bluuebunny/crossref_metadata_2025_split huggingface dataset:
Soil Parameters Required to Simulate the Dynamic Lateral Response of Model Piles in Stiff Clay
Authors: Brown Roger A. , Coyle Harry M. 
Published: June 2014

Abstract
Methods to obtain the soil parameters needed to simulate the dynamic response of a laterally loaded pile were developed in this research. Instrumented model piles of various diameters and embedded lengths were driven into stiff clay and tested laterally under free vibration conditions. Field data of bending moments and accelerations versus time were obtained.
The dynamic response of the model piles is predicted using an analytical solution. The nonlinear soil load-displacement characteristics are modeled with a modified Kelvin-Voight rheological model. The field data and the predicted response of the piles are compared and correlated. Using the correlation and laboratory triaxial tests on the soil, the soil parameters required to achieve satisfactory agreement between the field and predicted response of the pile are evaluated.
Results of this study indicate that the soil spring and soil quake are functions of the pile diameter. Together, these two soil parameters govern the magnitude and distribution of the bending moments with depth. The amount of soil damping is a function of the pile velocity or frequency of vibration, and is significant for the velocities and frequencies encountered in this study.

Introduction
Many types of offshore structures have recently evolved for many different purposes. The oil companies are perhaps the largest single industry intimately involved with offshore structures and their design. Drilling platforms are being located in deeper water as demands for oil are ever increasing. Storage structures for oil are being built below the ocean surface. Defense installations and weather retrieving devices are also constructed offshore. As structures are built farther offshore, the design complexities multiply as a result of the more severe sea conditions encountered.
Most offshore structures are supported by piles driven deep into the ocean bottom. In the design of these structures, frequently the lateral loads imposed by wind, waves, and ice are the critical design factors. These forces are repetitive, and are time-dependent. In some instances, such as a breaking wave, these forces could be considered impulsive. In the past, these dynamic effects have been given little consideration because of their complexities and the design engineer?s inability to cope with them. With the development of the high speed computer, it is now feasible to consider dynamic effects in design of offshore structures. Knowledge of the soil/pile interaction and water/ pile interaction is imperative if the dynamic response of the pile is to be accurately predicted. A review of the literature shows that much work has been done concerning the soil pile/ interaction under static lateral load conditions. However, very little work has been concerning the dynamic water/pile interaction.
Subsea Through Tubing Rotary Drilling
Authors: Garnier A. , Fraboulet B. , Andersen Stein Kristian , Bois A.-P. 
Published: June 2014

Abstract
The subsea Through Tubing Rotary Drilling (TTRD) is in principle a concept to construct new drainage points by utilising as much of the existing well path as possible, thus saving a significant amount of time and cost. A new fit for purpose system for subsea TTRD consisting of a small size (7") combined BOP/LRP solution, incorporating a surface BOP solution and a high pressure (HP) riser, will be delivered to Statoil in the 2.nd quarter of 2007.
This technology is applicable for all wells where the production from the "mother bore" has declined to a level where the option is to shut in the well and redrill to a new target. Furthermore, Statoil is currently funding the development of through-tubing multilateral systems, which will enable TTRD-sidetracks in producing wells and production from the two bores simultaneously. Traditionally a sidetrack has been done by pulling tubing and parts of the 9 5/8" (and possibly the 13 3/8") casing string(s), prior to a side track. By drilling the side track "through tubing" the cost will be significantly reduced.
The cost for a new well can be in the order of 40 - 50 million US $ when the subsea well slot is readily available, and even up to 70+ million US $ when a new well slot must be installed subsea. Utilising TTRD technology we envisage new drainage points to a cost in the order of 10 million US $. With a step change of this magnitude, the assets will be able to produce much more of the remaining oil from the reservoirs, hence increase the oil recovery.

Background
Statoil has to date performed 20 Through Tubing Drilling operations and all have achieved the technical goals. The two TTRD operations already performed on sub sea templates, through marine riser, were the world's first to be performed from floating mobile drilling units. The experience and know how obtained by these activitities has been systematically used in order to evaluate the potential for the TTRD technology in the future.
Statoil has identified "low cost drainage points" in sub sea fields as a major contributor to reach the ambition of 55% recovery from our sub sea fields on an average basis. From our platform fields we see that the recovery increases significantly with the number of drainage points constructed and well interventions performed. The same effect has not clearly been seen or realised in sub sea fields. Due to the high cost related to sub sea operations, Statoil has looked at novel and much more cost effective ways to construct the drainage points. One of these concepts is a new subsea Through Tubing Rotary Drilling (TTRD) concept. As can be seen from figure 1 the potential in TTRD operations subsea appears to be significant in terms of cost per drainage point.

Additional Drainage Point - Alternative TTRD
Figure 1 (available in paper): The TTRD potential
Note: The figure for a new well has risen substantially the last couple of years due to the extensively high rig rates.
Potential Failure Mechanisms in Floatover Deck Mating Systems
Authors: Byle Steven 
Published: June 2014

A Deck Mating System is entrusted to facilitate the transfer a topsides facility by Floatover method from a free-floating transport vessel to a fixed or floating substructure. These critical systems have moving parts, complex dynamic properties, and structural design considerations that are little understood by most designers. Yet, these systems may be employed with inadequate engineering, design and analysis. They may be manufactured and assembled by multiple, generalized contractors, rather than by a single, specialized vendor. And they may have their function tested for the first time during the actual Floatover operation.
There are inherent risks in this type of operation, and failures have occurred. As a result, some clients have grown more cautious. They have tightened specifications, limited procurement to specialized vendors, and required comprehensive testing of a fully assembled unit. Fortunately, no failure has yet resulted in the total loss of a topsides.
However, as there has been no dramatic, publicized failure, many clients continue to cut corners on this critical area and test poorly designed, engineered, and manufactured system in the field.
Primarily, this paper seeks to assist a designer, purchaser, or end user of a Deck Mating System by pointing out critical design considerations and by providing a set of recommended practices. The paper first provides a brief overview of the components of a Deck Mating System and their functions. It then outlines the potential design hazards, from obvious, catastrophic failures to often hidden failures to meet performance requirements. Finally, a list of recommended practices is provided in the form of an example specification. This paper draws from experience through 18 floatover operations and a larger number of design developments and engineering studies.
Recommended Practice on Riser Interference
Authors: Rustad Anne Marthine , Kalleklev Arve Johan , Sødahl Nils 
Published: June 2014

Abstract
A new recommended practice on riser interference (DNV-RP-F203) will be issued in 2009. The objective of the recommended practice is twofold:to recommend a methodology for engineering analysis, providing a rational design criteria and guidance for assessment of riser interference, andto achieve and document the industry consensus.
Assessment of collision between adjacent risers becomes more important with increasing water depth. The space between risers is limited both at the topside onboard the vessel as well as the riser gateway and at the seabed. Riser interference comprises complex physical phenomena, not yet fully understood, and research is still ongoing. When several risers/umbilicals are needed in a limited space, clearance between risers and risers and mooring lines should be documented.
The overall focus has changed somewhat since the draft was released for industry hearing in 2005. The 2005 version covered only top tensioned riser systems in steady current. The updated version covers all dynamic riser system including dynamic umbilicals and the focus is to document properly that no collision occurs. The scope is first of all to propose a framework for feasible analysis strategy and practical design procedures with focus on how to assess whether the risers collide or not. This paper presents the methodology for analysis, and the criteria which are the basis for the recommended practice.

Introduction
A more accurate methodology for assessing riser interference has become increasingly important when oil and gas exploration moves to deeper water. The risk of interference between Top-Tensioned-Risers (TTRs) increases with increasing riser length.
The general design practice is that riser collisions are not allowed under normal or even extreme conditions. The recommended practice considers analysis procedures and design criteria for riser interference assessment. The overall objective of the document is to recommend a methodology for engineering analysis, and to provide rational design criteria and guidance for assessment of riser interference. Riser interference comprises of complex physical phenomena, not yet fully understood, and research is ongoing. The aim is to achieve and document the industry consensus as per today.
The scope of work is first of all to propose a framework for feasible analysis strategy and practical design procedures with focus on how to assess if the risers collide or not. Whenever the terminology " risers?? is used it generally also applies for umbilicals and flexible risers in addition to TTRs. In order to derive a complete framework for feasibility and practical design procedures, the following topics need to be considered:overall framework and design approach;safety philosophy;environmental conditions and loads;analysis strategies and hydrodynamic interaction models, andacceptance criteria and fundamental requirements.
Frigg Decommissioning Offshore Work
Authors: Vivet S. 
Published: June 2014

Abstract
The Frigg Field was a natural gas reservoir that extends across the border between the Norwegian and the British sectors of the North Sea Continental Shelf. The Frigg Field was developed in accordance with the provisions of one agreement, known as Frigg Treaty, signed by the governments of Norway. Development of the Frigg Field took place between 1973 and 1977 and consisted of five plarforms with export of the gas to the St Fergus gas terminal in Scotland through two 32?? pipelines and one intermediate riser/compression platform located midway of the export lines. Three of the platforms were located in the UK water, the two others in the Norwegian sector and the United Kingdom. Under the provisions of the Frigg Treaty, Elf Norge now Total E&P Norge was defined as the Operator of the Frigg Field while Total Oil Marine now Total E&P UK was defined as the Operator of the gas export system.
The Frigg cessation offshore operation lasted from 2004 to 2009 resulting in the removal of all the platform topsides, all the jackets, all the infield and interfield sealines within the 500 m zone around the Frigg complex, all the external steel from de concrete substructures that were allowed to be left in place.
In line with the Frigg treaty, TOTAL E&P Norge was in charge of removing of the platforms located on the Norwegian sector (DP2, TCP2) but as well as the platforms located on the UK sector (QP, TP1, CDP1) of the Frigg field. The intermediate riser/compression platform (MCP01) was added by Total E&P UK to the scope of the Frigg decommissioning to be performed by Total E&P Norge.
In total 87000 tons of steel were brought back onshore for disposal either at Stord (72000t) in Norway and at Lervick (15000t) in Shetland.
Integration of Numerical Well Testing and Deconvolution Algorithm for Analyzing Permanent Down-hole Gauge (PDG) Data
Authors: Li Xiaogang , Qiu Maojun , Zheng Shiyi 
Published: June 2014

Abstract
The reservoir system in the real world is a dynamic system which the reservoir properties is changed with time. Considering the data in which PDGs record, one of the most defining characteristics is the inherent combination of short-term transients and long-term trendy. These characters permit dual application of these data to infer short-term effects (e.g., skin effect) and longer-term effects such as pressure depletion or changes in reservoir mechanism. The current approach to analyze the PDG data includes two directions. PDG data are analyzed with the traditional well testing approach to get the changed reservoir properties with respect to the transient character. With respect to the longer-term changes, PDG data are especially useful for history matching in the reservoir simulation.
Our approach tries to use the dual character of the PDG data. The transient character is mainly expressed in the log-log plot which is always used in traditional well testing. The long-term character is expressed in the Cartesian plot which is always used in the history matching of reservoir simulation. The numerical welltesting is approach to achieve the two direction. But the numerical well testing can not be used for the multi-rate pressure in dynamic system. Our idea is to linearize the nonlinear system to linear system with deconvolution. The deconvolution makes mistake to get the constant rate system response when the reservoir parameter changes because it can only be applied for linear system. This phenomena is used to diagnostic the critical point where the reservoir parameter changes. The critical points series divide the nonlinear system into different linear periods, and the numerical well testing is conducted to do forward modeling in every parts.

Introduction
The traditional well testing approach can get the changed reservoir information from the separated BU. However, this information can not guide the long term reservoir information because the DD part of PDG data has not been analyzed. The numerical well testing approach can help to analyze the complex geological model. But, it still suffers from multi-rate and nonlinear data. Currently, the deconvolution approach is introduced. This approach can transfer the multi-rate pressure into unit-response of reservoir in the linear system. However, the reservoir system in the real world is a dynamic system in which the reservoir's properties changed with time. The PDG data recorded from nonlinear system can not analyzed with current approach because the theory of current approach is based on the linear system. There are two approaches to analyze the nonlinear system data. The first approach is to linearize the nonlinear system into separated linear system. The current approach can be applied in every linear part. The second approach is to build a nonlinear model for nonlinear system. This study considers the first approach because the nonlinear model is hard to build and is not easy to solve.
Minimum Bending Radius (MBR) Tests of Flexible Pipes: An Experimental Approach Via Optical Motion Capture and Image Processing
Authors: Tanaka Rafael Loureiro , Gonalves Rodolfo Trentin , Ferreira Teófilo Barbosa , Rosetti Guilherme Feitosa , Pesce Celso Pupo , Fujarra Andre Luis , Godinho Carlos 
Published: June 2014

Abstract
A new optical measurement approach for minimum bending radius (MBR) tests of flexible pipes is presented. The method is based on an accurate tracking of the elastica through image processing. The new approach shows to be not only appropriate to the standard measurement requirements but also enables a comprehensive understanding of the structural mechanisms embedded in the problem. Samples were made from two distinct flexible pipes, with inner diameters of 2.5 and 4 inches.
A progressive set of tests was performed using five types of samples, obtained by dissecting each flexible pipe up to a certain layer. Sample 1 is made up with the internal carcass only. Sample 2 is constructed up to the liner (the internal plastic sheath covering the carcass). Sample 3 is mounted up to the pressure armor. Sample 4 is manufactured up to the external tensile armor. Sample 5 is made from the entire pipe, up to the external polymeric sheath.
The experimental methodology is given in detail. The samples are bent through the pulling of a cable linked to the extremities. The traction is measured by a load cell. A special stereoscopic system is used to optically obtain the geometry of the elastic line of the bent sample. From the measured elastica, the curvature is calculated. Results of bending moment at any section may be also calculated from the elastic line. In particular, bending moment vs. curvature, measured at the vertex of the arch, are calculated for each sample.

Introduction
Flexible Pipes are increasingly used for the transport of oil & gas, due to their flexibility, reliability and high resistance to the several types of loads inherent to this type of application. These loads include high pressures, both internal and external, tensions and curvatures and the flexible pipe resistance to these different loads is obtained by a construction with many component layers, each one responsible for the resistance to a given load (See Figure 2 for the different layers, represented by the different samples used in the test).
Since they are slender structures, a significant amount of bending is induced during their operation and must be taken into account in its design. This paper describes an experimental methodology to relate bending moment and imposed curvature, which is specially suited for the validation of a design methodology, since its results allow the developer of such methodology to have insights into details of the mechanical behavior of the tested structure, on a layer-by-layer basis. The test was applied to obtain the maximum curvatures that different layers of two flexible pipes can reach without damage.
Impact Loads and Protection of Subsea Structures on the Seabed from Floating Iceberg Keels
Authors: Ralph Freeman , Soper Steve , Stuckey Paul , McNeil Andrew , Barrett John 
Published: June 2014

Abstract
In iceberg prone regions, subsea substructures placed on the seabed are atrisk of impacts from free-floating and scouring iceberg keels. Here themethodology for assessing iceberg loads and two mitigation strategies aredescribed. The iceberg load model was an extension of previous work forestimating iceberg impact loads on offshore surface-piercing structures. Components of the algorithms were modified such that global design loads fromkeel contacts account for the change in contact location (i.e., longer leverarm in the vertical direction resulting in greater rotation effects). Theiceberg eccentricity model and the relationship between contact area andpenetration distance were also modified to account for iceberg keel contactswith a generic low profile structure on the seabed. One concept considered wasa single wellhead structure fitted with a special weak shear link incorporatedinto the design at the expected scour level. The shear link, or failure joint, would act as a mechanical fuse designed to fail in a combination of shear, tension and buckling during keel loading. The failure joint minimizes downholestructural response during iceberg keel loading on the production tree. Thedesigned failure mechanism would allow the well to be re-entered by protectingthe well casing from damage. Another concept considered was a steel truncatedcone structure installed over the well installation and fixed to the seabed byone of several identified foundation concepts. The protection structure absorbsenergy through crushing of the ice keel and encourages the iceberg to deflectaround and over the structure. The steel structure would be designed accordingto ultimate limit states accounting for energy absorption through elastic andplastic deformation of the structure. Design loads would correspond to anAbnormal Level Ice Event (ALIE) with an annual exceedance probability of 10–4. The size of the frame is governed by the size of the wellhead and tree system, Remotely Operated Vehicle (ROV) access requirements, and slope to encourageiceberg keel deflection. Piles may be the best option for securing a protectionstructure to the seabed, especially if a local vessel can be sourced to performthe installation. As an alternative to piles, using a drill rig to install wellcasings may be an option; however, market conditions for drilling rigs maydictate economic feasibility.
Physical and Numerical Modeling of a Sub-Surface Caisson for Protection of Subsea Facilities against Scouring Icebergs
Authors: King Tony , Ralph Freeman , Barrett John , Zakeri Arash 
Published: June 2014

Abstract
A simple, rectangular sub-surface caisson was evaluated using physical andnumerical modeling to develop a method for protecting subsea installationsagainst scouring keels of icebergs on the Grand Banks. This protection strategywas developed to assess the feasibility of the structure as an alternative tocostly excavations used to protect subsea equipment on the Grand Backs. Thescenario considered was an ice keel (i.e., iceberg) scouring over a buriedcaisson, avoiding direct contact but with minimal clearance. A centrifugetesting program, consisting of five tests, formed the basis for calibration ofa finite element model. The first four centrifuge tests were carried out withwater as the pore fluid in order to simulate drained conditions during thekeel-soil-structure interaction. In the field, fully drained conditions may notexist; hence the fifth centrifuge test was conducted using a viscous pore fluidto simulate the partially drained conditions. The numerical analyses wereconducted using the commercially available finite element software packageABAQUS. This study demonstrated that the Coupled Eulerian Langrangian (CEL)technique is capable of modeling slow keel-soil-structure interaction events insand. The numerical model performed satisfactorily in simulating the centrifugetests. The results indicated that such a system can potentially provide theprotection needed for subsea installations in ice infested waters. Althoughthis work was based on the conditions encountered on the Grand Banks, theconcept would be applicable to other regions. Future work should involveevaluating various ice keel-soil-structure interaction scenarios and attackangles, development of Inspection, Repair and Maintenance (IRM) strategies aswell as a detailed assessment of construction and installation issues.