doubt on the applicability of generic safety factors recommended by design codes, and the most consistent way of ensuring the structural safety of the SCR is to employ a reliability-based approach, which has so far not received attention in SCR design. As the number of basic random variables affects the complexity of a reliability analysis, these variables should be selected with caution. To this end, the aim of this paper is to draw up a comprehensive list of design parameters that may contribute meaningfully to the uncertainty of the fatigue damage. From this list, several parameters are selected for sensitivity studies using the commercial package Orcaflex. It is found that variations in seabed parameters such as soil stiffness, soil suction and seabed trench can have a pronounced influence on the uncertainty of the fatigue damage at the touchdown point.

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