bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Flow Assurance Criticalities and Challenges Management of Zohr Deepwater Giant Gas Field
Authors: ElSayed Mohamed Salah , Zayed Samir , Tolba Mohamed Ahmed , Omar Muhammad Karam , Hussein Ola Amr , Darwish Hatem Mohamed , Negm Mohamed Nagy 
Published: April 2020

Abstract
Offshore oil and gas fields have gained tremendous importance for the world's energy supply. Our ability to tap into these reserves is one of the main reasons that the predictions of the "Club of Rome" in 1972 about diminishing hydrocarbon reserves and "limits to growth" turned out to be pessimistic.
As the transport of oil and gas products in a multiphase manner is increasingly stretched over greater distances with development in more hostile environments, especially when designing large-scale ultra-deepwater production network, it is mandatory to ensure sustaining reliable and robustness operations as the access to subsea infrastructure becomes increasingly limited and to reduce the influence on the downstream facilities.
An integrated multiphase dynamic model was used to optimize operating procedures for initial well clean-up and ramp-up to production from a sizeable deepwater production system before first gas. This approach was essential to create and test start-up scenarios given several well and reservoir uncertainties.
On the other hand, the transient analysis was performed to optimize the system's time-dependent operations, e.g., 215 KM pipelines start-up and shutdown; production Ramp-up; maximum no-touch time without hydrates; Depressurization of the network to remove hydrates and ensure flaring system adequacy; Optimized well routing; and Hydrodynamic slugging. All the simulations accounted for the uncertainty of the associated controlling parameters.
In this paper, we will present how we developed the integrated model. We will show how we used the simulation as a guidance tool to develop appropriate procedures for different transient operations. The framework presented here applies to any similar deepwater field with extra-long tie-back. This model is a handy tool not only for engineering simulation but for operator training and real-time surveillance as well.
How Machine Learning is Improving Production on Offshore Platforms
Authors: Herve Philippe , Prado Gabriel , Rosner Marla 
Published: April 2020

AbstractThe oil and gas industry is known for its volatile boom and bust cycles, and this has a particularly strong effect on offshore platforms, which are substantial investments that do not always succeed in generating profit. To generate value and remain competitive in the offshore sector, operators must ensure that their operations are efficient, optimized, unlikely to be interrupted by unexpected failures, and resilient to fluctuations in oil prices. Artificial intelligence, and more specifically, machine learning, applications allow operators to do all of this. This paper presents two specific case studies demonstrating how machine learning has been proven and scaled in a deployed environment, with tangible increase in offshore production leading to significant business value to the operator.
A Secondary Guide for Fracture Density Incorporating Structural Deformation, Distance from Faults and Fault Displacement
Authors: Valencia Israel 
Published: April 2020

AbstractThe objective of this paper is to show a methodology that generates a secondary guide for propagating fracture densities as input to a DFN (Discrete Fracture Network). Our goal is to provide a new idea for geomodelers who deal with complex fractured fields, and do not have enough information to build robust models for exploration and simulation.The secondary guide was developed to help geomodelers populate fracture properties on a reservoir model. The seismic data was of low quality, making it difficult to obtain good seismic attributes. Therefore, a guide was created that incorporated on the same attribute, information about the geocellular grid deformation, the distance from the fault planes, and the fault's displacement. All of the information used to generate the secondary guide was created from the structural model (interpolated surfaces -faults and horizons - perfectly sealed) and geocellular grid.It is also important to know that, depending on the type of deformation defined for the model, deformation results can vary. Once the three properties were calculated and placed in the same domain (the geological grid), they were rescaled. After that, they were merged in a new property according to the geomodeler's criteria.The quality of the results relied on the seismic interpretation of faults and horizons, so in order to generate a good guide, it was important to obtain the most accurate representation of the structural model. The values of the new output property varied as a function of the distance from the faults, but also as a function of the fault displacements, and the presence of the deformed rock. This allowed its correlation with the fracture density through use of a statistical function. The secondary guide did not include other fracture controllers, such as the probability of fractures, which was also controlled by the geomechanical parameters. That would be another property to be weighted in the process.The process was designed and applied to a real case. The methodology enabled the geomodeler to distribute fracture densities and their properties without the use of seismic attributes. The workflow is applicable to any kind of fractured reservoir and can be used anywhere, from exploration to production.
Qualification of Corrosion Resistant Steel Catenary Risers using Polymer Lining Technology
Authors: McCord Craig , Jones Colin 
Published: April 2020

Abstract
Corrosion protection of water injection Steel Catenary Risers (SCRs) has been identified as a multi discipline challenge facing the industry. Readily available solutions often lead to excessive riser weight and top tensions, expensive materials, complex welding solutions, and increased fabrication time and risk. Currently, a technology qualification program for an integrated liner system in dynamic riser service is aiming to address this and achieve formal Technology Readiness Level 5 (TRL5 from DNVGL-RP-A203) by Q3 2020.
Individual components of a liner system are often unique and proprietary requiring individual qualification. This multi discipline program utilizes an integrated liner system incorporating carbon steel host pipe (including girth welds), polymer liner (including butt fusion welds), electrofusion welded polymer connectors (EWPC), and mechanical corrosion resistant alloy terminations (MCRAT). Fatigue testing is the primary method of assessment in this case, a series of nine fatigue trials spread over three stress ranges; 200MPa, 150MPa and 100MPa, have been scoped.
Initial positive results have proven the concept of using the integrated liner system components in the dynamic riser application with successful completion of high stress range (200MPa) fatigue tests utilizing the full integrated liner system. To date, the conducted fatigue testing achieves performance equivalent to DNVGL-RP-C203 S-N curve D (in water with cathodic protection) after subjecting the pipe to pre-straining via reeling trials. Upon scope completion, it is expected to extend performance to meet the requirement for S-N curve C/2. Completion of testing with an intact corrosion barrier combined with assessment of vertical orientation on the system enables design of polymer lined pipelines suitable for dynamic riser service.
The integrated liner system offers a potential step change in SCR and SLWR design. The technology application is able to provide key benefits such as an optimized design over the life of the pipeline, improved flow assurance, minimized installation complexity, optimized host and operational needs, thus resulting in an efficient and optimized field life cycle.
Mobile Mudmats for Subsea Field Development Structures
Authors: Bughi Sabrina , Marchionni Lorenzo 
Published: April 2020

Abstract
Mobile mudmats are increasingly adopted as foundation solution for subsea structures in offshore field developments, to allow their horizontal movement under the cyclically imposed expansion/contraction operating loads from the connected lines. The foundation compliance grants the dissipation of the applied loads while the structure slides on the seabed and the required base dimensions are reduced. Foldable solutions can even be installed integrated with the related lines, passing through the pipelay vessel tower.
The described experience is based upon design and installation of mobile mudmats for subsea structures in the last twenty years of activity in several deepwater areas all over the world. The design has been improved with time and its robustness has been demonstrated using alternative analytical approaches and Finite Element Model of the system with proper definition of soil-foundation behavior through equivalent springs. The geotechnical engineering effort focused to ensure the foundation adequate bearing capacity and its ability to slide under repeated thermal/pressure expansion loads during design lifetime, without developing excessive settlements and pitch/roll unacceptable rotations that could compromise the system performance.
The purpose of the present work is to raise awareness of the need for reference international criteria for the design of mobile foundations, which represent an important solution for a subsea field development. Available Codes and Standards do not cover the relevant aspects of the mobile foundation engineering: they are based upon fixed foundation concept, which is expected to be stable under all the applied load combinations without developing any significant displacement. The mobile foundation engineering challenge is to accept that a failure mechanism develops in sliding condition while proper design criteria of system stability and reliability are fulfilled.
Valuable and impressive research works have been carried out and published on the subject in the recent years. However, for practical application, specific criteria are required to provide a unique basic reference for design (minimum safety requirements/methodology/guidelines), which might be supported or not by more detailed and complex approaches, as occurs for traditional "fixed" foundations. Subsea structures could be regarded in the future as special components of the pipeline with a proper methodology to investigate their interaction with the seabed for the subsequent structural analyses.
Understanding Sliding Mudmat Behavior using Eulerian-Lagrangian Simulations
Authors: Hossain M. Kabir , Audibert Jean M. , Bryant John T. 
Published: April 2020

Abstract
At deepwater sites, skirted mudmats with a sliding mechanism have been the preferred choice to support pipeline or flowline end terminations (PLET or FLET) on soft clay seafloor to accommodate line expansions and contractions that occur during shutdown and restart cycles. The sliding mechanisms can experience line expansions of up to 4 m, or if it were to lock-up, horizontal forces in excess of 2,000 kN. The design and fabrication of sliding mechanisms for such large movements can often become challenging and costly. As an alternative, the industry is now designing mudmats that do not utilize sliding mechanism but rather slide directly on the seafloor, if necessary. While it is an attractive alternative and is gaining popularity, all aspects of direct sliding mudmat design are not sufficiently understood because of the complexity that arises from the interactions among the various components, i.e., flowline/pipeline, mudmat, jumpers, and the supporting soft seafloor behaving as one system. The design must ensure that the mudmat will not unduly sink, rotate or dig into the seafloor in the course of the back and forth sliding caused by many shutdown and startup cycles during the field's operating life. Therefore, it is essential to sufficiently understand the characteristics of the sliding motions and estimate as accurately as possible the resulting interaction forces in the flowline-mudmat-jumper-seabed system. This will allow the designer to avoid the risk of any system instability from incoherent component motions, or potential overstressing of connections.
This paper investigates the direct sliding behavior of the mudmat motions using realistic simulations of the flowline-mudmat-jumper-seabed system. The simulations rely on coupled Eulerian (soft seabed) and Lagrangian (flowline, mudmat and jumpers) finite element analysis (FEA) method. The simulations yield insight into the complex mudmat sliding behavior interacting with the jumper, the hydrocarbon line and the supporting seafloor. The simulations show that merely modeling the mudmat alone fails to capture the actual behavior of a real-life PLET/FLET's back and forth cycling on the seafloor, because for example, the restraints (and attendant stresses) at the flowline and jumper connections are not accounted for, or that slanting the sides of the mudmat reduces its tendency to self-embed decreasing connection stresses. The paper demonstrates that realistic simulations allow important visualization of mudmat interactions with flowline, jumper, and the seabed during the shutdown-startup cycles, and provide accurate determination of the associated critical responses.
Investigating the use of Geometric Shadowing and Thermal Radiation Mapping to Improve Fire Modeling in Offshore Facilities
Authors: Stahl Mike W. , Staszak Andrew J. , Clutter James K. 
Published: April 2020

Abstract
The offshore segment of the oil & gas industry has led and continues to lead the way in the use of computational fluid dynamics (CFD) in perusing inherently safer designs. Despite this, modeling focus has remained fixed on vapor cloud dispersion and explosion modeling. Typically, during the design process hundreds of various scenarios will be simulated using CFD through the later design stages. These studies will evaluate various sizes and locations of releases and clouds, changes in ignition location, release orientation, and evaluate loads at sensitive receptors throughout a facility. Extensive probabilistic and statistical calculations will be conducted to interpolate and extrapolate these results.
When it comes to fire modeling, the reliance is still with the use of simple phenomenological modeling. This is not to say that CFD fire modeling is not done, but rather when used, it is in a limited capacity with a focus on specific scenarios. These are usually the large scale, high consequence events. So, why don't we give fires the same treatment as explosions? This questions is particularly important, as facility risks are normally dominated by fire risks.
The simple answer is, that fires, their behavior, and the resulting hazardous effects are more complex and sensitive to variation than compared to vapor cloud releases and explosions. In addition, fire modeling is significantly more computationally intensive, i.e. more cost and time to a project. This makes running hundreds of scenarios and developing probabilistic maps to be used for interpolation and extrapolation much more difficult. A lot of work is being done to investigate improvements to CFD fire modeling, many of which are focused on simplifying the problems we solve and the physics we represent.
The biggest concern of fires, beyond direct impingement is thermal radiation. Thus, if we simplify the problem and focus on how thermal radiation is represented and calculated in fire models, we may be able to apply much more simplified modeling, while significantly increasing the quality of our solutions.
The focus of this paper will be on the use of geometric shadowing calculations to improve thermal radiation representations. This paper will investigate how these techniques can be applied to offshore facilities, identify where and how they could be applied, as well as look at shortfalls in which further research is required. With the goal being to work towards bringing fire modeling to the same standard of explosion modeling without the additional cost and schedule burdens to projects of traditional CFD fire modeling.
Design Wave Based Verification of Global Strength on an Unconventional FLNG Design
Authors: Bosman Theo 
Published: April 2020

One proposal FLNG uses tri-lobe tanks to store the LNG. This tank is supported by two cradles. Between the cradle and the tank loads are only transferred by the parts in contact. The contact area changes due to loading of the LNG tank, motions and deformation of the vessel. This paper gives an overview of the challenges in structural analysis resulting from this non-linear behavior and how to resolve them without loss of fidelity of the solution.
For spectral analysis the contact is to be linearized for the calculation of the stress RAOs and the response conditioned design waves. In performing the final structural analysis where loads from the hydrodynamic analysis are used, the contact problem is to be included. This results in an impractical processing time on one computer when considering all load cases. A superelement solution reduces the size of the model involved in the contact problem which for multiple solutions gives shorter wall times. However, these wall times are still impractical.
The comparison of the linearized model and the model containing the contact shows that the effect of the non-linear contact is localized. This opens the way for a staggered approach. The linearized model is used for a brute force evaluation of the structure taking all possible relevant time instances into account. A local model, one compartment with two tanks including the contact problem, is used to determine the stresses using loads and boundary displacements from the global linearized model.
Temperature Maintenance Philosophy to Optimise Electrically Heated Flowline Solutions
Authors: Alexis Wegner , Geraldine Trucy , Guy Mencarelli , John Leitch , Christian Geertsen , Geraldine Salque 
Published: April 2020

Abstract
The design of an electrically heated flowline is based on several thermal requirements, which significantly affect the design and the CAPEX of such a solution. In particular, the heat-up criteria which define the minimum duration - usually 48 hrs - required to heat-up a flowline from ambient temperature to the ready-for-restart temperature is often the most demanding one and drives the electrical system requirements in a very conservative way compared to the other heating criteria. The objective of this paper is to demonstrate how the industry could remove this heat-up requirement and adopt a "temperature maintenance operating philosophy" to optimise the design of electrically heated flowlines. Heat-ups from ambient temperature would still be achievable, in less than seven days.
This approach is particularly well suited to heat traced pipe-in-pipe, where the heat lost to the environment is extremely low. For these highly insulated flowlines, the temperature maintenance duty power is significantly reduced, compared to the required power for heat-up phases.
This paper investigates the potential benefits and the feasibility of this change in the design requirements. Initially, impacts on the overall heated flowline design and particularly on the electrical architecture have been assessed as well as the associated CAPEX reduction. Secondly, analyses of the corresponding operating procedures have been conducted to assess feasibility. Finally, OPEX aspects have been taken into account to conclude on the overall interest of the solution.
Case studies show that applying a temperature maintenance philosophy to heat traced pipe-in-pipe would lead to significant CAPEX savings thanks to optimised electrical system design. Regarding shutdown costs, although the results depend on the assumptions considered, the temperature maintenance philosophy appears preferable as it results in lower power consumption and shorter shutdowns, the majority of the time. Furthermore, fewer heat-up phases result in safer procedures with regard to hydrate melting risks while reducing the power applied reduces the electrical stress on the heating system.
All the assessments have been conducted based on Electrically Heat Traced Flowline (EHTF) technology however the same exercise could be performed for other electrically heated flowline technologies and could demonstrate similar benefits.
Tango FLNG - From Contract to Production in Less than 6 Months
Authors: Van Nuffel Frederik , Krekel Max , Verhagen Joris , Gilbert Thomas 
Published: April 2020

Abstract
Argentina is evolving from a natural gas importer to an exporter, thanks to the development of the Vaca Muerta formation in the Neuquén Basin. The Argentinean National Oil Company is still ramping up production, but already there is excess gas available for export in the form of LNG to international markets. The Caribbean Floating LNG (CFLNG) barge had been completed for another project, which unfortunately had been cancelled due to bankruptcy of the Client. In August 2018, the two companies met ‘over a cup of coffee’ to see if CFLNG could be deployed as a pilot production system for LNG export in Bahía Blanca, Argentina.
CFLNG was designed as a small-scale liquefaction system of 0.5 MTPA capacity, using pipeline quality feed gas. The paper will describe the design considerations made at the time, as well as the Engineering, Procurement, Construction and Commissioning activities to complete the unit for its alternate feed gas and location. Especially the latter was a major undertaking, since validating CFLNG’s liquefaction performance comprised loading 270 road trailers LNG into its cargo tanks, installation of a temporary LNG vaporization skid, to be able to complete the contractual full 72-hour liquefaction performance test, all while docked quayside at the construction yard.
Also, the paper will address the modifications made to the unit to moor it alongside an existing jetty in Bahía Blanca, to receive gas from shore, as well as the provisions made onshore for pre-treatment and pressure boosting of the feed gas.
After the initial contact with the end customer, due diligence inspections and engineering studies were performed on how CFLNG could be deployed in Argentina. Soon, both parties realized the unit was a good match. A contract was signed on November 20th, 2018: Caribbean FLNG was now to become Tango FLNG.
Site specific modification and reactivation works were carried out in China, where the unit was laid up. It was loaded onto a semi-submersible heavy lift vessel (HLV) close to Shanghai, late December 2018. In parallel, gas treatment and compression equipment was sourced and procured, and modifications to the jetty were completed. The unit arrived in Bahía Blanca in February 2019. After mooring up, commissioning activities were started, ultimately resulting in the successful delivery of a first LNG cargo on June 6th, 2019. Noteworthy detail is that Tango FLNG is moored to the same Jetty that was used to import LNG to Argentina for 10 years!
The project demonstrates that the FLNG concept is flexible and can be redeployed to other locations. The Start-up of Tango FLNG is the start of LNG export for Argentina.