bluuebunny/crossref_metadata_2025 huggingface dataset:
Real Time Observing and Forecasting of Loop Currents in 2015
Authors: Cooper C. , Danmeier D. , Frolov S. , Stuart G. , Zuckerman S. , Anderson S. , Sharma N.
Published: April 2016

From February to June 2015, the Loop Current and its associated eddies were monitored at an unprecedented rate in southern Walker Ridge using traditional satellite sensors, satellite-tracked Lagrangian buoys, ship-mounted ADCPs, and moored ADCPs. In addition, a newly developed aerial system known as the Remote Ocean Current Imaging System (ROCIS) was flown almost daily, measuring surface currents at roughly 1 km spatial resolution over 125,000 km of combined transects. During the five-month period of observations, the Loop was extremely active, shedding one large and a second smaller anticyclone, and generating numerous intense cyclones. The extensive observations offered the opportunity to improve model initialization and thus the overall accuracy of the operational ocean current forecasts. An example is given of the substantial improvements that can result when more accurate observations are feed into the model initialization process. Perhaps just as importantly, the synoptic observations provided forecasters with an unprecedented view of the important fronts and features dominating the local flow field. The paper reviews the forecast accuracy from a numerical model and the subjective predictions from two forecasting groups with access to the model. The results show the model has about equal skill to the best of the forecasters. Mean 48-hr forecast error for the best forecaster was only about 0.2 kn but the variability of the error was substantial, 0.6 kn, with a correlation coefficient of only 0.65. In short, forecasting currents when the Loop or eddy fronts are nearby is challenging even with intense measurements and modeling. Those who depend on such forecasts should maintain realistic expectations regarding the forecast accuracy.
Impact of Field Measurement and Advanced Analysis on Baldpate's Continued Service Integrity Management Plan
Authors: Moslehy Y. , Kemp D. , Kitson M. , Litton R. , Sheppard R.
Published: April 2016

A Structural Integrity Management (SIM) program plays a substantial role in managing structural risks and reducing expensive deepwater in-situ repairs. Inspection and operating decisions and costs are significantly affected by what is defined in a SIM program. Baldpate compliant tower in particular features an innovative structural system and is among the tallest structures ever built. It is a valuable deepwater asset that needs a SIM program backed by a strong technical foundation to provide confidence that continued service and potentially expanded operations can be safely achieved.

Earlier studies had shown that fatigue sensitivities at critical locations could potentially limit Baldpate's useful life beyond the original 20 year target. This was mainly due to the conservatism inherent in the spectral fatigue approach which did not capture the innovative and highly dynamic features of the Baldpate tower. In order to better understand the dynamic characteristics of this unique structure and accurately model the tower, a field measurement campaign using 3D accelerometers was carried out. The measurements were then used to benchmark and adjust the computer model. A time-domain rainflow fatigue analysis was utilized to capture the compliant response of the tower for both fatigue seastates and three large storms which have affected Baldpate. This showed that fatigue sensitivities are not limiting factors for continued service of Baldpate, and the areas of fatigue sensitivity were incorporated into a long term SIM plan to focus future inspection and monitoring efforts.

This paper provides details on the study performed for the Baldpate structure using field measurement, a rainflow simulation and its contribution to the development of a long term, risk based SIM plan. The behaviors of several unique structural components, such as stress concentration factors at atypical connections, gap behavior and friction lock-up at the guided axial tubes, were also considered. SIM options for these unique structural components are discussed, including underwater inspection methods and on-site dynamic motion recording. These efforts resulted not only in a more promising range of fatigue lives than previously calculated, but also identified areas of focus in support of a risk based SIM and associated inspection plan to support continued service through the asset's viable economic life. This approach is enhanced by a real-time monitoring plan to measure the dynamic characteristics of the tower under different load conditions to indicate when certain unique structural characteristics (e.g., axial tube motion within the guides) would affect the fatigue life of critical joints in the Baldpate tower.
Design and Qualification of Direct Electric Heating Riser Cable for Deep Water Applications
Authors: Clasen Torunn Lund , Slora B. R. , Karlsen Stian
Published: April 2016

Direct Electrical Heating (DEH) is a field proven technology for preventing wax and hydrate formation in subsea flowlines. The technology is currently in use for heating more than 30 flowlines ranging up to 42 km in length, and has been installed in water depths down to 1070 m.

DEH is an attractive solution for addressing flow assurance challenges in deep waters. One main challenge related to DEH in deep waters is to design a dynamic riser cable for supplying power to the subsea DEH system. The challenge is related to high topside tension caused by the weight of the cable, and the risk of overloading the conductors. This paper discusses the ongoing work related to qualifying a DEH riser cable design for deep water applications.
Eni's Global Program on Production Data Management Sets the Stage for an Effective Reservoir Management & Production Optimization System
Authors: Drago Antonio , Vignati Emanuele , Bergamaschi Barbara , Calzari Marinella , Morales Fernando L. , Fumey-Humbert Frederic , Toyas Christos
Published: April 2016

The aim of an ongoing implementation of a global production management system is to support an operator in its continuous efforts to improve its affiliates' oil and gas field operations. The main objective of production operations is the maximization of the project returns, which involves the optimization of well production rates, increased of reservoir recovery, and the reduction of the associated expenses. This objective can only be achieved through the effective use of accurate information about the production system's performance (including its reservoirs, wells, and surface and process facilities).

Due to the massive amount of information generated daily in oil and gas fields, specialized software tools are essential for data gathering, cleansing, and storing and for meaningful dissemination, consumption, and analysis of the data to aid decision making.

Aware of this critical need, starting in 2008, Eni launched an ambitious program to implement a production data management system (PDMS) that allows specialists to properly perform well and hydrocarbon production accounting, run specific workflows to correctly analyze the information, and effectively support the operations in several key affiliates around the world.

The interconnected system has proved to be very valuable for strategic planning and informed decision making, considering the size and the remoteness of the operations and the need to assure that operations in the assets are carried out in the most efficient way possible.

The current scope of the PDMS global program includes completed implementations for 12 affiliates and the monitoring of more than 4,000 wells. This paper describes the program's objectives, the achieved benefits, and the vision on the way forward. The paper also addresses some of the main problems encountered during the execution and enumerates the main lessons learned.
Extending the Lifetime of Oil and Gas Equipment with Corrosion and Erosion-Resistant Ni-B-Nanodiamond Metal-Matrix-Nanocomposite Coatings
Authors: Murugesan Sankaran , Monteiro Othon R. , Khabashesku Valery N.
Published: April 2016

The increasing pressure to eliminate hard chromium in oil and gas applications because of environmental concerns related to hexavalent chromium has fueled the need for substitutes with comparable economics and performance. Nickel (Ni) presents a viable alternative coating material, which is widely used in industrial applications over the past five decades because of its unique characteristics in improving resistance to corrosion, abrasion and wear. Performance of Ni-based coatings can be further improved with the development of metal-matrix-nanocomposite coatings (MMnC). This paper presents the development of a new class of MMnCs prepared by electrolytic deposition. The nanocomposite coatings are formed by the simultaneous impingement of the nanoparticles onto the growth surface and the envelopment of said particles by the depositing Ni ions. In this new process, the metal matrix comprises Ni-B compositions produced with a nontraditional Boron (B) source, which enables higher B-contents in the matrix, resulting in superior hardness and resistance to corrosion.

Incorporation of diamond nanoparticles into the matrix improves resistance to wear without negatively affecting the corrosion resistance. Dispersed nanodiamond decreases the grain size of Ni-B matrix and improves the mechanical properties of the coatings. Ultimately, size, nature and content of particles dispersed in the matrix determine the properties of the coatings. This paper describes the impact that Boron and nanodiamond incorporated in the matrix have on the growth, microstructure, corrosion and mechanical properties of the new class of metal-matrix nanocomposite coatings. Experimental results also show that this material outperforms current commercially available electroless Ni-B coatings. The novel coatings presented extend the lifetime of equipment used in corrosive and erosive environments in the exploration and production of oil and gas.
Achieving Savings Through Reliability Using Real Time Data
Authors: Pritchard David M. , York Patrick , Roye Jesse
Published: April 2016

Historically, the drilling industry has utilized real time data (RTD) for improving drilling efficiencies, documenting occurred events, and reactive decision-making. RTD should promote situational awareness with respect to wellbore instability and hazards. Drilling trends identifiable in RTD change over time as abnormal trends leading to hazards and rarely occur instantaneously. These destabilizing events such as cuttings loading, barrier compromise, kicks, pack-offs, wellbore collapse, or other mechanical and pressure-related causes, whether in rotating or flat-time operations, can be avoided or mitigated. Accepting these hazards as a necessary outcome of drilling operations can be a dangerous proposition and denies risk accountability.

Enhancing the systemic approach to process safety represents a paradigm shift in the industry and requires changing behaviors through proactively managing and controlling the pace of the drilling process. A new paradigm suggests the use of a deterministic, physics-based model of real time force-balance in the wellbore during the construction process. Identifying the trends of these forces become predictors of hazards. Mitigating and correcting the trends, in real time avoids process safety failures and consistently results in improvements in non-productive time (NPT) and removable lost time (RLT), notwithstanding the large associated costs. The drilling trend behaviors that predict hazards can facilitate leading as opposed to lagging Key Performance Indicators (KPIs). The new paradigm suggested enables hazards avoidance and thus significantly reduces the costs of drilling. This paper describes and explains these predictive techniques as well as offers suggestions for industry training with respect to surveillance and hazards avoidance using RTD simulators, much as airline pilots would use for continual training.
Systems Approach to Product Design for Ultra Deepwater Lower Tertiary Completion Systems
Authors: Pateder Robbie R. , Schrader Kirby G. , Allen Jason , Manera Michael
Published: April 2016

This paper describes how a systems engineering approach was used to develop completion technology targeted for the ultradeepwater Lower Tertiary Trend. The paper further describes how an integrated completion system was developed for this market from concept through qualification by an integrated product team. The integrated product team (IPT) is cross functional team that was assembled with the objective to develop a sandface to safety valve integrated completion solution. The approach began with a needs assessment including a reservoir study of the Lower Tertiary trend and voice of the customer exercise to gather information and define market problems. The team used a Design for Six Sigma methodology to develop system concepts and develop integrated system requirements. The concepts were vetted and refined into an integrated completion system that was designed, tested and qualified in a dramatically reduced product development cycle time.
A Sensible Approach to Subsea Pipeline Route Determination – Moving from Hand-Drawn Routes to Geologically-Constrained, Least-Cost Optimized Paths
Authors: Devine Christine A. , Haneberg William C. , Lee Hoseong , Liu Meng-lung , Chang Gwo-ang
Published: April 2016

Pipeline routes have traditionally been selected in the early stages of prospect development, using low-resolution datasets, with minimal consideration for seafloor and shallow subsurface geological conditions, and rudimentary rules about seafloor gradients and pipeline curvature. We describe advantages of a modern GIS-based approach using least-cost path optimization over a composite geocost surface, which provides a structured framework for quantifiable decision-making, incorporates formal risk assessment as part of the route acceptance process, and forms the basis for a forthcoming industry guidance document. The workflow that we propose comprises: 1) geophysical data acquisition, geotechnical investigations, and geological studies during the initial stages of development to evaluate potential pipeline routes; 2) systematic evaluation of geological, geotechnical, ecological, and cultural factors that determine pipeline route suitability; 3) the classification and weighting of all identified geohazards and constraints to develop a geocost composite map; 4) determination of an optimal route using least-cost path optimization within a geographic information system; 5) risk assessment of the least-cost route; and, finally, 6) route acceptance. The classification and weighting of component hazard maps, as well as the risk assessment, are best performed collaboratively by a multi-disciplinary team that includes expertise in marine engineering geology, geotechnical engineering, pipeline engineering, marine ecology and archaeology, and health, safety, and environmental personnel. We will demonstrate a step-by-step application of the method, which has already been used for pipeline route determination on geologically challenging deepwater projects. If geohazards are not identified in early stages and used to guide route selection, changes to the original pipeline route or mitigation - either of which could affect schedules and budgets - may be necessary. This method is relatively new to subsea pipeline route determination, however, it offers important advantages over previous methods and can be applied starting in the earliest conceptual phases of field development, iterating if necessary, as new information becomes available.
Non-linear Dynamic Site Response Analysis for Subsea Pipeline and Structures Seismic Design Considering Variable Site Conditions
Authors: Hossain Jubair , Suroor Hadi
Published: April 2016

Site response analysis is essential in assessing the offshore pipeline integrity as well as the stability of subsea structures during an earthquake event. Depending on the functionality, the length of offshore pipeline can be tens to hundreds of kilometers running through different underlying soil conditions as well as traversing submarine slopes. Therefore, it is important to identify the effect of variable site conditions on the earthquake response to accurately predict the stability of offshore pipeline as well as subsea structures. A study was undertaken to determine the ground responses along an offshore pipeline route across escarpments and connected to subsea structures at the termination points. The pipeline route was divided into multiple segments depending on the soil variability. Due to high site seismicity, the soft soil is susceptible to high shear strain during strong earthquake shaking; thus requiring non-linear dynamic site-response analysis to accurately capture soil dynamic response. A finite element based non-linear site response analysis was selected for the entire pipeline route. The dynamic site response analyses were carried out using PLAXIS 2D and the soil behavior was modeled considering non-linear variation of stiffness and damping with shear strain. The input ground motions to the dynamic site response analysis were site specific stiff soil earthquake motions scaled to Abnormal Level Earthquake (ALE) and Extreme Level Earthquake (ELE). The segment-specific response spectra and time histories at mudline were developed as input to the seismic design of pipelines and subsea structures. Despite a stable escarpment during a seismic event, the site response analysis showed localized high deformation which can significantly affect the pipeline seismic response. Considerable variations in mudline response spectra was observed depending on strength, thickness and depth of soft soils. This paper provides an overview of dynamic site response analysis performed for an offshore site, and focuses on the effects of variable ground models, as well as escarpment on the seabed level seismic motions for subsea pipeline and structures seismic design. The importance of accounting each of these effects in the development of a robust and safe seismic design has been highlighted.
Quest for the Perfect Dry Tree Application, Summary of RPSEA and DeepStar Projects over the Last 10 Years
Authors: Head W. J. , Pappas J. M.
Published: April 2016

Dry trees (DT) provide vertical well access from the water's surface with well bore tools, and are especially useful for speedy interventions. Lower potential CAPEX helps, thus avoiding some of the more complex deepwater seafloor construction projects. However, in the ultra-deepwater, risers for DT become the demons of necessity. Deepwater pressures and high formation temperatures make for thick walled pipe. All of this requires large, extensive kit, and a challenge for existing DT designs such as a spar or a tension leg platform (TLP).

Riser weight controls DT design choice. The common top tension machine is limited to about 35 feet of the up and down motion of the sea. When industry designed mobile offshore drilling units (MODU's) larger with deeper draft to offset vertical riser motion, the structure itself became a cause of unwanted motion and vibration. After hull considerations, research focused on structural vortex induced vibration (VIV) and vortex induced motion (VIM), riser motion onboard, and lower weight risers.

Deep draft designs studied by RPSEA and DeepStarTM showed VIM and VIV reactions through simulated computer and tow tank testing. Such designs require mitigation strategies. Paired column semisubmersible floating vessels (PC-Semis) can be designed with some control over column size as part of the mitigation. Critical steps to complete are as follows: Performance on the drill/production aspects, especially of the risers relative to fatigue, and safety in both normal weather and under extreme conditions.Well bay designs to allow simultaneous ongoing drilling operations while producing [with risers], and keeping the area safe for workers.

The results of nine years of study have shown that there were no major technical show stoppers. Since the original quest was to save money, the objective has become a more difficult moving target. Lessons learned suggest a possibility to use deep draft dry tree (DT) designs as less costly wet tree vessels.
Understanding Reservoir Fluid Dynamic Processes by Using Diffusive Models
Authors: Zuo Julian Y. , Mullins Oliver C. , Jackson Richard , Agarwal Ankit , Ayan Cosan , Wang Kang , Chen Yi , Pan Shu , Elshahawi Hani , Dong Chengli , Herold Bernd , Kumar Sanjay
Published: April 2016

Downhole fluid analysis (DFA) has successfully been used to delineate reservoir connectivity and fluid properties and to understand the origins of many complexities in oil reservoirs with the Flory-Huggins-Zuo equation of state (FHZ EOS). Equilibrium asphaltene gradients strongly imply reservoir connectivity, with fluid equilibration often taking tens of millions of years. However, reservoir fluids often demonstrate complicated compositional gradients from undergoing dynamic processes such active late gas charges, biodegradation, and water washing. In this paper, a simple 1D two-component diffusive model with analytical solutions is developed for taking into account dynamic processes in oil reservoirs. Two field applications of the developed diffusive model are active gas charging and biodegradation to better understand these dynamic processes.

In the first field application, an active late gas charge results in huge nonequilibrium gradients in several fluid properties including API gravity, gas/oil ratio (GOR), saturation pressures, and asphaltene content (color optical density) measured by DFA and surface laboratory analysis. Because the reservoir is not in equilibrium, these fluid property gradients cannot be modeled by the equilibrium EOS model. Thus, a diffusive model is needed to account for the large GOR gradient. The diffusive model predicts the large variations of GOR gradients successfully. The asphaltene gradient is evidently under control of convective currents induced by the gas charge. The exact nature of this process is currently under investigation. The asphaltene gradient is consistent with the predictions by the FHZ EOS with the assumption of asphaltenes locally in equilibrium with the local fluids described by the diffusive model.

The second field application is biodegradation occurring at oil/water contact (OWC). Compared to the predictions of the FHZ EOS, it is observed that the upper half of the oil column follows an equilibrium asphaltene distribution well. However, a much larger asphaltene gradient is found in the lower half of the reservoir, which gives rise to a huge (8×) viscosity variation and affects production. The measured asphaltene distribution in the whole oil column can be described nicely by the diffusive model along with the FHZ EOS. The diffusion of alkanes to the OWC (where they are rapidly consumed) is a control step. The consumption of alkanes at the OWC reduces the oil volume and increases asphaltene content and viscosity. Petroleum system modeling predicts initiation of reservoir charging in the Eocene matching the diffusive times required in the FHZ EOS modeling.
Source Control is a Viable Solution for Shallow Water Blowouts: Case Histories and Discussion
Authors: Derr Douglas , Cramm Carl J. , Garner John. B.
Published: April 2016

This paper presents two case histories providing insight into source control operations at shallow water depths. The first case history discusses a capping procedure at the seabed in a water depth of 80 ft. Debris on the seafloor was cleared and a new platform was installed, incorporating the remaining legs of the damaged previous jacket up. Once the well was successfully capped and diverted, the drillstring was snubbed into the flowing well, which was then killed by means of a dynamic kill operation. The second case history discusses capping a burning high pressure gas well on a platform. Debris was cleared and removed from the platform, and eventually the well was capped and flowed to a pipeline.

This work highlights how source control options should be considered and evaluated as part of emergency response plans for jackup rigs and platforms. Proper planning, organization, and task management are fundamental to a safe and successful operation.
Exploring Deep Water Applications for Offshore Renewable Power Systems
Authors: Worrall P.
Published: April 2016

The increasing power output of today’s renewable energy generation devices mean there is a growing need for affordable, dynamic, high voltage subsea power cables. Serendipitously, these solutions are directly relevant to the offshore oil and gas industry, specifically when coupled to power distribution hubs for processing and boosting at the evolving subsea factories.

It’s been challenging for the industry to identify an affordable and yet highly reliable solution that provides high power, deep-water, long length subsea power cables capable of continuously flexing. The entry of new dielectrics for higher alternating electrical stress means there are now solutions for these technologically complex and incompatible demands. However, both direct current (DC) and alternating current (AC) systems have benefits and limitations when used for offshore power systems.

DC systems offer a proven solution to transmit high power over long distances between two points. Yet, DC systems are neither ideal for multi-node topologies nor for end-to-end connection, especially when including conversion of mechanical energy into electrical energy (generation), switching, connectors, protection and final conversion of electrical energy back into mechanical work (eg motors). AC systems offer the possibility of easy and efficient conversion and delivery using the most appropriate voltage across each selection of the network, from the generation through transmission, distribution and control, all the way through to the voltage needed by the motors and other loads at the far end.

This paper will significantly advance research and development efforts in dynamic subsea power cable technology and help progress offshore renewable energy technologies by championing the consideration of system needs before cable design. It discusses the benefits and limitations of alternative cable designs for subsea power links, supported by results from sample and full scale testing of a 72 kV subsea cable design, using concepts suitable for dynamic application. The International Council on Large Electrical Systems (CIGRE) and the International Electrotechnical Commission (IEC) are considering creating standards and this paper proposes a basis for this.
Guidance for Grouted Sleeves in Repair of Offshore Installations
Authors: Alwis N. C. , Dier A. F.
Published: April 2016

This paper provides new guidance on the use of unstressed grouted sleeves in strengthening/ modification/repair (SMR) applications. Presently there is no guidance for the slip capacity of grouted split sleeves having longitudinal bolted flanges, and the available guidance for continuous sleeves (as used in pile-sleeve connections) requires modification to make it applicable for split sleeves. The investigations detailed herein encompass the effects of both axial loading sense (tension or compression) and connection details (weld beaded or plain pipe).

It is necessary, when examining the slip capacity of grouted components, to use test data. A database of continuous and split sleeve test results was therefore compiled, verified and subjected to screening procedures. Available codified provisions for pile-sleeve connections have been checked against the database, and shortcomings have been exposed for extension to SMR applications. The screened database was then interrogated further and enhanced guidance provisions were derived to address the shortcomings, in particular for split sleeve pipe connections.

The results confirm that the latest existing guidance for slip capacity of pile/sleeve connections is suitable for such components with a caveat on plain pipe connections under tension loading. For continuous grouted sleeves in SMR situations, the same guidance can be used. For split sleeves, the reduced hoop stiffness due to the presence of longitudinal bolted flanges usually leads to lower slip capacities than equivalent continuous sleeve specimens. New guidance is presented in this paper to cover such connections.
The Prediction of Fretting Fatigue in the Pressure Armours of Dynamic Flexible Pipes
Authors: O'Halloran Sinéad , Harte Annette , Connaire Adrian , Leen Sean
Published: April 2016

This paper presents a combined experimental and computational framework for the design of flexible marine risers against fretting and fatigue. The framework is based on: (i) a suite of laboratory experimental methods for fretting and fatigue tests, and (ii) a global-local methodology for flexible riser analysis including dynamics and frictional contact mechanics. The effect of coefficient of friction on the predicted substrate stress distributions and fatigue life of the nub-groove region of flexibles has been investigated. It is shown that coefficient of friction has a significant effect on predicted trailing-edge tensile stresses in the pressure armour layer and, hence on fretting crack initiation in risers. The framework should assist in the design of pressure armour layers in flexible marine risers against fretting wear and fatigue.
Can Teamwork Enhance Safety?
Authors: Salas E. , Iwig C.
Published: April 2016

Teams today often integrate the unique expertise of members in order to achieve performance and safety goals not possible by individuals alone, while facing challenges of operating in complex, diverse, and dynamic environments. However, simply relying on team member's expertise is not enough to produce effective teams. The science of team effectiveness has much to offer in regards to our understanding of developing and maintaining effective teamwork and safe behaviors, cognitions and attitudes in complex situations. Drawing upon the current state of the science, we provide an organizing heuristic of critical considerations that should be addressed by those involved in the use of expert teams to enable team success. We further offer scientifically driven guidance regarding ways in which teams can enhance safety based on these considerations. Specifically, the 7 C's synthesize the extant literature on effective teams to help guide organizations in diagnosing and developing teams in environments where performance reliability is paramount. The components of teamwork within this framework emphasize the role of six key team processes as well as one influencing condition. Taken together, these six characteristics of effective teamwork and their influencing conditions are used for practical guidance that will improve safety through teamwork. They essentially allow people to act as individuals, each with their own specialty and talent, while simultaneously enticing them to act cohesively to identify and close potential gaps and risky behavior.
Analysis of the Axial Dynamic Behavior During Installation of Surface Casing in Deep Water Well Construction
Authors: Batista L. G. , Miura K. , Ikeda I. , Mendes J. R.
Published: April 2016

Well construction in increasingly water depths makes harder to design, manufacture and install surface casings to support loads imposed on them. In addition to the static loads, that designers are accustomed, dynamic loads are present in surface casing due to rig movement caused by sea waves. In recent history, there are some cases of unexpected break off or disconnection at the top while running surface casing.

The objective of this work is to model and analyze the axial dynamic behavior and loads generated by the movement of the tubular element system during installation of surface casing in water depths up to 3,000 meters and casings up to 1,500 meters. The idea is to verify if this dynamic behavior compromises the surface casing or the drill pipe used, leading to failure.

To achieve this goal, an analytical model is obtained for the equations of motion governing the tubular element system while running surface casing. From the solution of the equations obtained, several simulations are made in various scenarios to support the conclusions regarding the behavior and the consequences that these movements can cause are predicted.

Although this study uses some equations and modeling already published, the modeling of the boundary condition on the float shoe and the application of models and analysis of surface casing axial dynamic behavior are unprecedented.
Seawater De-Oxygenation: Development of a Compact Technology
Authors: Knox-Holmes Brent , Olmi Claudio , Morse Scott , Caires Luis , Weston Rob
Published: April 2016

To avoid corrosion in water injection tubing, it is necessary to remove oxygen from the source water. Traditional processing equipment has included vacuum and gas-strip de-aeration. Cameron has developed a Compact De-Oxygenation System ("CDX™") technology as a reduced height, light weight alternative. The system injects and dissolves hydrogen into the oxygen rich feed-water before it passes over a catalyst bed, where the hydrogen and oxygen react to produce water and a deoxygenated stream of seawater.

The process has been successfully demonstrated at Galveston, Tx. A 25m3/h demonstration plant was run on high total suspended solids seawater over a period of 6 months. Outlet dissolved oxygen concentrations were in the order of 2.5µg/l (ppb).

The performance of key components of the system is described, including: ultrafiltration membrane pre-treatment under extreme solids loading, the hydrogen generator, mixers and catalytic reactor.

Compared with alternative de-aeration systems, the system offers significant benefits including reduced height, compact packaging, elimination of oxygen without the use of chemicals and pressurized operation.

The paper focuses on the demonstration plant build and testing. Lessons learned throughout the execution of this medium horizon project are presented.

The system is being offered commercially and will be integral to the new designs of water injection system required for future project developments and retrofits.
Modify Methods, Behaviors, and Relationships to Reduce Equipment Costs
Authors: Kendig Bryan , Wodehouse Jim
Published: April 2016

This paper describes opportunities to achieve cost savings relative to purchasing oil & gas production equipment and services in the offshore major project sector. Examples are provided from the perspective of an engineering, procurement, construction, installation & operating (EPCIO) contractor within the Floating, Production, Storage, and Offloading vessel industry (FPSO), however, the challenges and the recommendations equally apply to other offshore structures, including Spars, TLPs, and semi-submersible platforms. The examples provided focus on subjects related to vendor relationships, standardization, technology development, quality, and stakeholder communications.

This paper provides practical recommendations, based upon past experience, in order that organizations may maximize cost reductions on future projects. A novel aspect of this paper is the discussion related to relationships and behaviors (interpersonal communications / actions that will enable a desired cost reduction).
Cement Strength Retrogression Issues in Offshore Deep Water Applications - Do We Know Enough for Safe Cementing?
Authors: Reddy B. R. , Zhang Jilin , Ellis Michael
Published: April 2016

Strength retrogression of set Portland cement at elevated temperatures, for example at temperatures greater than about 230°F, has been known for many years, and is believed to be due to the formation of a variety of crystalline phases at the expense of amorphous calcium silicate hydrate phase. Ground quartz silica is typically added to prevent the strength retrogression. Calcium hydroxide that is generated from cement hydration reacts with silica in pozzolanic reactions to generate amorphous calcium silicate hydrate. It appears from the literature search that there is no consensus as to how much silica is needed to effectively prevent strength retrogression. The amount of silica proposed as sufficient varies from the generally accepted value of 35% by weight of cement to more than 60%. In offshore situations, the problem is more complicated due to the high content of salts present in sea water. The chloride content of seawater has the potential to form crystalline phases, for example Friedel’s salt. The effects of seawater on the required amounts of silica flour for prevention of strength retrogression have not been explored. The objective of this study is to identify the optimized amounts of silica required for a given application temperature in both fresh water and sea water, and search for correlations between macroscopic strength related-properties and molecular level structural features. It is hoped that the information and knowledge will be useful in designing cement slurries for any offshore hot zones.

As part of this study, cement formulations containing different amounts of silica were tested in both fresh and sea water in the 250-400°F range using Ultrasonic Cement Analyzer (UCA). The strength development/retrogression patterns were observed. The cured samples were analyzed by X-ray diffraction studies. In these studies, cement to water ratio is maintained constant to ensure similar hydration rates, and the densities were allowed to vary based on the amount of silica added.

The results clearly indicate that the amount of silica needed to prevent strength retrogression depends on temperature. Highly intriguing strength development patterns, dependent on temperature and the amounts of silica, were observed prior to stabilization at ultimate strengths. Implications of such patterns on well construction strategies are discussed, and molecular level clues from X-ray studies for such patterns are pursued.
Integration of Human Factors into Safety and Environmental Management Systems
Authors: Ciavarelli A.
Published: April 2016

This paper addresses human performance risk mitigation strategies for incorporation into a Safety and Environmental Management System (SEMS). A framework is provided that identifies human factors considerations and evaluation criteria needed for successful integration of Human Factors into a company's SEMS. A methodology is presented for assessing safety culture and the effectiveness of SEMS implementation. Results from employee surveys, taken across various high-risk industries, will be presented. The survey findings illustrate the common difficulties encountered in establishing and maintaining a strong safety culture and the challenges in achieving an effective SEMS.

Successful integration of Human Factors in SEMS for the Oil and Gas Industry can reduce the risks of accidents and manmade disasters, such as the Macondo Well blowout.

Integrating Human Factors into an SEMS might also improve operational efficiency and effectiveness, because Human Factors considers all levels of performance improvement, the individual worker, the work crew (team), and management. Optimum performance by all employees is necessary in order to attain a high level of organizational reliability.

These are some components of Human Factors that contribute to improved safety performance and might help to prevent human error accidents and organizational failures: Clear specification of personnel qualification standards and required knowledge and skill competencies for both workers and supervisors.Utilization of advanced simulation training for individuals and teams.Improved collection, analysis, and display of safety critical well test, and other operational data, with better human – interface technology, improved operational procedures, and continuous technical training.Identifying critical Human Factors hazards and risk mitigation procedures for inclusion in the overall Safety Environment Management Systems.Safety training for line supervisors to include human performance and, communication and risk decision- making limitations and High Reliability Organization – HRO – Culture management principles.Routine assessment of Safety Climate and Culture based on HRO principles – to include valid metrics, benchmarking and desired norms.

These factors are critical components for an effective SEMS - that if missing, or poorly implemented, can serve as the roots of accidents and manmade disasters like Macondo. They are also key areas of assessment that the author has used across industries to evaluate the strength of safety culture and to judge the effectiveness of a successful integration of Human Factors into a company's SEMS. This methodology and lessons learned from the application of these methods can and should be considered for use in the oil and gas industry for achieving a successful implementation of SEMS.
Contribution of Sampling-While-Drilling Technology to Incremental Reserves, Adding Value to Field Knowledge, Avoiding Multiple Drill Stem Tests and Saving Rig Days - A Case Study From the TGT Field, Vietnam
Authors: Phuoc Bui Huu , Hardikar Nikhil , Pragt Jos , Galvan-Sanchez Francisco , Tran Pei-Chea
Published: April 2016

Sampling-while-drilling technology has quickly evolved into an established service and has been used in varied scenarios with object-oriented applications. This case study presents the application of fluid analysis and sampling while drilling a development well in the Te Giac Trang (TGT) field of Vietnam. The application of this technology contributed to accruing reserves, provided a deeper understanding of the production area, and avoided further drillstem testing, thereby saving numerous rig days.

The principal challenge was to reduce the uncertainty in reservoir fluid type that remained after drillstem testing results from the exploration phase. The objectives included confirming the formation fluid type in two reservoir units, formation pressure regime and determining the pressure communication with the production area. The aim was also to avoid three more planned drillstem tests. Timing was critical, so two runs were planned strategically after the hole section was drilled.

The first run performed was formation pressure testing with fluid identification and sampling from 11 prioritized depth stations. The mobility ranged between 29.3 and 128.1 mD/cP. The cleanup duration and volume ranged between 1 hour 14 minutes with 70.0 litres and 3 hours 7 minutes with 154.7 litres pumped respectively for the high- and low-mobility depth stations. A total of 1009.8 litres were pumped in 23.6 hours. The samples were sent immediately to the PVT laboratory for quick analysis. Despite the high levels of invasion expected during the cleanup and sampling operations, the contamination level was less than 10%; mostly between 4% and 8%; the lowest was 3%. Ten single-phase fluid samples were collected, out of which seven were oil and three were gas. As a result of the fast turnaround of the sampling results from the first run, the subsequent run performed was pressure testing only, with 61 depth stations. With a maximum overbalance of 1,381 psia (9,522 kPa) from both wiper trip runs, the sampling-while-drilling application provided excellent pressure repeatability with 100% sealing efficiency and representative formation pressure, mobility and fluid data.

The planning of sequential runs with sampling to confirm fluid type followed by a run for additional pressure tests enabled the sampling-while-drilling technology to identify incremental reserves and avoid multiple drillstem tests, saving an estimated 35 rig days. The acquired pressure testing data added valuable information to the pressure communication dynamics between reservoir layers of the well and adjacent producing area of the field.
DCNS' Solutions for Deep Sea Environmentally Friendly Activities
Authors: Demoor Damien
Published: April 2016

The exploitation of marine resources has enjoyed renewed interest with a completely new sector, that of the Deep Sea Mining of mineral resources in the seabed, that is now gaining momentum. Nevertheless, the significant environmental constraints represent a challenge for initiating these new activities, whether this is in terms of the knowledge of the concerned ecosystems or in terms of monitoring and minimizing the impact of these new activities. In the meantime, these prerequisites are becoming increasingly applicable to the Oil and Gas sector, at least in areas adjacent to countries that are sensitive to sustainable development, with increasingly prevalent regulations. This paper presents 2 technologies that aim to respond to the expectations of the stakeholders in this area. The first consists of the real-time monitoring of installations/operations and their impact on the environment using the most modern underwater technologies. The second consists of a membrane allowing the confinement of an area, the reduction of the emission of particles in suspension, noise reduction and thermal insulation.
New Grades of High Strength Steel for Offshore Mooring Chains: R5S (1100MPa) and R6 (1200 MPa)
Authors: Albisu Beatriz , Salado Itziar , Arredondo Alberto , Bilbao Daniel , Abrisketa Mikel , Arana Jose Luis , Idoyaga Zuriñe
Published: April 2016

This paper is focused on the definition of two new grades of high strength steel for offshore mooring chains providing increased strength and reduced weight for a given size.

The new grades are identified as:

R5S, with an ultimate tensile strength of 1100 MPa.

R6, with an ultimate tensile strength of 1200 MPa.

 

Both grades should be considered as new solutions for those offshore applications in which the mooring has shown to be risky, technologically challenging and capital intensive, such as deepwater exploration and production, wind power or locations where in-service metocean conditions could exceed the design ones.

Recognising these challenges as opportunities to develop an appropriate solution, the grades R5S and R6 have been designed, used for chain manufacturing and characterized with standard mechanical tests, fracture mechanics, fatigue and hydrogen embrittlement, so as to ensure their suitability for those offshore opportunities.
Pipeline Leak and Impact Detection System - PipeLIDS - Monitoring Product Dedicated to Onshore Pipelines
Authors: Mabily Daniel , Lehning Virginie
Published: April 2016

Onshore pipelines may be subjected to third party damage (civil works), corrosion leaks, mechanical issues (valve or pumps failures), land movements or (in extreme cases) theft of the product. These threats may lead to leaks or even more dramatic explosions. The impact on human life and the environment can be significant. The pipeline operator's public image can be damaged with non- negligible economic or political consequences.

PipeLIDS has been developed to minimize the consequences of leaks from onshore pipelines. It uses acoustic technology for detection of noise generated by impacts or leaks. This noise propagates in both directions over long distances inside the pipe. Intrusive acoustic sensors are installed regularly on the pipeline (every ten kilometers) to detect this noise. Each sensor is connected to an intelligent beacon with GPS synchronization. By measuring the sound wave's amplitude and phase time shift and analyzing the acoustic signature, PipeLIDS detects the origin and location of the event and raises an alarm.

This paper presents latest technical improvements implemented on the PipeLIDS as installed on the latest SPSE Fos-sur-Mer (France) diesel pipeline for permanent survey. Acoustic sensors have been redesigned for better reliability. Software was reviewed and updated to give more efficient data processing, detecting and locating any accidental events within few minutes while being able to eliminate false alarms. Finally, very good performances of the system is demonstrated as well as its simplicity in terms of installation.