bluuebunny/crossref_metadata_2025 huggingface dataset:
Mechanisms of Thermo-Mechanical Process on Grain Boundary Character Distribution of 316L Austenitic Stainless Steel
Authors: Zhang Ming Xian , Yang Bin , Wang Sheng Long , Wu Huan Chun
Published: March 2016

Grain boundary engineering (GBE) was carried out on 316L austenitic stainless steel with Thermo-mechanical processing (TMP), which was performed by unidirectional compression and subsequent annealing. The effect of TMP parameters including the strain and annealing time on grain boundary character distribution (GBCD) and the corresponding mechanism was investigated in the study. The results showed that high fraction of low-Σ coincident-site lattice (CSL) grain boundaries (about 55%) associating with interrupted network of random boundaries was obtained through TMP of 5% cold compression followed by annealing at 1000 °C for 45 min. The fraction of low-Σ boundaries increased with increasing the annealing time under all the experiment strain, but the mechanisms were different between the low and medium above levels of strain. Grains rotation and reaction of migratory boundaries might be the reasons of low-Σ boundaries growth in the strain of 5% and in the strain greater than or equal to 10%, respectively.
Semi-Active Reduction of Vibrations of Periodically Oscillating System
Authors: Michajłow Maciej , Szolc Tomasz , Jankowski Łukasz , Konowrocki Robert
Published: March 2016

Periodical vibrations are common phenomenon affecting a wide range of mechanical systems. Most frequently it affects machines designed to work in a steady-state conditions like: turbine, pump, rail vehicle, etc. In those kinds of machines it is always possible to decompose the system motion to basic average-speed constant component and oscillatory component. Usually the second term is treated as undesirable and various techniques are applied in order to minimize it as far as it is possible. These techniques refers to both the hardware selection – meaning the type of damping system (active, semi-active, passive) and the control method selection – meaning the damping system control method. Concerning the control methods, there are many algorithms available in literature devoted to transient systems. One of typical application is to use them in systems experiencing sudden, external force excitation. After destabilization of the system, caused by excitation, the role of the control algorithm is to restore the system stable position and additionally to reach the extreme of some additional criterion. Typical criterions are minimization of the time, of restoring the stable position, minimizing the consumed control energy, etc. On the other hand, considering the steady-state systems, especially based on semi-active damping elements, there are not so many control methods available.This paper focuses on developing the proper methodology for deriving the optimal control strategy of semi-active damping element, to be used in periodically vibrating mechanical system. The control strategy is developed on the basis of the Optimal Control Theory. Numerical computations are involved in order to solve the optimal control problem for the considered test system. Problem solution reveals the periodical nature of optimal control function.
Analysis of Selected Pressure Signal Descriptors Used to Control Combustion Engine
Authors: Bąkowski Andrzej , Radziszewski Leszek , Žmindák Milan
Published: March 2016

This paper analyses the option of using pressure signal new descriptors for controlling a selected object. Pressure signal deviations from the pressure mean values were selected to be the example descriptors. A compression ignition combustion engine fuelled with mineral-and bio-fuels was chosen to be the reference object. The pressure signal was recorded during the combustion process in the cylinder.
Topology Optimization of a Bounded Space for a Vibroacoustical Problem in a Low Frequency
Authors: Blazejewski Andrzej
Published: March 2016

The article deals with the problem of a space with vibroacoustical source generating inside specific conditions, which form a field of some values. All applies to an acoustic field in particular, characterized by an acoustic pressure or field of displacements in vibration problems. In general the field is described by specific dependent variable w(t) in all points of space, whose location are defined by coordinates r. The first aspect of this work relates to the modeling of an induced field, which can be alternative to finite element method (FEM) or boundary element method (BEM) in a low range of frequency. The second aspect is connected with minimization of some significant factor level related to dependent variable w(t) and subsequently to control field inside bounded space in order to get required state. In this work, it is assumed that the field distribution can be described by using modal analysis assumptions. Therefore, the dependent variable w(t) is defined by a modal expansion i.e. the sum over a set of a space’s eigenfunctions Ψ(r) (normal modes, characteristic functions) and time components (modal amplitudes, generalized coordinates). If the assumption of the highest values of acoustical or mechanical impedance of the space boundaries (damping properties of boundaries) is made, the modal coupling can be neglected. Such approach results in the vibroacoustical model being faster than alternative FEM or BEM models and suitable for the optimization procedure by using genetic algorithms, in the case when a computational cost is high. Thereafter, the topology optimization problem is formulated, where the influence of boundaries, represented by their impedance and the shape of space, represented by eigenfunctions are considered as the design variables. The genetic algorithm method is applied in order to find a minimum of objective function. In this case the function returns some functional value. As the result of the optimization a topology of the investigated space is obtained in the form of its shape and simultaneously configuration of damping properties of the space’s boundaries
Virtual Microphone Control for an Active Noise-Cancelling Casing
Authors: Mazur Krzysztof , Pawelczyk Marek
Published: March 2016

An active noise-canceling casing is very attractive for reduction of sound generated bydevices. Such casing can provide good noise reduction for low frequencies, where a passive barrierwould be too thick for practical use. The classical active noise control approach, where the goal is tominimize the sound pressure level around multiple microphones outside the casing can be used. However,it requires placing external microphones, what makes the overall technical solution not acceptedfor many applications. The active vibration control, where the goal is to minimize vibrations of allplates, requires only sensors on the plates. However, in this solution, in turn, noise reduction resultsare worse. This paper presents employment of the idea of the virtual microphone-based approach toimprove results from the system based on vibration sensors only, which are used to estimate acousticpressure at specific locations in the acoustic field. By using a two-stage structure, the system is tunedto reconstruct the same vibrations of the plates, which were present when the acoustic pressure wereminimized directly in the square sense. A laboratory active noise-canceling casing used for experimentsis made of 5 actively controlled aluminum plates mounted on a steel frame. It is passivelyisolated from the floor. On each plate, three electrodynamical actuators are installed. The controlsystem is experimentally verified and obtained results are reported.
A Comparison of Active and Semi-Active Sliding Mode Controllers Applied in Vibration Reduction Systems
Authors: Snamina Jacek , Orkisz Paweł
Published: March 2016

The paper presents active and semi-active vibration reduction systems applying sliding mode control systems. Calculations were completed for a laboratory system with two masses moving in a vertical direction. Support of the system is connected with the moving part of the exciter. The proposed system may be a simple model of many vibroisolated objects. In order to apply the control system of vibrations in the suspension of the upper mass, an actuator was implemented together with a spring. The role of the actuator was played by a linear inductive motor.Active and semi-active sliding mode controllers are proposed for the vibration reduction system. Theoretical analysis focused on applying of the sliding mode control in this system was carried out and, moreover, conditions to be met by the controllers were determined. The results of simulations and experiments are presented in tables and plots.
Progress in Bohai Offshore Heavy Oil Thermal Recovery
Authors: Liu Y. , Zou J. , Meng X. , Zhong L. , Wang Q. , Zhang W. , Zhou F. , Han X.
Published: March 2016

Although there is abundant heavy oil resource in Bohai oilfield, only limited oil production is obtained by cold production technologies in past. The practical challenges of thermal production technologies such as steam injection for offshore heavy oil produciton include the difficulty to install the large conventional steam generator onto the production platform, and the large heat loss during steam injection in the long wellbore.

In order to recover offshore heavy oil in Bohai Oilfield effectively in the limited production platform lifetime, a compact modular steam and gas generator was firstly introduced to generate steam, CO2 and N2 using diesel oil or natural gas as fuel, which could be injected into the offshore reservoir to enhance heavy oil production thermally. Usually, the temperature of generated steam could be regulated from 150 °C to 300 °C, and the operation pressure could be up to 20 MPa. The components including fuel tank, water treatment and air compressor could be easily resembled on the platform. At the same time, a compact modular steam generator was specially developed to for offshore steam injection process, in which N2 is usualy injected to make steam injection more effective to recover deep heavy oil reservoir.

For the typical heavy oil reservoirs in Bohai Oilfield, the injection and production parameters such as steam injection volume and ratio of gas to water (GWR in short) are optimized for cyclic steam and flue gas stimulation (CSGS in short) and cyclic steam and N2 stimulation (CSNS in short) based on experiment and numerical simulation. Then, the engineering aspects such as corrosion prevention, isolation tubing and wellhead were provided for offshore operation. Since 2009, there are more than 20 wells in stimulated by CSGS, and 2 wells in stimulated by CSNS.

In this paper, sheme optimization, engineering design and field test of CSGS and CSNS in Bohai Oilfield are introduced in detail. The result of field test shows that both the modular steam and flue gas generator and steam generator are feasible to operate on offshore platform and practicial to enhance offshore heavy oil production.
Using Engineered Fiber Pills to Cure Losses in Carbonate Formations - Offshore Deepwater Kenya
Authors: Awalt Michael S. , Mujuni Philbertus Deogratias , Johnson Carl , Joneja Galen , Meyer Arnoud , Bonsu-Gyimah Maame Serwaa , Hernandez Jonatan Torres
Published: March 2016

In line with the rise in remote deepwater exploratory work in East Africa, a major operator drilled a well in one of the two petroleum block licenses that they own offshore Kenya. The well was drilled in a water depth of 723m (2372ft) with the primary objective of establishing the presence of net pay and fluid type at specified stratigraphic levels. Prior to spud, the geological prognosis of the well indicated the presence of carbonate formation characterized with vugs and the imminent risk of severe losses were predicted. The drilling of this well indeed proved to be a challenging process.

Lost circulation while drilling and cementing continues to be a consistent problem in most deepwater operations that costs significant time and money. Firstly, the operator is faced with the inability to reach planned total well depth within the projected time interval, and secondly the necessary hydraulic isolation (cementation) covering problematic formations is not achieved.

In addressing the loss and weak zones, different approaches are used notably by reducing the hydrostatic pressure column, utilizing lighter weight slurries and reducing the penetration of fluids into fractures with the use of lost circulation material.

Losses were encountered in all hole sections below the 20-in casing just as predicted; estimated between 40 to 180 bbl/hr. As per a planned line of action, the mud service company pumped a range of lost circulation materials with different formulations, but none was successful. The executed approach was not effective in curing the losses and this resulted in total down time of 16 days of rig time causing the operator an additional $20 million over the AFE. Out of this additional cost, $0.34 million was due to mud lost into the formation and the rest was for daily operating rig cost.

The extent of the losses was so severe that it took a total of three engineered fiber pills and cement plugs placed at different depths before the operator could drill beyond the troubled zones. This paper is intended to cover the use of an engineered fiber and solids technology in a spacer system that was pumped ahead of cement slurry to aid in curing the losses.
Evaluation of Highly Retarded Cement Systems Under Exposure to Radiation Sources for Oilfield Applications
Authors: Lewis S. , Funkhouser G. P. , Gupta V.
Published: March 2016

Cement slurries have been designed to remain liquid for extended periods of time (> weeks) until exposed to a radiation source to provide a triggered activation mechanism. The cement setting occurs in two stages. First, a triggered setting of an aqueous phase system forms a stiff gel; then, the gel hardens further and develops strength because of cement hydration. The initial set can be accomplished by means of the triggered mechanism, while final engineering properties are provided by the hardened cement.

This paper describes the design and results of this initial work detailing the rheological behavior and mechanical properties of cement slurries on exposure to 14 MeV neutron radiation from an accelerator and ionizing sources currently used in wellbore logging, such as gamma radiation.

Additionally, other radiation sources are described in terms of their potential for use in a wellbore environment.

The triggered response of this system with relation to neutron energy and admixtures used in the cement design to impart direct response is discussed. Particular details are presented relative to usage of commercially available radiation sources and their efficacy in a wellbore environment. Correlations between energy output, calculated energy absorption, and cement response summarize the effects of this ionizing radiation on cement slurries containing admixtures designed to respond to such exposure.

The discussed cement systems employ monomer and polymer chemistry specifically selected for use with radiation triggered systems. Use of these chemistries in cement as additives and in other systems, such as spacer fluids or drilling fluids, is demonstrated.
Maximize Investment Rewards : Investigating the Effect of Field Characteristic on the Optimal Subsea Processing Solution
Authors: Sandy D. , Hasan Z.
Published: March 2016

Meeting the objective shared by all offshore oil and gas companies – maximizing reservoir production and recovery – is constantly challenged by a growing host of market issues and technology risks. When producing new offshore fields, operators face increasing challenges including deepwater, low reservoir pressure, heavy oil and long-distance step-outs. And it is not just in the development of new offshore fields that challenges are faced. Declining oil & gas production, increasing water cut with constrained topside facilities, increasing flow assurance challenges, growing operating costs, and integrity challenges due to aging facilities are all factors that can lead to field becoming operationally and economically unviable.

Subsea processing technologies are being adopted to address these challenges, especially in extreme environments. Subsea separation and boosting, for example, have not only proven their ability to enable complex developments with reliable performance levels, but have also delivered financial value.

In evaluating any subsea processing system, proven or new, investment rewards must be carefully investigated to ensure that the introduction of an advanced subsea solution will accelerate reserves, increase production and reduce costs. Field characteristics such as step-out distance, formation water production, fluid properties and water depth are some of the factors that must be assessed as part of the reward assessment.

This paper investigates how the step-out distance and formation water production affects the optimal subsea processing solution. Three different configurations will be considered; natural flow, subsea multiphase boosting, and subsea separation with separate gas and liquids pipelines.
Lightweight Drilling Riser Achieves 12 Years Successful Operation in Offshore Brazil
Authors: Lehner Jeffry K , Barker Ian , Walters David
Published: March 2016

This paper evaluates the application of lightweight drilling riser systems, comprised of aluminum alloy material that is significantly lighter than steel riser systems. The paper describes the system's design and specifications, and presents operational and maintenance procedures particular to lightweight riser use. The paper evaluates the comparative costs and benefits of upgrading a rig versus using lightweight alloy risers to increase water depth capability, and reviews the performance of these systems after more than a decade of operation.

The first lightweight alloy drilling riser system was deployed in Brazil in 20031. The initial aluminum alloy riser replaced a steel riser on a drill ship to reduce riser weight by 30% and increase the rig's water depth capacity by 2,000 ft. By the end of 2005, lightweight riser systems were deployed on another drill ship and two semisubmersible rigs, also working in Brazilian waters. By switching to lightweight risers, these units could operate in deeper waters without undergoing expensive upgrades. The lightweight riser systems on three rigs of the original rigs are still in use and continue to be in excellent condition.

As water depths increase, risers for drill ships and semisubmersible rigs become some of the most critical components of the drilling operation. Risers must be strong enough to maintain integrity during deployment and operation, be light enough to be handled and supported by the floating drilling unit, and be constructed of materials that resist corrosion while exposed to seawater. Lightweight alloy risers provide a means of increasing the water depth rating of floating rigs by as much as 50% without requiring expensive upgrades. Because of their lightweight construction, alloy risers are easier to handle, require fewer buoyancy modules, and can enable earlier generation floating rigs to increase their water depth capabilities, when compared to using conventional steel risers. The first generation of lightweight deepwater (DW) alloy risers has been used successfully for more than a decade while drilling in water depths up to 7,200 ft.
Optimizing the Lithology and Pore Fluid Separation Using Attenuation Attributes
Authors: Hermana Maman , Ghosh Deva P. , Sum Chow Weng
Published: March 2016

Ambiguity and pitfalls in amplitude interpretation to determine the hydrocarbon prospects is the most challenging problem in oil and gas industry, including in the Malay Basin Field. These pitfalls are caused by a dualism of the lithological and pore fluid effect on seismic amplitude. Many techniques have been proposed to solve the problem. However, the optimum separation of that ambiguity is still difficult to be achieved. The objective of this paper is to demonstrate new attributes derived from seismic attenuation - rock physics approximation as an alternative technique for lithology and pore fluid discrimination.

New attributes namely SQp and SQs have been developed based on seismic attenuation-rock physics approximation. Testing on model and real data sets from Malay Basin have been conducted.

The results show that the SQs attribute is sensitive to the water saturation changes, while the SQp is sensitive to the lithology changes. In well log, the SQs attribute has the highest coefficient correlation with water saturation compared with other existing fluid indicators, while SQp attribute has the highest correlation with gamma ray log. The cross plotting of these attributes show that the lithology and pore fluid effect are separated orthogonally to each other. The lithology differences are distinguished in the SQp attribute, while the fluid types are distinguished in SQs attribute. The gas sand is separable from shale background and wet sand easily. Furthermore, the coal effect can be distinguished clearly from gas sand. The implementation of those attributes on inversion result shows that SQs attribute is able to delineate the gas sand from wet sand that cannot be done by SQp attribute. Meanwhile, the SQp attribute can capture all the sand formations including gas sand and wet sand which is distinguished from shale background.
Reel-Lay Installation Approaches for Mechanically Lined Pipes
Authors: Tkaczyk Tomasz , Chalmers Martin , Pépin Aurélien
Published: March 2016

An increasing demand for subsea transport of corrosive constituents has generated interest in bi-metal pipes, which are made of a carbon steel pipe lined with corrosion resistant alloy (CRA). The CRA layer can be adhered to the backing steel pipe by either metallurgical or mechanical means. Reel-lay is an efficient installation method for subsea pipelines but induces plastic straining that may trigger wrinkling of the CRA liner in mechanically lined pipe (MLP), if reeling is not properly managed. Therefore, a suite of installation approaches has been qualified to enable safe reeling of MLPs. To provide evidence that a high fatigue performance can be achieved by reeled MLPs, a series of qualification tests has been undertaken. Finally, a thorough industrialisation of MLP manufacturing processes has been completed to ensure that defect-free MLPs can be manufactured in large quantities.
Combining Sonic While Drilling and Formation Pressure While Drilling for Pore Pressure Analysis to Reduce Drilling Risk: A Case Study in Offshore Vietnam
Authors: Dac The Nguyen , My Dung Doan Thi , Ahmed Aqil , Thai Ha Phung , Rehman Sadu-ur , Truong Son Nguyen , Hong Giang Khuc
Published: March 2016

The accurate prediction of pore pressure is important for safe drilling and can reduce financial risk significantly. The major focus during drilling in a high-temperature/high-pressure (HP/HT) environment is optimizing the drilling operation to mitigate risk by utilizing data such as sonic logging-while-drilling (LWD) and offset well information.

An offshore exploration well was being drilled in offshore Vietnam with drilling challenges of abnormally high formation pressure. In normally compacting sediments, water escapes through permeable sands or along fractures as overburden sediments build up, and fluid or pore pressure remains close to hydrostatic pressure. In such normally compacting sediments, under increasing effective pressure, porosity decreases and compressional velocity increases. However, if formation fluids cannot escape, for example due to the low permeability of overlying shales, then they bear part of the overburden load and hence become overpressured. These formations are called undercompacted, meaning they have a higher porosity than normally compacted shales. In overpressured shales, which contain pressured water, density is lower, porosity is higher, and compressional velocity is lower than normal.

Formation pressure can be the major factor affecting the success of drilling operations. If pressure is not properly evaluated, it can lead to drilling problems such as lost circulation, kick, stuck pipe, hole instability, and excessive costs. Therefore, knowledge of the pore pressure is of considerable value because it provides the means for improving drilling operations and designing better casing programs to reduce those risks. Using the data gathered from well logs, it is possible to predict the probable pressure profile that will be encountered while drilling. LWD data enable monitoring pore pressure very effectively; this pore pressure prediction can be continuously updated using LWD sonic and formation pressure while drilling (FPWD) to make optimal decisions for drilling operation. Once a suitable predrill pressure profile is established, it is monitored on the current wells with while drilling sonic and directly calibrated with formation pressures taken in sands.

In the offshore Vietnam well, pore pressure monitoring by LWD formation pressures and estimated pore pressure from LWD sonic data allowed drilling operations to be optimized. Employing this technique led to successful drilling without any incidences related to pore pressure. The computed pressures from LWD sonic matched the measured pressures obtained from FPWD. The real-time sonic matched the recorded-mode sonic closely. This technique could apply not only to the wells in this basin but also to the other wells in the locations with abnormal high formation pressure.
Reestablishing the Norms - Realizing Savings from Optimizations of Malaysian Drilling Industry
Authors: Sulaiman Muhammad Zarkashi , Hakim Hazlan A. , Hiep Nguyen Hong
Published: March 2016

This paper outlines the Low Cost Drilling (LCD) initiative rolled out in support of Cost Reduction Alliance 2.0 (CORAL 2.0) launched by Malaysia Petroleum Management (MPM), the regulatory body of PETRONAS, to propagate the practices of twenty six (26) Value Levers identified under four (4) key areas that could potentially lower the wells costs by Petroleum Arrangement Contractors (PACs) in Malaysia, with targeted savings of MYR 850 million from planned one hundred twenty five (125) wells in 2015.

Malaysian Oil & Gas industry has evolved from 3-4 PACs back in 1990s to over 25 PACs by 2014. Similarly, the number of wells drilled each year continue to rise to meet the production target. The average well cost has steadily increased annually due to inflation and increasing demand over supply for drilling tools and services. In 2014, Drilling & Well Intervention (DWI) section or widely known as MPM Drilling, under Petroleum Operations Management (POM) of MPM, has embarked on a study of the "Best In Class" over low cost wells delivered for the past two (2) years by PACs in Malaysia.

A total of twenty six (26) Value Levers were identified in the overall findings which could be categorized under four (4) key areas; 1) Planning & Well Design (12 elements), 2) Operational Practices (10 elements), 3) Fit for purpose technology (1 element), and 4) Logistics Operation (3 elements).

The initiative was rolled out in February 2015 by MPM Drilling in support of CORAL 2.0, where PACs were requested to identify Value Levers that could be applied to their wells with estimated potential cost savings. Twelve (12) PACs have responded with total targeted savings of MYR 850 million over 125 wells planned for 2015. This averaged to a cost reduction of around MYR 6.8 million per well. The progress savings will be monitored on quarterly basis against the initial target. Actual realized savings for 2015 will be confirmed in Quarter 1, 2016.
Overcoming Wellbore Instability Challenges in HPHT Field with Fully Coupled Poro-Thermo-Elastic Modeling: A Case Study in Hai Thach Field Offshore Vietnam
Authors: Hoang Son K. , Nguyen Son T. , Khuc Giang H. , Nguyen Duc A. , Abousleiman Younane N.
Published: March 2016

In this study, fully coupled poro-thermo-elastic geomechanics modeling of wellbore stability was conducted on high pressure and high temperature (HPHT) wells in Hai Thach field offshore Vietnam. The drilling environment is extremely challenging with formation pore pressure gradient of more than 17.0 ppg and formation temperature above 170°C near TD. Post-mortem analyses of drilled wells were carried out using an analytical poro-thermo-elastic wellbore stability simulator, taking into account the coupled time-dependent evolution of pore pressure, temperature, and stresses around the wellbore. The analyses revealed very narrow time-dependent safe mud weight windows that became narrower as time progressed. The HPHT environment created very challenging drilling situations. During drilling and hole cleaning, the flowing mud cools off rock formations, inducing tensile thermal stresses, and therefore reducing effective compressive stresses around the wellbore. As a consequence, the fracturing pressure is reduced when the ECD is higher due to circulation, increasing the chances of mud losses. On the other hand, during static mud condition the formations retain their very high temperature and compressive stresses, which require higher mud weight to prevent wellbore collapse while the mud pressure only equals the static mud weight, increasing the chances of shear failure. This study highlights the importance of accurate prediction of safe mud weight window before drilling as well as timely updates to the mud weight window during drilling. Furthermore, guidelines of good mud weight management practices to drill the HPHT zones with very narrow mud weight windows are also given. For example, when the safe mud weight window is too narrow and shrinks with time, a higher static mud weight might be required during openhole logging to combat borehole collapse. On the other hand, during hole cleaning with increased mud circulation rate and increased ECD, a lower static mud weight might be required to mitigate mud losses. Moreover, with the time-dependent safe mud window available, the drilling and logging program can be optimized to minimize exposure time and mitigate the damaging thermal effects on the mechanical stability of the drilled borehole.
Multiscale Modelling Approaches for Flexible Risers: Procedures, Capabilities and Demonstrations
Authors: Edmans B. D. , Guo T. , Zhang Z. , Pham D. C. , Sridhar N. , Stewart G.
Published: March 2016

Unbonded flexible risers are key components in many offshore oil and gas developments. To evaluate their performance, accurate mechanical models and efficient analysis techniques are required, both for life extension assessments of existing assets and for determining safe operational envelopes of new designs in deepwater environments. Due to the structural complexity of unbonded flexible pipes, predicting stresses and instability failures in these components remains challenging, inviting new approaches. This paper presents developments in the consistent linking of small scale (local nonlinear structural analysis) and large scale (global dynamic analysis). We describe sequential and integrated multiscale formulations aimed at improving modelling accuracy in a computationally feasible form. Principles and procedures for consistent multi-scaling are outlined based on established techniques used for the modelling of composite materials and structures that exhibit periodic symmetry and results are presented using these methods.

The predictive capabilities of the components of the multiscale analysis are explored, including: 1) a nonlinear beam-type finite element for riser representation; 2) a novel nonlinear section response model; and 3) a detailed finite element model computing component interactions. Verification of the integrated multiscale procedure is shown for a simplified case. The utility of multiscale models for investigating the conditions that lead to mechanical instability failures, such as buckling of the tensile armour wires is also discussed. The analysis procedures and model described in this article are proposed as methodologies for assessing fatigue damage, predicting instability failure modes and investigating the consequences of damage, such as breaking of tensile armour wires.
A Review: Operational Perspective into Cohesive Design of Offshore Facilities
Authors: Chandrasegaran D. , Noor M. H. Mohd , Sevah S. , Lok E. T.
Published: March 2016

Offshore facilities have diverse operational requirements due to the difference in user populations and the design intent of the facilities. Most facilities design is focused on the process requirements rather than the operations of the facilities. This paper focuses on the operational perspective in the design of offshore facilities. The term operational perspective covers all handling of materials, human machine interfaces and managing people in offshore facilities.

General operational concerns are described briefly. The operational needs such as handling provisions, human factors and regulatory compliance for the offshore facilities are summarized based on the current practices. Also, recent development and engineering practices in the offshore facilities operation are elaborated. Usage of human factors tools and others operational studies in design development activities are discussed as well.

As identified during the review, there is a common aim from operational and process that is to produce a reliable and safe facilities design. Any apparent gap between the operational requirements and current offshore facilities design products may result in low efficiency, higher risks exposure and lost time injuries. And these would be faced by the operator through the facilities life. In addition, there is a growing demand in the industry that stresses lower manning in the facilities, focused on operational needs and safety culture. Therefore, a cohesive approach during early design phase is required in addressing these gaps.

Systematic approaches are elaborated in this paper during early design phase to create better solutions and reducing modification works throughout the facilities life.
Pre-Tensioned Pipeline Bundles Design Challenges and Solutions for HPHT Field Development
Authors: Qadir K. S. , Morris K. , Goodlad M.
Published: March 2016

Objectives/Scope

High pressure-high temperature developments are on the rise globally as operators are pushing the current limits by investing in technology for the future, for e.g., Total West Franklin and ConocoPhillips Jasmine Pipeline Bundles. Pipeline Bundles have been designed and installed by Subsea7 for over 35 years globally and have been utilised where fluid transport requirements have made other technical solutions uneconomic. The Pipeline Bundle product has been incrementally developed over the years to the current pressure & temperature record of (604bar and 160°C). The next stage in development is to increase the temperature and pressure range for the product through the use of pre-tensioning. For HP/HT fields pre-tensioned Pipeline Bundles offers a technical and commercial key advantage, they reduce the build-up of unacceptable axial forces, mitigate the need for expansion/cooling spools and hence provide an economic fully integrated HP/HT solution.

This paper outlines the general benefits of Bundles and how mechanical and thermal methods can be used to set the pre-tension in-to the PIP (Pipe in Pipe) and their comparison. If EHTF (Electrical Heat Traced Flowlines) are integrated in the Bundle these might also be used to set the pre-tension and test the electrical heat trace system.

Methods, Procedures, Process

The base case for a comparative study is Total West Franklin which had design pressure of 604bar and 160°C temperature. Pre-tensioning calculations with varying combinations of pressure and temperatures are utilised to assess the impact on design of the Bundle based on the Total West Franklin Bundle. The effects of pressure and temperatures up to 1379bar and 220°C respectively are evaluated during the R&D project using calculations and advanced FEA with Abaqus. The paper will also outline the effect on the HP/HT design of changing the thickness of the production pipe by utilising displacement controlled and limit based design codes in combination with advanced FEA to assess the design, moreover requirements in regards to fracture mechanics are determined.

Results, Observations, Conclusions

In regards to HP/HT pre-tensioned pipeline Bundles, the design codes PD-8010 and DNV-OS-FlOl are not developed for Bundles and hence further work in developing an advanced FEA methodology for HP/HT Bundles, which is integrated with these codes would yield further benefit. A thick walled pipe might be beneficial for pressure containment and reduce overall stresses but in combination with higher temperatures also results in amplified compressive loads due to expansion. It can be established from results that a pipe with pre-tensioning and detailed flowline integrity analysis will enable design with higher temperature usage and optimise the pipe thickness.

Novel/Additive Information

It is expected that a technically feasible and economically advantageous solution for HP/HT developments will be realised for operators by pre-tensioned Pipeline Bundles.
Seismic Sensitivity Studies for Fixed Offshore Platforms
Authors: Sari Ali , Ramana Ekkirala , Cai Wenyu , Nguyen Hieu , Azimov Umid
Published: March 2016

Nonlinear dynamic response of offshore structures under seismic loading is a challenging and interesting problem to structural engineers. Fixed offshore platform under intensive ground shaking may undergo deformations well into the inelastic range. The first part of this paper discusses the seismic analysis methodology we developed considering the following effects (1) Soil radiation damping; (2) Soil-pile gapping; (3) Multi-level excitation and (4) direction of seismic loading. The second part of the paper uses case studies to demonstrate the methodology. These case studies involve a representative fixed offshore platform, Platform A. Platform A was analyzed against 10,000-year earthquake events. These 10,000-year events are based on actual earthquakes. The ground motion records were scaled up so that the resulting earthquakes would have a return period of 10,000 years. Time history simulations were carried out using the nonlinear dynamic structural analysis program USFOS. Results show that (a) the effect of soil radiation damping is not negligible; (b) Soil-pile gapping and soil radiation damping may cause opposite effects on the platform response; (c) Direction of seismic loading affects soil-structure interaction as well. The goal of the paper is to discuss and illustrate the methodology for advanced nonlinear dynamic analysis of fixed offshore platforms during 10,000-year earthquake events.
Novel Subsea Boosting Solutions to Increase IOR
Authors: Micali Salvatore , Abelsson Christian
Published: March 2016

During a market condition that is characterized by volatile oil price, there is a strong incentive in the Oil & Gas Industry on maximizing the hydrocarbons recovery from existing fields, rather than initiating new field developments.

For offshore deep water field applications, subsea boosting technologies are considered to be a solution to improve the field recovery, while also acting as enabling technology that allows for development of deep, harsh and stranded reserves, which otherwise deemed non-accessible.

This paper presents the performances and application area of two novel subsea boosting solutions developed by Aker Solutions: The boosting of condensate and oil as well as pressure increase by water injection through high pressure subsea pumpsThe subsea boosting of gas flow with associated liquid, though high performance subsea compression.

Special focus is given to the subsea centrifugal pump and compression technologies and how these new solutions can solve the existing challenges represented by providing high performance pressure boosting for both oil production with high gas content, as well as gas production with high liquid content.

Highlights on the key features of these novel technologies are provided, with specific focus on the benefits the technology brings to the market, like the high differential pressure generated together with the high efficiency and mechanical stability. These are all game changers for deep water IOR developments.
Conceptual Design of Offshore Surface Facilities in Marginal Field at Heavy Traffic Ultra Shallow Water Using Shallow Water Subsea Wellhead for CAPEX Optimisation in O-Field Development
Authors: Yananto H. , Girindra Y.
Published: March 2016

Some Oil and Gas fields in Indonesia, particularly in offshore have not been explored due to field economics. The absence of a thorough study of a potential development in the entire reservoir at a Production Working Area contributes the high cost of the development. The O-field would be the object of study with emphasis on the development of conceptual study for surface facilities. Some challenges that must be overcome for the development of this field, including the O-field is comprised of several small reservoirs and scattered. It is located in shallow waters and is in the area of export tankers for shipment of oil and other chemicals. The development of this field also becomes complex because its dependency to an existing facility.
Prediction of Individual Waves Based on Multi-Point Measurements
Authors: Wada R. , Mondal R. , Sakurai Y. , Takagi K.
Published: March 2016

We propose a system for predicting the near future wave elevation at the ship position using data observed around the ship. Our aim is to predict individual wave heights using ad hoc point observation system, such as drones, and utilize it to increase safety and efficiency of operation. This work extends the previous method for long crested wave prediction to the application for short crested wave. We elaborate on the prediction method with multi-points measurement data, and evaluate the computed prediction data for some cases to show the capability of our method.
Holistic Sand Management Methodology: A Multi-Disciplinary Team Approach to Cater Sub-Surface & Surface Aspects of Sand Production and Optimization
Authors: Gupta A. , Borhan N. , Kamat D. B. , Mat A. , Singh R. , Sunnapu R. , Baghdadi F. , Jadid M. B. , Gong M. , Madon B. B.
Published: March 2016

Sand Management refers to management of sand from its onset downhole till the handling of produced sand in the top side followed by the disposal while continuously taking safety aspects into account. It is apparent that a single discipline cannot execute this methodology as it requires a multi-disciplinary processed approach to safely produce, handle and dispose the sand. Moreover, for an operator managing multiple assets and each asset having similar issues, it is difficult to work in silos and this also increase the redundancy in tackling the issues. Furthermore, with increase in sand issues all across the regions, ad-hoc solutions became prevalent consuming more money and time.

To overcome the challenge of managing the produced and handled sand in an effective and systematic way, initiative was taken by the Operator to formulize the Central Sand Team (CST) involving various disciplines to centralize the entire effort. The objective was to avoid redundancy, standardize the efforts and efficient knowledge sharing. Each region further developed their own Regional Sand Team (RST) with representatives from each discipline. This team will then appoint a Sand Focal Points that will act as the liaison between CST and the RST. Roles and responsibilities were demarcated to both the CST and RST. The Central Sand Team (CST) focus is more on planning the strategy, developing guidelines or procedures, encourage knowledge sharing, being the centralized contract holder for few services and maintaining effective communication with regions' Sand Focal Points. Regional Sand Team (RST), on the other hand are the ones implementing the guidelines & documents and focus on sand related issues & mitigation more apparent in their own region.

The holistic approach of assimilating the entire sub-surface and surface disciplines under one umbrella to manage the sand proved effective in reducing the redundancy and coming up with effective solutions. The methodology has also proved a good knowledge transfer tool across disciplines. The sand issue which was usually tackled by individual disciplines is now being tackled collectively with proper data and complete understanding of the sand cycle.

The development of Integrated Sand Management Guidelines covers surface and sub-surface aspects. This is a unique concept resulted in a robust and comprehensive document. In addition to that, the sand erosion and transport softwarer is being developed as an application for sand erosion calculations and risk analysis. The methodology in itself is unique and can be blue print for many other operators with sanding issues.
Comprehensive Well Integrity Solutions in Challenging Environments Using Latest Technology Innovations
Authors: Alaref Omar , Rourke Marvin , Khabibullin Murat , Yakupov Alfir
Published: March 2016

The impact of corrosion on the oil, gas and geothermal industry is big and affects both capital and operational expenditures (CAPEX and OPEX). There is a growing public awareness and rising concerns with well integrity and health, safety and the environment (HSE).

One of the first steps for corrosion mitigation is to evaluate downhole tubular. The reduction of metal thickness leads to a loss of mechanical strength and structural failure. When metal pitting accelerates in localized zones, very considerable structural weakening may result from a relatively small amount of metal loss. Additionally, the alteration or loss of surface properties including erosion, increased fluid flow friction at the pipe surface, surface reflectivity or heat transfer across a surface, cause such weakness.

Corrosion evaluation using electric-line logging is of growing importance in the industry. Technologies that can evaluate multiple barriers are vital for cost-effective evaluations as rig time is saved by not having to retrieve the completion to evaluate production casings. This is the case especially in the offshore environment where the casing design is generally more complicated and consists of extra number of casing strings. Current technologies available include magnetic flux leakage or eddy current, or to some extent ultrasonic which has some limited capability of multi-barrier evaluation.

A multi-sensor electromagnetic corrosion tool (EM) has been developed especially for multi-barrier evaluations; the technology is based on pulsed eddy current physics. When combined with conventional multi-finger calipers and other tools such as radial cement bond logs or noise detection technologies, it offers a better understanding of well integrity.