bluuebunny/crossref_metadata_2025_split huggingface dataset:
Experimental Methodology of the Accumulated Plastic Strains (APS) Effect Evaluation on Steel Tube Umbilical (STU) Performance
Authors: Nascimento Filho Antonio Pereira , De Vasconcellos Daniel Luiz Bardanza , Oliveira J.D. , Godinho Carlos Alberto 
Published: October 2011

Abstract

Description of the Proposed Paper
This paper presents the results of a research project entitled "Experimental Methodology of the Accumulated Plastic Strain Effect Evaluation on Steel Tube Umbilical Performance", performed by Prysmian. The objective is to suggest an increasing of APS level in order to consider it on Steel Tube Umbilical design fatigue life. Experimental methodology through laboratory testings and prototypes in order to evaluate the actual influence of the high steel tube Accumulated Plastic Strains (APS) was used. Usually, APS can be accumulated during the steps of manufacturing and installation and may impose some restrictions for the steel tube umbilical performance and service life, manly when retrievals and post-installations are required. Normally in the market, it is stated that the level around 10% of APS does not down rate the steel tube performance, and the intention of this project is to increase this limit up to 30% of APS. For this purpose it was compared the pratical results from S-N curves between the welded steel tube and the theoretical calculation methodology according to international standard [1].
A more realistc figure regarding to the maximum level of APS will give to the offshore players a more precise idea of the feasibility to an umbilical project or requirement.

Methodology
For imposing APS on steel tube, the reeling and unrelling methodology was used. It consists of passing the tubes ½??x1.46 mm SAF 2507 from one reel to another and viceversa. So, the APS calculations consider the diameter of the reel and the number of reelings in order to achieve 30%. The samples were already welded in order to be more conservative. The calculations for imposed APS were based on [2].

Results, Observations, and Conclusions
From the comparison between experimental test results (30% APS welded samples) and DNV curve, it was observed that there is no significant variation on the steel tube fatigue life, when imposing such level of strain. The respective S-N curves are presented in Figure 1. Two experimental curves are presented. The green curve is the mean SN obtained from the experimental results, while the red one is the curve for a 95% confidence interval. Figure also presents the curve for steel tubes provided in the DNV-RP-C203 (in blue). It was also verified that the mechanical and fatigue properties are not affected. The final conclusion is that the level of 30% of APS can be used by the umbilical manufacturers with a certain safety factor.
The petroleum industry is still some uncertain regarding to the maximum level of APS, in face of that, this paper proposes and presents the validation tests for 30% of accumulated plastic strain on steel tube component for use in umbilicals.
Successful Qualification and Deployment of a High Pressure Drill Pipe Riser in West Africa
Authors: Camus Mathieu , Auclair Pascal , Horsburgh Barrie , Gallois Yann , Rohart Christopher , Miller Jim , Mfoulou Yannick 
Published: October 2011

Abstract
The Cameron/TOTAL Usan project team brought one of the first High-Pressure Drill Pipe Riser for Intervention Systems (DPRISi) to the African deepwater market in 2009.
Since July 2010, the string has been used offshore Nigeria. A total of 20 runs have been performed with this DPRIS, resulting in the safe and efficient installation of four trees. These trees have had no cleaning issues and no rust debris impacting operations.
Proper operating procedures implemented by field personnel have allowed for safe and efficient subsea DPRIS runs to date and provide confidence in future runs (38 more trees are planned).
Before DPRIS, most operators used conventional drill pipe available on rigs to install and retrieve the production adapter base and tree cap. While success varied, difficulties and risks arose using a hydraulic umbilical inside the riser, making it evident that technological improvement was needed to minimize interference between the pipe and the hydraulic lines.
The pipe delivered as part of this project, from VAM Drilling, are drill pipe risers with a propriety double shoulder connection and featuring a gas-tight metal-to-metal seal on the inner shoulder.
The standard offer for high-pressure DPR is 6-5/8" 0.5" wt and X-95 grade. VAM Drilling suggested this be changed to have a thick wall for corrosion allowance and higher grade for tensile strength, 6-5/8" 0.625" wt and G-105 grade.
The qualification program additionally covered all remaining requirements for full compliance to ISO-13628-7, which is believed to be a good certification level for such demanding and challenging operations.
The DPRIS system delivered in West Africa is a cost-efficient solution for subsea operations, workover applications and well intervention. This successful project, which provides technical and commercial value, is an example of how to implement a successful deepwater intervention business, not only in Africa but throughout the world.
Prevention of Fretting/Wear Damage in Pressure Armour Layers of Flexible Pipes Designed for High Pressure Applications
Authors: Fernando Upul Shanthilal , Dodds Neville , Leyland Jonathan , Graham Geoffrey , Sheldrake Terry H. 
Published: October 2011

Abstract
Pressure armour in unbonded flexible pipes is constructed using helically-wound profiled wires specifically designed to provide hoop strength; in high pressure applications, several layers are wrapped to provide the necessary hoop strength. During service, the wires in individual layers are in contact and move relative to each other due to dynamic flexing. Analysis of such interfaces is complex, as the contact between the layers is non-uniform, discrete and nonconforming. Discrete contact geometry often leads to high stress hot spots that can lead to regions of fretting/wear in the wire under certain conditions. Knowledge of the local interactions between individual layers and the ability of the pressure armour wires to withstand such local contact under applied dynamic sliding conditions is essential to guarantee the necessary integrity and durability of the pipe to withstand service pressure loading.
This paper discusses a pipe with two pressure armour layers. A finite element model has been developed to predict both the dynamic interaction between layers and the contact stick-slip behaviour between the wires under dynamic loading. The numerical results of this work, together with the fretting/wear damage behaviour of the wire material developed in a previous study, have been used to assess the fretting/wear damage of the pressure armour wires of the pipe. An evaluation method has been proposed to predict the safe loading envelope that would not lead to wear/fretting of the pressure armour wires.
The method involves the evaluation of subsurface stress distribution at the wire contacts in the pipe, which is used with material yield properties to predict the size of microscopic plastic zones. Loading cycles to crack nucleation are predicted using experimental data generated under similar loading conditions. A brief discussion is provided on the fretting damage behaviour of flexible pipes under service conditions.
A High Resolution Regional Ocean Model For Brazilian Pre-Salt Area: First Validation Results
Authors: Schoellkopf Jacques P. 
Published: October 2011

Abstract

The Project:
The PreSal 36 ROM JIP is a project for the development of a powerful Regional Ocean Model of 1/36 of a degree resolution, nested in an existing Global Ocean global Model, Mercator PSY4, at a resolution of 1/12 degree, with high resolution atmospheric forcing (every 3 hours).
The simulation outputs will be the 3 dimensional structure of the velocity fields (u,v,w) at 50 vertical levels over the water column, including geostrophic, Ekman and tidal currents, together with Temperature, Salinity and sea surface height at a sub-mesoscale spatial resolution.
Simulations will run in hindcast, nowcast and forecast modes, with a temporal resolution of at least 3 hours.

The Applications:
This Ocean current model will allow to perform detailed statistical studies on various areas using conditions analysed using hindcast mode, short term operational condition prediction for various surface and subsea operations using real-time and Forecast capabilities.

The First Results & Conclusion:
The paper will present the first publication of significant results of the project, in term of pre-sal zoomed model implementation, and high resolution model validation.

Significance
This project demonstrate the feasibility of obtaining accurate information for engineering studies and operational conditions, based on a "zoom technique" starting from global ocean models. Application can be transposed to any other area of interest such as GOM, North of the Golfe of Guinea (Nigeria, Ivory Coast, Ghana, etc.)
Real Time Horizontal Well Monitoring Using Distributed Temperature Sensing (DTS) Technology
Authors: Wang Xiaowei , Bussear Terry R. 
Published: October 2011

Abstract
The emergence of downhole distributed temperature sensing (DTS) technology has led to much better instrumented wells, allowing operators access to real-time temperature data leading to better well control and more efficient field management.
This paper will use field examples to demonstrate the benefits of this technology in two different applications: fracture monitoring during open-hole frac-stage treatment and steam distribution during Steam-Assisted Gravity Drainage (SAGD) process.
The migration from conventional cemented liner plug-and-perf techniques to packer-only stage isolation in open-hole has had a significant impact on the economics and efficiency of shale completions operations. As in-pay horizontal lengths get longer and the desire for increased unit fracture density increases, the concern for effective frac stage isolation increases.
The SAGD process has been widely used in thermal recovery industry for its high recovery efficiency. Effective steam utilization requires proper understanding of steam distribution along the targeted horizontal section.
Examples shown in this paper demonstrate the following benefits afforded to operators with access to DTS data in real time:Determine the effectiveness of open-hole frac-stage treatment during fracturing;View the movement of frac-fluids downhole within the target frac stage during fracturing;View the movement of fluids in previously fractured (lower) intervals during upper stage fracturing operations; andTemperature distribution along the well paths (injectors and/or producers).
Collected DTS data can also be analyzed in real time using in-house software tools developed for DTS visualization and interpretation. Data analysis and lessons learned from field applications are presented in this paper and focus on following four areas:Approximation of fracturing fluid distributionIntegrity of isolation packersImprovement in understanding of steam distributionImprovement of well integrity and identification of potential well completion breaches

Introduction
Distributed Temperature Sensing (DTS) is becoming an increasingly valued monitoring techniques when applied downhole in oil and gas applications. Acceptance has grown as a result of the increasing value that can be realized from such repeated, high-resolution well temperature profiles. Comparing with conventional production logging in horizontal wells, DTS technology is cost-effective and less risky. Unlike a conventional production log that provides only snapshots of the well performance, DTS can provide continuous real-time monitoring along the entire wellbore. Small temperature change can be easily detected by DTS. Such information can help operators to better understand their wells and reservoirs.
The Advancements of FEA in Confronting the Deepwater Pipelines Under High Pressure and High Temperature
Authors: Sun Jason , Jukes Paul , Wang James 
Published: October 2011

Abstract
This paper gives an overview of the latest developments of advanced finite element analysis (FEA) tools that are used for the design of subsea pipelines. It focuses on the deepwater and high pressure / high temperature conditions. The paper demonstrates through the use of FEA, that designs can be undertaken for complex scenarios that were not previously possible.
This paper includes three main sections. The first section looks at the ‘global’ analysis of pipelines using a set of highly non-linear finite element programs based on ABAQUS. These programs have been widely utilized for over ten years in oil and gas industry and for hundreds of field developments around the world, in various design stages, from pre-FEED, FEED, to final detail design. The programs are used to undertake the complex design cases, such as lateral buckling, upheaval buckling, pipeline walking; pipe-in-pipe (PIP); thermal buckle management; and pipeline span identification, as well as span stress and collapse screening. The programs have been calibrated against the observed pipeline structural responses in the field. The simulation process covers from installation to operation and can be expanded to pipeline span analysis, route curve stability, and pressure-thermal load fatigue assessment.
The second section demonstrates how FEA can be used to undertake ‘local’ modeling of pipelines to address local issues and provide verification and support for a reliable global pipeline design. Pipeline end structure behavior, thermal mitigation buoyancy and soil interaction, thermal mitigation sleeper embedment and installation tolerance, PIP inner pipe lock-in load, field joint stress/strain localization, and free span VIV analysis, are some typical applications. These works can be in component level or represent some local pipeline section. Such detail analyses ultimately relies on the ‘global’ FEA to provide trustworthy loading and boundary conditions.
This paper also presents the analysis strategies based on the project experiences, the lessons learned, and future improvement. The presentations include, the route selection versus thermal expansion and global buckling, the FEA modeling process (1-D, 2-D versus 3-D), the pipeline-soil interaction, the selection of mitigation for lateral buckling, and related design issues. The combination of these analysis advancements and extensive project experiences will provide the strong supports on solving the most complex engineering problems presently faced in the offshore industry, and in some cases have allowed significant cost savings to be achieved in the engineering.
An In-Situ Flow Cell To Highlight Different Mechanisms Of CaCO3 Inhibition By Green And Non Green Polymers
Authors: Duchene Aurelie , Neville Anne , Euvrard Myriam 
Published: October 2011

Abstract
Antiscaling agents are widely used to prevent scale formation in the oil and gas industry because scale's presence can lead to unscheduled shutdown and deferred oil production. The main problems result from the formation of scale on equipment. It has been shown that the mechanism of scale formation differed according to the scale nucleation that occurred in the bulk solution or on a surface.
The scope of this paper is to show, from experimental data, the effects of three different antiscalants on the growth rate of CaCO3 formation on a metal surface. The choice of which inhibitors to study was based on a survey of the environmental regulations that can be encountered in different parts of the world. A conventional phosphorous inhibitor was used as a reference (polyphosphinocarboxylic acid, PPCA) and contrasted to the performance of two environmentally friendly inhibitors (polymaleic acid, PMA, and carboxymethyl inulin, CMI).
The use of an in situ flow cell coupled with a video assembly and a microscope permits the real-time visualization of crystal morphology. Studies included looking at the surface coverage of the calcareous deposit and the number of crystals of CaCO3 formed. The effects of the scale inhibitors on the growth of calcium carbonate were studied after nucleation had occurred, in order to determine the effects of the inhibitors on calcium carbonate crystals already formed. A previous study was focused on the assessment of the inhibitors on the nucleation and growth steps. This paper is focused on the effects of the scale inhibitors on growing crystals which have been formed on a surface under uninhibited conditions.
The morphology of the crystals was found to be modified by the three inhibitors studied but to different extents. The addition of 4 ppm of PPCA and PMA significantly decreased the growth rate of the calcium carbonate crystals but the CMI did not modify it at the concentration range tested. This technique demonstrates that the efficiencies of scale inhibitors can vary according to the step in which the antiscalants were added (nucleation/growth).

Introduction
In the oil and gas industry, salts deposition is a problem widely studied because the presence of scale can lead to a loss of production, to formation damage and to the weakening of the equipment installations. Salts precipitation occurs when a system is not at ionic equilibrium. The equilibrium can be lost because of the changes of the temperature and pressure or with the introduction of incompatible brine. The supersaturation ratio S, characterizes the thermodynamic conditions of a solution and the equilibrium is reached when S is equal to 1.
Holistic Approach to Subsea Integrity Management & Reliability and their Application to Greenfield and Brownfield Projects
Authors: Botto Adriana , Rees Jacqueline , Hull Meghan 
Published: October 2011

Abstract
Industry momentum in recent years has been towards the implementation of risk-based integrity management (IM) programs for entire subsea systems (where subsea systems emcompass all hardware from the sand face downhole, to the top of the riser, inclusive of system interfaces, as defined in API RP 17N). This is evident from industry initiatives such as the Subsea Systems Integrity Management JIP (SURF IM JIP) and proposed revisions to industry codes of practice such as ISO 13628/12 "Dynamic Risers for Floating Production Installations" and API RP 17N "Subsea Production System Reliability and Technical Risk Management".
This paper presents a holistic approach to the development of risk-based integrity management programs, consistent with current industry best practice and JIPs that have advanced technology in these areas. The methodology balances the risk-based approach to maintaining asset integrity of the system as a whole with the reliability-based approach often adopted to define the preventative maintenance and sparing strategies for subcomponents of the subsea system.
A risk-based approach to integrity management is typically focused on identifying the IM measures required to manage the risk of catastrophic system failures with adverse safety, environmental, operational or reputational consequences. Reliability methods, in contrast, are typically focused on mitigation or preventative maintenance to avoid the unplanned failure of an asset's subcomponents (e.g. mechanical or electrical subsystems), the failure of which typically would not on their own lead to full system failure. A holistic IM program identifies the inspection, monitoring, analysis, procedural and preventative maintenance measures advocated to manage the integrity of the subsea system in its' entirety, balancing risk-based integrity management with reliability-centered maintenance.
The authors will demonstrate the implementation of this methodology for greenfield and brownfield projects (from the conceptual stage through to decommissioning). Emphasis is placed on how the integrity needs of a system mature over its lifetime to ensure a continuous, practical IM program.
Post-Macondo BOP Safety Upgrades
Authors: Baugh Benton F. , Vozniak John , Schmidt Nathan 
Published: October 2011

Abstract
In the pre-Macondo blowout era the offshore industry had an impressive record of safety, especially considering the complexity and magnitude of the work being done in relatively harsh conditions. The failures and spillages of Macondo have indicated that there are a number of safety areas which have not received appropriate progress in large part because history had not experienced a major failure of a BOP stack at that depth of water. This paper addresses several areas of technology which can be implemented to increase safety on new deepwater drilling BOP systems or retrofitted on current BOP systems in the field. These safety areas include better use of accumulator capacity, greater control over BOP stack functions, more redundancy of control, and improved ability to shear wellbore components. The ready availability of these safety upgrades and methods for full BOP Subsea operation and control, high volume ROV operations, and shearing drilling collars represent significant upgrades to Subsea drilling equipment safety systems post Macondo.

Depth Compensated Accumulators
Depth compensated accumulators represent a major safety improvement post-Macondo, although they were already seeing market acceptance before Macondo. The problem with accumulators on Subsea stacks is that more than 100 accumulator bottles would be needed instead of approximately seven for the depth compensated version1. Additionally, the depth compensated accumulators can be retrofitted on the ocean bottom by using multiple frictionless controls, also a major safety upgrade presented later in this paper.
The basic concept as seen in figure 1 is that a dumbbell piston has pressurized nitrogen in the top chamber and working fluid immediately below in a second chamber. The second chamber is divided from the third chamber by a central, stationary bulkhead. The third chamber is pressurized with environmental pressure, typically through an intermediate fluid for corrosion reasons. The fourth lower chamber is basically empty or a vacuum. This means that the pressure in the third chamber is not supported from below, but rather is mechanically added to the pressure in the second chamber. This means that at any depth, the pressure in the second working chamber exceeds environmental pressure by the amount of the nitrogen charge.
Increased safety impacts of depth compensating accumulators are:High nitrogen (or helium) pressures associated with conventional accumulators in deepwater situations are not required. As the piston area in chamber 2 is slightly less than the area in chamber 1, the nitrogen pressure never exceeds the working fluid pressure.Complex calculations are eliminated, the accumulators are simply run and operate subsea similarly as they operate on the surface.When the accumulator comes to the surface, dumping the nitrogen in the accumulators is not required.When the accumulator is re-run, the nitrogen does not have to be recharged,There is no danger that only some of the nitrogen banks have been recharged, but not all of them.