bluuebunny/crossref_metadata_2025 huggingface dataset:
Water Injection in Deepwater, Over-Pressured Turbidites in the Gulf of Mexico: Past, Present, and Future
Authors: Duan Shengkai , Lach Joseph R , Beadall Kris K , Li Xin
Published: May 2013

Waterflooding can supply additional reservoir energy for producing substantial quantities of oil trapped due to limited displacement drive and poor sweep efficiency. However, water injection is not commonly used in the deepwater Gulf of Mexico (DW GoM) due to good primary recovery, drilling cost and facility limitations. In over 80 fields and 450 reservoirs, water injection program has been implemented in only 18 reservoirs in 13 fields, or less than 5% of potential waterflooding candidates.

DW GoM mid-Miocene reservoirs are characterized by sparse well counts, over-pressured, and generally good rock and fluid properties. Rock compaction and moderate aquifer influx often provide moderate to good natural drive energy and oil recovery. Primary oil recovery averages 32% with the 80% confidence range between 16% and 48%. However, Paleogene reservoirs are characterized by deeper depth, high pressure, high temperature, complex geology, and rock and fluid properties. Estimated recoverable oil is only 10% of OOIP assuming primary production and limited natural drive energy. Water injection programs will be difficult to execute in tight, abnormally-pressured Paleogene reservoirs. Waterflooding of deepwater turbidites has accumulated many lessons and learns now, and a comprehensive understanding of the influence of depositional environment and injection into over-pressured, highly compacting rocks is necessary. This paper is a detailed examination of Pleistocene-to-Upper Miocene age turbidite reservoirs in the DW GoM under water injection. Issues on waterflooding these deepwater plays were reviewed in the context of geological setting and depositional environment. Despite many drawbacks that tend to oppose the implementation of a waterflooding in Paleogene reservoirs, this paper still proves that they are candidates for water injection programs under the rules of good production practice. Moderate oil recovery is suggested in highly compacting reservoirs with supplemental injection drive. Overall, waterflooding strategies have proven to be highly effective in achieving good incremental oil recovery from the deepwater Gulf of Mexico reservoirs.
Modular Tlp Structure for Offshore Wind Turbines
Authors: Dahlhaus Frank , Grossmann Jochen
Published: May 2013

The Offshore Wind Resources in deep water, but also the currently experienced issues with conventional foundations, are driving the solution requirements for new offshore wind power platforms. The latest monitoring results of German offshore wind farms show the challenges the industry is facing. Ecological impacts as well as foundation technology issues are forcing the sector to look for alternatives.

The paper will introduce a technology of a floating TLP-structure in open relief design with a specific configuration of mooring line system used for wind turbines, suited for water depths greater than 30 meters. The unique aspect of the GICON TLP is its modular framework structure which allows buoyancy and load transfer functions to be decoupled from each other and instead be applied to the specific structural elements. The overall structural behavior is characterized by lattice structures in the connection node of column and boom and the entire rigger area. The load and stress forces on the structure are clearly defined and unwanted or double loads as well as overloads can be prevented. The structure is designed to handle both the tension forces from the mooring system as well as the buoyant force. The total buoyant force can optionally be adjusted via additional buoyancy elements of variable shapes and dimensions, preferably in the form of spherical or circular cylindrical hollow bodies. These can be set at various locations across the truss structure to adapt to different deployment site requirements. In numerical simulations the dynamic behavior of the TLP under linked hydrodynamic and aerodynamic loading is taken into account also regarding different geometric configurations of the mooring line system and various types of anchorage systems at the sea floor. Using characteristic Campbell-diagrams structural stiffness of each component is optimized aiming at a soft-stiff design of the TLP-structure. Eigenfrequencies are calculated for various water depths and different geometric conditions of the mooring system. Numerical modeling validation is confirmed by tank tests. Data and video from the tank tests will be shared a part of the presentation. GICON researchers plan to install a full-scale pilot plant in the Baltic Sea in 2013.
Pipe-in-Pipe: Thermal Management for Effective Flow Assurance
Authors: Dixon Mark
Published: May 2013

Introduction

Deepwater technology accelerated rapidly about 10 years ago, when exploration moved from shallow to deep and ultra-deep offshore region. For such developments flowline insulation is increasingly applied and technology advancement has been the key driver for the subsea field developments in deepwater. This often creates situations where certain technical products dictate the system concept and configuration, leading to costly solutions that are not always effective or safe.

In this paper a systems approach is applied to review Pipe-in-Pipe (PiP) types and capabilities, as well as their impact on the flow across the entire subsea field development and the asset lifecycle.

Systems engineering is the key method to achieve integrated field development planning and execution. It prioritises the system functionality, allowing translation of all the technical factors into a structured field development process to provide operators, who are responsible for setting up subsea architecture, with the necessary decision-making framework for the project. The specific field development issues usually include cost-technical risk optimisation, making the right choices of available technology, availability of the appropriate infrastructure with levels of local access, content and capability as well as flexibility for parameters and field development stage change in the future - with minimal disruption. By mapping the inter-dependence of variables, seeing how the decisions and actions taken at each stage affect subsequent stages, systems engineering enables evaluation of design trade-offs via their impact on key system goals and operational targets.

A Subsea System has different content levels. On the vertical ‘seabed-to-processing’ axis it consists of: Host facility, SURF infrastructure (wherein the PiP technology lies) and SPS system. Systems framework helps to balance their competing requirements to achieve operational stability of the overall project.
Development of Offshore Wind Recommended Practice for US Waters
Authors: Musial Walt David , Sheppard Robert Edward , Dolan Daniel , Naughton Brian
Published: May 2013

The American Wind Energy Association (AWEA), as a standards development organization, sponsored the development of recommended practices (RP) for offshore wind turbine facilities and published its RP report in 2012. The challenges faced by the emerging offshore wind energy industry parallel many of the challenges that were faced by the offshore oil and gas industry in its infancy. These challenges are documented and addressed in the development of the AWEA RP and are described in this paper. The paper discusses how the more mature American Petroleum Institute oil and gas standards were interfaced with International Electrotechnical Commission and other wind turbine and offshore industry standards to provide guidance for reliable engineering design practices of these mechanically dynamic, fatigue-driven offshore wind energy systems. Uncertainties requiring further validation and analysis are also described.

Background

There are a number of offshore wind energy projects at various stages of development for both the federal and state waters of the United States, but none have started construction. The National Renewable Energy Laboratory estimates that U.S. coastal waters have approximately 4,000 GW of gross offshore wind energy resources if all the resources over the waters from the shore out to 50 nautical miles out are included (Musial 2010). However, development of offshore wind resources in U.S. waters is in its nascent stages, and several barriers to deployment must be overcome before offshore wind energy can be successfully integrated into the electric energy generation mix at a large scale. Some of the barriers include immature infrastructure and supply chain, the need for further technology optimization, reliability concerns, and lack of uniform regulatory guidance on the design, installation, and operation of these facilities. The focus of this paper is to describe some of the industry efforts that have been devoted to providing guidance to inform developers, designers, and regulators on the application and applicability of existing standards.
Implementing a Deepwater Pipeline Management System
Authors: Gueveneux Herve , Samosir Laufer Theo Manongtong , Lechon Alain , Popineau Dominique
Published: May 2013

As an operator, TOTAL has experienced significant deepwater maintenance and repair works activities such as Cut-out and replacement of a damage section of water injection line, Replacement of Flexible riser, Replacement of Anchor line and its Pile, Repair of Umbilical Termination Head etc.

There are few deepwater pipeline operators with experience of pipeline repair, which need to be carried out with significant preparation time for intervention tools, including engineering and testing of the tools.

Deepwater operations (including IMR) require a completely different paradigm to conventional offshore operations, specialized competencies, contractors and tools. The pipeline repair activities mastered in conventional offshore operations are becoming difficult tasks in deep water as they have to be done remotely whilst the pipelines characteristics are quite different. Furthermore, there are many important challenges ahead still to overcome such as repair of pipe-in-pipe, of production bundle, of flowline with H2S content, of flowline connection etc. which mean another challenge for research and development to find proper tools and methodologies for deepwater intervention.

This paper describes the strategy developed and implemented on deepwater pipeline intervention, based on a deepwater operational experience built over a decade. It also presents the experiences on dealing with integrity issues and how to move forward in existing operations and preparing for the future developments.

Once the proper technologies are acquired, a pipeline repair systemshould be established as part of operational management philosophy.

An Operator involved in the development of deepwater operations should seriously take into consideration from the design stage:–The way to perform the condition monitoring of the pipeline and its appurtenances–The way to repair or replace the pipeline section should there be any failure during production.

Being well prepared to face unexpected failures in the deepwater pipeline network would benefit him to:–Maintain the level of integrity of the deepwater pipeline network–Minimize production loss and shortfall–Minimize intervention costs–Maintain the Operator image with international media and National Oil CompanyIntroduction

TOTAL operates in deepwater since 2000 and until now there have been six deepwater fields put into production and several more are under development.
Predicting Subsalt Pore Pressure with Vp/Vs
Authors: Saleh Saad , Williams Ken , Rizvi AiJaz
Published: May 2013

This paper presents the results of an investigation of shear and compressional velocities and their ratios for pore-pressure prediction in a subsalt environment. In this work, we introduced the state of the art in the analysis of acoustic methods—compressional velocity (Vp), shear velocity (Vs), and Vp/Vs ratio—for pore-pressure estimation. Because industry best practices of using shear velocity and Vp/Vs ratio are still being developed, we evaluated a number of existing techniques and methods, advanced new approaches, and developed the necessary database of modeling results.

This database contains data gathered from 17 subsalt wells and includes definitive pore pressure and effective stress directly pertinent to the subsalt sediments. Velocity and resistivity data were then crossplotted against effective stress to define the correlation among these variables. Based on several forms of published velocity effective-stress relationships, we worked to calibrate these relationships and to simplify some of these formulations to get a tractable direct solution for pore pressure.

To validate these relationships, we selected certain other relationships and performed tests, which resulted in varying degrees of success. These tests represent 17 wells that penetrated salt. Ten of these 17 wells have good pore-pressure control data, which is a good pool of cases for a screening analysis from which we can derive lessons learned for future improvements.

Based on these results, we drew the following conclusions:The unconventional pore-pressure analysis approach of using Vp, Vs, and Vp/Vs with a modified Eaton method (1975) was successful. The unconventional analysis of Vp produces more consistent results than Vs-based pore-pressure analysis. Further tuning is required to develop area-specific model parameters.The rock-physics-based pore-pressure transform derived directly from the simplified and calibrated Eberhart-Phillips equation (1989) showed better performance than the modified Eaton approach. This approach will eliminate the guesswork for defining normal-compaction trend for velocity.

This work accomplished the following benchmarks:Development of velocity effective-stress transforms that are tailored for the Gulf of Mexico subsalt sediments.Simplified the process of pore-pressure prediction using Vp, Vs and their ratios utilizing a universal rock-physics-based normal-compaction trend.
Near-Bottom Acoustical Detection of Bubble Streams Emanating From Natural Seafloor Seeps in the Gulf of Mexico
Authors: de Moustier Christian , Zabal Xavier , Boelmann Jan , Kraft Barbara , Zielinski Oliver , Fox Peter
Published: May 2013

A method is described for acoustical detection of bubble streams in the water column while conducting swath bathymetry surveys at 20 m altitude with a deep-diving ROV. Such bubble streams emanate from natural seafloor seeps. The same acoustical tools are then used to measure the flow rates of the detected bubble streams. The goals of this work are to quantify the volume flux emanating from natural seeps found on salt domes and mud volcanoes in the Gulf of Mexico. A combination of acoustical and optical tools was used for this purpose. The sonar used for this work was a forward-looking multibeam echo-sounder operating at 500 kHz. In detection mode, the sonar axis was tilted about 30º above horizontal to avoid ensonifying the bottom. In this mode, small bubble streams (individual bubbles rising in a column about 0.2 m in diameter) were detectable at ranges in excess of 50 m. Once a bubble stream was detected, the ROV would be navigated towards it until visual contact was established with video cameras installed aboard the ROV. Then, the sonar head was tilted upward and acoustic data were collected in imaging modes and in Doppler modes to track the ascent of bubbles in the water column. The main results of this work are bubble flow rates about 0.2 m/s, and bubble streams of a much smaller extent than anticipated from independent detections with a shipboard echo-sounder.

Introduction

The Mississippi Canyon protraction area (NH16-10) (BOEM, 2000) on the outer continental shelf of the northeastern Gulf of Mexico is an active oil exploration and extraction area associated with numerous salt domes and mud volcanoes. Natural hydrocarbon seeps found on these domes contribute oil and gas to the marine environment. It is estimated that 95% of the total offshore oil input into the Gulf of Mexico is due to natural seeps (OSB, 2003). However, the episodic release rates of these seeps make them difficult to detect. Shipboard acoustical methods have successfully detected such seeps when they include bubble streams emanating from the seafloor (e.g. Greinert et al., 2006; NOAA, 2011). When investigating known seeps with near-bottom video survey tools, the seeps are difficult to find because bubble streams are small and the field of view of the cameras is limited to a few meters. The objectives of the work presented here were to use acoustical methods to detect and measure the flow rates of natural seafloor seeps during near-bottom surveys at three sites in the northeastern Gulf of Mexico: Biloxi Dome, Dauphin Dome and Mars Mud Volcano.
Drilling and Completing Cascade and Chinook Wells: A Design and Execution Case History
Authors: Gama Fernando , de Moraes Flavio Dias , Ogier Kenneth Scott , Moreira Oswaldo , Rebelo Mauricio Pestana , Shipley Jonathan A. , Haddad Ziad A
Published: May 2013

The paper is based on work performed during the design, implementation and operation of the Cascade and Chinook Field Development Project in ultra-deep water in the Gulf of Mexico. It describes the basis of design for the drilling and completion of the wells, new technology selection criteria, risk and cost mitigation plans applied during the well operations, ultra-high pressure perforating of an interval longer than 700 ft, application of the first Single-Trip Multi-Zone Frac Pack System (3 zones) in wells deeper than 27,000 ft MD, and the unique fracturing design approach used to deliver multiple fractures across 1200 ft of reservoir thickness. This case history paper will describe the pre-qualification work done with all critical systems and details of the well construction operations during the drilling and completion of the wells. The information provided will be useful for Operators to identify the technologies that are most suited for application in deep wells. It will also serve as a starting point for the design and construction of wells for other operators developing projects in the Lower Tertiary play, which is a key exploratory frontier in the U.S. Gulf of Mexico (USGoM). More than 12 discoveries have been made in the Lower Tertiary, with potential recoverable reserves of several billion barrels of oil. The results and conclusions presented in this paper are related to the feasibility and benefits of using new technology and prototype equipment in the Lower Tertiary environment. Field data from critical well operations will be included.

The technical contributions of the work presented in this paper are as follows: pushing the technical limits of Single-Trip Multi-Zone frac-pack systems to depths over 27,000 ft using high (>30 bpm) fracture rates and high strength proppants; enhancing the knowledge gained from ultra-high pressure (>20,000 psi) tubing conveyed perforating systems; and presenting a well design criteria suitable for high drawdown (>12,000 psi) production operations.

Introduction

The Cascade and Chinook (C&C) development plan in the Gulf of Mexico is one of the most technologically challenging and complex projects implemented by Petrobras. This project uses the first Floating Production Storage and Offloading vessel (FPSO) in operation in U.S. waters, at a water depth of 8200 ft. The C&C subsea infrastructure considers the use of subsea manifolds, rigid flowlines, pipe-in-pipe pipelines, and Free Standing Hybrid Risers (FSHR). Details about the subsea infrastructure and the FPSO are discussed in greater detail by Porciuncula et al. (2010) and Corte et al. (2010).
The Gulf of Mexico Subsalt Wells Atlas: A Comprehensive Review and Lessons Learned
Authors: Williams Ken , Saleh Saad T , Rizvi AiJaz
Published: May 2013

A joint-industry project (JIP) acquired, analyzed, and documented more than 100 subsalt wells in the Gulf of Mexico (GoM), from shelf to deepwater (2007-2009). The result of this unique and major study culminated in an unprecedented comprehensive database, which includes geophysical, petrophysical, and drilling data. This database is being used for several objectives: developing best drilling practices above, within, and below salt, building salt geologic models, and developing best practices for pore-pressure estimation below salt.

An analysis summary has been written for each well, documenting pore and fracture pressure gradients, drilling data, drilling history, and salt geologic modeling. These summaries have been compiled into a five-volume subsalt well atlas, which contains a treasure trove of well data, lessons learned, and analysis. The atlas classifies wells according to their geographic location (Continental Shelf, Eastern, Central, and Western) and salt provinces. The atlas provides a quick reference analog resource for use by professionals drilling subsalt wells.

This paper provides key insights into the information that is presented in the subsalt wells atlas, highlights observations on drilling windows, salt tectonics, salt geometry, and petrophysics of each salt province/area, and provides well examples from each. For example, pore pressure is highly variable in the subsalt wells in this study, with a range from 9.0 to 18.0 ppg. In many of these wells, the pore pressure approached the overburden gradient, leaving a very small drilling margin. The atlas attempts to highlight the challenges faced in drilling these wells that, in many cases, led to well termination short of the target. The project integrated geology, geosciences, and well-construction information across a vast and complex GoM area, for a variety of wells, from shelf to deepwater.

Introduction

This paper attempts to present a synopsis of the Gulf of Mexico subsalt wells atlas, which was developed as a part of the deliverable on a JIP (2007-2009) to study pore-pressure prediction (as a major focus among other objectives) in the Gulf of Mexico (GoM) subsalt sediments. The atlas with its five printed volumes (over 700 pages), along with a digital library, represents an unprecedented inventory of drilling, geology, and petrophysical database for subsalt wells in the GoM. A team of highly experienced professionals from different disciplines (geology, drilling, and pore-pressure engineers) had participated in this project. An industry advisory group guided the project progress and contributed through many progress meeting and forums. The highlights in this paper can only be an outline of selected topics covered by the atlas.
Water Management for EOR Applications - Sourcing, Treating, Reuse and Recycle
Authors: Llano Valentina , Henthorne Lisa , Walsh John
Published: May 2013

The growing popularity of water-based Enhanced Oil Recovery (EOR) techniques, such as Low Salinity Injection (LSI), Chemical EOR (CEOR), and steam-flooding, impacts the water footprint of the oil and gas industry. It also affects the water treatment industry by creating new opportunities as a function of the requirements of equipment and systems in EOR projects. In some cases, the needed technologies have little to no history of application in the upstream oil and gas industry, therefore impacting EOR project budgets and schedules. These issues become particularly acute in offshore applications that are generally limited by footprint and weight, thereby further reducing suitable water treatment options. The issues are further confounded by the lack of communication between oil companies on equipment successes and failures in these new applications. EOR projects are often kept as low profile, particularly by smaller oil companies, to strengthen competitive advantages in the marketplace.

One of the best treatment options for the environment is the reuse of produced water for re-injection in EOR applications. This is particularly attractive in CEOR where residual polymer and surfactant may deem the produced water unacceptable for discharge. But injection additives may stabilize emulsions and render the produced water and oil mixture challenging to separate. Ideally, water treatment technologies are used that both enable good separation and maximize potential reuse of produced water.

As a first step in disseminating the current body of knowledge of water usage and treatment in EOR applications, a survey was conducted in 2012 of water-based EOR projects to ascertain their water source and background information on the water treatment technologies employed. The survey was co-sponsored by the Produced Water Society. Specific information on the source water salinity and temperature was obtained, in addition to the type of EOR used, the project location, and details of the existing treatment system(s). The survey results were then augmented with exhaustive literature searches of both full-scale EOR applications and emerging technology solutions currently being piloted.

This paper describes the survey results which detail water-based data from more than fifty EOR projects around the world, along with a critique of the emerging technologies being piloted in global EOR field sites.
Increasing the Accuracy of Marine CSEM Survey Planning and Data Interpretation Using Novel 3D TTI Anisotropic Resistivity Modeling
Authors: Frenkel Michael
Published: May 2013

The marine Controlled-Source Electromagnetic (CSEM) method has been evolving into a subsurface resistivity imaging tool for increasingly complex geological settings. It allows recovery of subsurface resistivity, a key hydrocarbon (HC) indicator, using modeling- and inversion-based interpretation of EM data acquired on the seafloor. Application of CSEM can reduce risk and optimize drilling operations, as well as improve estimates of HC reserves. The CSEM workflow is comprised of feasibility study, survey design, data acquisition, processing, and interpretation. Survey design and data interpretation rely heavily on 3DEM modeling to properly select and plan surveys and recover the 3D subsurface resistivity image.

Currently, simplified 3D Vertical Transverse Isotropic (VTI) resistivity models are applied to simulate EM fields over complex anisotropic subsurface geological structures. This may lead to incorrect assessment of the feasibility of a potential CSEM survey, as well as mispositioning of targets and erroneous assessments of their parameters during interpretation of acquired marine CSEM data. Therefore, there is a need to start using 3D Tilted Transverse Isotropic (TTI) models, which provide a much more accurate description of complex anisotropic resistivity structures than the widely used VTI models.

To perform simulations of TTI models, we use a 3D finite-difference (FD) modeling method that allows simulating arbitrary 3D anisotropic models. We can apply our workflow to build a 3D TTI model or alternatively utilize a 3D resistivity/conductivity volume determined from a geological/resistivity model with each cell or a set of cells described by the 9-component conductivity tensor. Our method provides simultaneous accurate computation of all the components of the EM fields at any number of frequencies and hence offers fast 3D TTI simulation for complex marine CSEM applications.

In this paper, to demonstrate the difference between the TTI and VTI, we used 3D benchmark models with different orientations of the vertical-horizontal background resistivity (Rv, Rh) pair. The TTI effects were assessed using comparisons of simulations for TTI and the corresponding VTI models. The presented 3D modeling results show that ignoring the TTI effect, if it exists, can lead to incorrect conclusions at the feasibility study and data inversion steps of the CSEM workflow. This study makes the case that application of 3D CSEM TTI modeling can improve the reliability of CSEM by increasing the accuracy of survey planning and data interpretation, which, in turn, will accelerate the adoption of marine CSEM technology.
Development of a Real-Time Riser Fatigue Monitoring System
Authors: Saruhashi Tomokazu , Kluk Daniel J , Kyo Masanori , Bhalla Kenneth , Sawada Ikuro , Miyazaki Eigo , McNeill Scot , Yamazaki Yasuyuki
Published: May 2013

As risers are deployed into deeper water, they are subject to increasingly severe environmental loading due to ocean currents and surface weather. Analytical models of these risers often predict premature failure due to the required safety factors and conservative modeling assumptions. As the design boundaries are extended, field measurements become necessary to assess the accuracy and safety margins associated with these models. Additionally, such measurements are expected to play a prominent role as quantitative structural integrity management programs are formalized and mandated.

We have developed a Riser Fatigue Monitoring System (RFMS) to provide field measurements of drilling riser stress and fatigue in real-time. To our knowledge, real-time fatigue monitoring of an entire drilling riser has not been accomplished previously.

The RFMS calculates drilling riser stress states using measurements from accelerometers and angular rate sensors inside Subsea Vibration Data Logger (SVDL) modules installed at strategic locations along the riser length. This method is preferred to resistive or fiber optic strain gauges due to the measurement quality and reliability concerns associated with installing such devices subsea. The SVDL units are connected via fiber optic subsea cabling to a central data acquisition system, located topside.

Data from each SVDL is displayed as it is acquired, and processed with a sophisticated online computer algorithm to synthesize stress estimates along the entire riser length using a database of riser dynamic modes. The estimates are then processed chronologically via rainflow counting, recording fatigue damage accumulated during the deployment. The fatigue estimates are updated at 15-minute intervals, thereby providing actionable information to the drilling crew in real-time. This enables the crew to make informed and timely responses to damaging events such as loop currents, wave action, or improper tensioner settings. Additionally, the accumulated fatigue damage estimates may be tracked on a per-joint basis as the riser joints are rotated among different well sites, thereby aiding decisions regarding the frequency of joint inspection intervals.

Significantly, since the only required online inputs are the dynamic riser response, top tension (TT), and mud weight (MW), fatigue estimates may be calculated without knowledge of the impinging currents or other forcing events (although the fatigue response may be correlated to these data, if available).

We deployed the system at two well sites off the coast of Japan at 1,180- and 1,939-meter water depths. It successfully collected and processed data from August to November 2012, recording a number of riser excitation events (and attending fatigue damage) due to operations, weather, and vortex-induced vibration (VIV) while connected to and disconnected from the wellhead.
Barracuda Subsea Helico-Axial Multiphase Pump Project
Authors: Tosta da Silva Luiz , Carbone Leonardo Chagas , Coelho Eduardo Jose de Jesus , Cerqueira Maxwell Brandao , Kuchpil Cassio , Maia de Souza Carlos Eduardo
Published: May 2013

PETROBRAS, other operators and suppliers have carried out many efforts to make available the subsea multiphase pump technologies. Many of these pumps were installed and are now in operation, including helico-axial pumps. However, until now, these pumping systems were limited to differential pressures lower than 45 bar, which is not attractive to PETROBRAS scenarios, since the gas-lift has similar performance. Thus, PETROBRAS launched a program to qualify, through flow loop tests and field operation, a helico-axial multiphase pump to differential pressures up to 60 bar. The Barracuda field was selected to host the prototype. This paper describes the Barracuda helico-axial multiphase pump, including the design phase, qualification process and operational experience so far, involving: installation, commissioning and operation.

The Barracuda multiphase pump is designed to operate at maximum differential pressure of 70 bar. The other main flow characteristics are: liquid flow rates between 2000 and 3000 m3/day; GVF between 35 and 60%; and viscosity between 15 cP and 20 cP. The pump is installed at a water depth of 1040 meters and distant 10,5 Km from the P-48 production platform. The boosting system is composed by many components, including a flow base, control system, topside equipments, integrated umbilical and subsea motor-pump unit inside the pump module. This boosting system was comissioned in July of 2012 and since then its operational performance has been evaluated.

A description of the main subsystems of the Barracuda Multiphase pump is presented, including their qualification process and FAT tests. In order to evaluate the hydraulic performance of the motor-pump unit, a special flow loop test program was established. The results of this qualification process and the operational experience indicated that this technology is adequate to be applied in other similar applications.

Boosting untreated oil is a field proven solution and is coming to the age. Efforts to develop high differential pressures multiphase pumps will increase its operational envelop, that will enable its use in important scenarios, accelerating the number of applications and increasing the benefits of this important subsea boosting method. The benefits to brown and green fields will be significant, mainly to Campos Basin scenarios.
Riser Concepts for High Motion Vessels in Ultradeep Water
Authors: Head William , Power Thomas L. , Royer Brian
Published: May 2013

The paper addresses early work executed during the research study for RPSEA project 10121–4401–01 Ultra-Deepwater Riser Concepts for High Motion Vessels. The steel catenary riser is the simplest riser configuration but has limitations when attached to a high-motion vessel, such as a conventional semi-submersible or a ship-shape floating, production, storage, and offloading vessel (FPSO), in water depths approaching 10,000 feet. Further challenges are posed by the high-pressure, high-temperature reservoirs that can be encountered at these water depths. Alternate riser arrangements to meet the demands of both ultra-deepwater and high motion vessels are investigated. Production is assumed to be high pressure (20,000 psi SITP), high temperature (350°F), and sour. Configurations include wave shapes and other methods to reduce the coupling between vessel motion and the fatigue-critical riser touchdown zone. The work described in this paper is primarily concerned with static configuration and vessel payload considerations of the various riser material/configuration options.

Introduction

This paper and an anticipated follow-on paper will present the results of a currently active RPSEA study whose objective is to evaluate potential riser concepts for high-motion vessels operating in waters up to 10,000 feet deep in the Gulf of Mexico (GoM). Among the goals of this study are:Identify technology gaps—in particular, those that represent concepts/aspects that appear analytically promising but have yet to be field-proven.Determine feasibility for particular concepts.Identify preferred riser options.

The study scope to be discussed in this first paper includes:Problem framing–Literature search–Identification of candidate systems–Compilation of design basisPreliminary sizingStatic analysis/designIntermediate conclusionsRefinement of options/goals for remaining work

The follow-on paper is anticipated to cover dynamic system analysis (coupled analysis of floater, risers, and buoys), fatigue considerations, final comparison of options, and recommendations for further study.

As is typical for RPSEA studies, a project working group was formed, comprising riser specialists from five oil companies with ultra-deepwater interests. The project working group is responsible for providing guidance to the study in order to insure that its results are valid and useful to the industry at large.
Compact Oxygen Removal for Waterflood Projects
Authors: Brinn Matthew
Published: May 2013

In the oil and gas industry, once primary oil recovery is not an option, water is injected into oil reservoirs to maintain pressure and " push" oil out of the rock crevices within the reservoir to increase oil recovery. This technique is denoted as waterflooding and allows what is referred to as secondary oil recovery. A major cost to the oil industry for this type of process is corrosion of piping in both the downhole tubing as well as the surface production piping. The primary culprit of corrosion is the presence of dissolved gases and chemicals in the waterflood and produced water. Dissolved oxygen (O2), carbon dioxide (CO2), and hydrogen sulfide (H2S) - individually and in combination - contribute to the majority of the corrosion damage, and can be reduced by treatment of process water. The reduction of dissolved oxygen can also have a secondary benefit of reducing microorganism growth, which can obstruct rock crevices and reduce oil recovery.

The traditional technologies that exist in the oil and gas space to reduce dissolved gases in larger volumes of water include chemical treatment, membranes, and contacting towers. The preferred approach of chemical treatment is increasingly expensive and its usage of chemical are being reduced or restricted for regulatory and/or environmental reasons. This paper will look at an alternative approach to water treatment which builds on the rotating packed bed technology which has been in existence for at least four (4) decades.
CFD Modeling of Bubbly, Slug and Annular Flow Regimes in Vertical Pipelines
Authors: Dai Yi , Dakshinammorthy Duraivelan , Agrawal Madhusuden
Published: May 2013

Deepwater production offers many challenges to oil & gas companies. The challenges are mainly due to operations at ultra low temperatures, high pressures, long pipelines and transporting multiphase phase flows. From purely transport point of view, there is clear need to better understand the multiphase flows in these pipelines. The multiphase flows in these pipelines are characterized by flow patterns or regimes that define a particular distribution of liquid and gas volume fraction in the pipeline. Pressure drop and other transport characteristics such as mass and heat transfer are closely related to the flow patterns or regimes. Thus the flow regime prediction is an important and vital step in understanding the multiphase flows. Untill now most of the numerical multiphase models that are used in design also require apriori knowledge of the flow regimes.

Typically flow regime maps are used and these are dimensionless and should be applicable to wide variety of flow scenarios (fluid properties and pipe sizes). However recent experiments have suggested that flow patterns and other parameters are different in small and large pipes. In this paper, we used a CFD based model in understanding and prediction of bubbly flow, slug-flow/intermittent, semi-annular and annular-flow of vertical pipeline. The CFD model uses Eulerian-Eulerian Multifluid VOF approach to model all the flow regimes, as it allows selective use of surface tension and interface sharpening schemes in an Eulerian framework. Gas holdup, pressure drop and flow instabilities will be predicted and compared with available data for different flow regimes. The predicted results shows good agreement with the experimental work and clearly highlight application of CFD modeling to predict the flow regimes and to get better understanding of complex flow behavior in gas-liquid vertical flows.
Today's Top 30 Flow Assurance Technologies: Where Do They Stand?
Authors: Kondapi Phaneendra , Moe Randi
Published: May 2013

The purpose of this paper is to provide conclusions from an extensive evaluation of all known state-of-the art flow assurance methodologies. The various technologies were assessed by maturity level (i.e. embryonic, emerging, matured or aging), applicability, solution type and their effectivity. Effectivity is a function of ease of application, probability of success and cost effectiveness. Within this study, the solutions were classified into thermal, chemical, hardware, operating and software technologies.

Thirty different existing and developing flow assurance technologies were considered for this study with the aim to summarize the current state of technology and identify potential areas for improvement. The selected technologies are regarded as major enhancers and perceived to have a great impact on both cost effectiveness and production.
Top-Down Clustering for Protein Subfamily Identification
Authors: Costa Eduardo P. , Vens Celine , Blockeel Hendrik
Published: May 2013

We propose a novel method for the task of protein subfamily identification; that is, finding subgroups of functionally closely related sequences within a protein family. In line with phylogenomic analysis, the method first builds a hierarchical tree using as input a multiple alignment of the protein sequences, then uses a post-pruning procedure to extract clusters from the tree. Differently from existing methods, it constructs the hierarchical tree top-down, rather than bottom-up and associates particular mutations with each division into subclusters. The motivating hypothesis for this method is that it may yield a better tree topology with more accurate subfamily identification as a result and additionally indicates functionally important sites and allows for easy classification of new proteins. A thorough experimental evaluation confirms the hypothesis. The novel method yields more accurate clusters and a better tree topology than the state-of-the-art method SCI-PHY, identifies known functional sites, and identifies mutations that alone allow for classifying new sequences with an accuracy approaching that of hidden Markov models.
Presentation of a Patient who Underwent Fertility-Sparing Surgeries for Contralateral Recurrence of Ovarian Immature Teratoma with Gliomatosis Peritonei
Authors: Seo Saori , Matsumoto Yoshinari , Tsukioka Miho , Sumi Toshiyuki , Wakasa Kenichi , Ishiko Osamu
Published: May 2013

We report a patient who has maintained a regular menstrual cycle despite undergoing cystectomy and chemotherapy for contralateral recurrence of ovarian immature teratoma with gliomatosis peritonei. We initially performed a fertility-sparing right salpingo-oophorectomy, omentectomy and peritoneal biopsy for immature teratoma with gliomatosis peritonei, with adjuvant chemotherapy; we performed a left ovarian cystectomy and peritoneal biopsy for mature cystic teratoma with gliomatosis peritonei 16 months after the first surgery, a fertility-sparing left ovarian cystectomy and peritoneal biopsy for contralateral recurrence of ovarian immature teratoma with gliomatosis peritonei 60 months after the first surgery, and a left ovarian cystectomy and peritoneal and external iliac lymph node biopsy for endometrial cyst with gliomatosis peritonei 71 months after first surgery. The peritoneal gliomatosis lesions gradually decreased through the 4 surgeries over 8 years. The patient has maintained a regular menstrual cycle and currently shows no evidence of disease.
K-theory, cyclic cohomology and pairings for quantum Heisenberg manifolds
Authors: Gabriel Olivier
Published: May 2013

The C*-algebras called quantum Heisenberg manifolds (QHMs) were introduced by Rieffel in 1989 as strict deformation quantizations of Heisenberg manifolds. It was later shown that they are also examples of generalized crossed products. In this article, we compute the pairings of K-theory and cyclic cohomology on the QHM. Combining these calculations with other results proved elsewhere, we also determine the periodic cyclic homology and cohomology of these algebras, and obtain explicit bases of the periodic cyclic cohomology of the QHM. We further isolate bases of periodic cyclic homology, expressed as Chern characters of the K-theory.
Does full imply faithful?
Authors: Canonaco Alberto , Orlov Dmitri , Stellari Paolo
Published: May 2013

We study full exact functors between triangulated categories. With some hypotheses on the source category we prove that it admits an orthogonal decomposition into two pieces such that the functor restricted to one of them is zero while the restriction to the other is faithful. In particular, if the source category is either the category of perfect complexes or the bounded derived category of coherent sheaves on a noetherian scheme supported on a closed connected subscheme, then any non-trivial exact full functor is faithful as well. Finally we show that removing the noetherian hypothesis this result is not true.
Electrodynamics from noncommutative geometry
Authors: van den Dungen Koen , van Suijlekom Walter D.
Published: May 2013

Within the framework of Connes’ noncommutative geometry, the notion of an almost commutative manifold can be used to describe field theories on compact Riemannian spin manifolds. The most notable example is the derivation of the Standard Model of high energy physics from a suitably chosen almost commutative manifold. In contrast to such a non-abelian gauge theory, it has long been thought impossible to describe an abelian gauge theory within this framework. The purpose of this paper is to improve on this point. We provide a simple example of a commutative spectral triple based on the two-point space and show that it yields a U(1)-gauge theory. Then we slightly modify the spectral triple such that we obtain the full classical theory of electrodynamics on a curved background manifold.
Six-term exact sequences for smooth generalized crossed products
Authors: Gabriel Olivier , Grensing Martin
Published: May 2013

We define smooth generalized crossed products and prove six-term exact sequences of Pimsner–Voiculescu type. This sequence may, in particular, be applied to smooth subalgebras of the quantum Heisenberg manifolds in order to compute the generators of their cyclic cohomology. Further, our results include the known results for smooth crossed products. Our proof is based on a combination of arguments from the setting of (Cuntz–)Pimsner algebras and the Toeplitz proof of Bott periodicity.
Bost–Connes systems, Hecke algebras, and induction
Authors: Laca Marcelo , Neshveyev Sergey , Trifković Mak
Published: May 2013

We consider a Hecke algebra naturally associated with the affine group with totally positive multiplicative part over an algebraic number field

K

and we show that the C*-algebra of the Bost–Connes system for

K

can be obtained from our Hecke algebra by induction, from the group of totally positive principal ideals to the whole group of ideals. Our Hecke algebra is therefore a full corner, corresponding to the narrow Hilbert class field, in the Bost–Connes C*-algebra of

K

; in particular, the two algebras coincide if and only if

K

has narrow class number one. Passing the known results for the Bost–Connes system for

K

to this corner, we obtain a phase transition theorem for our Hecke algebra.

In another application of induction we consider an extension

L/K

of number fields and we show that the Bost–Connes system for

L

embeds into the system obtained from the Bost–Connes system for

K

by induction from the group of ideals in

K

to the group of ideals in

L

. This gives a C*-algebraic correspondence from the Bost–Connes system for

K

to that for

L

. Therefore the construction of Bost–Connes systems can be extended to a functor from number fields to C*-dynamical systems with equivariant correspondences as morphisms. We use this correspondence to induce KMS-states and we show that for

\beta>1

certain extremal KMS

_\beta

-states for

L

can be obtained, via induction and rescaling, from KMS

_{[L: K]\beta}

-states for

K

. On the other hand, for

0<\beta\le1

every KMS

_{[L: K]\beta}

-state for

K

induces to an infinite weight.
Applications of Følner's condition to quantum groups
Authors: Kyed David , Thom Andreas
Published: May 2013

Using the Følner condition for coamenable quantum groups we derive information about the ring-theoretical structure of the Hopf algebras arising from such quantum groups, as well as an approximation result concerning the Murray–von Neumann dimension associated with the corresponding the von Neumann algebra.