bluuebunny/crossref_metadata_2025 huggingface dataset:
Two-Way Fluid-Structure Interaction in a Flexible Pipe Conveying Gas-Liquid Slug Flow
Authors: Vieiro J. , Ita E. I. , Nydal O. J.
Published: October 2015

Some cases of marine operations with pipes conveying multiphase flows can show structural movements depending on the internal flow dynamics. A floating pipe conveying two-phase gas-liquid flow is an example where a two-way coupling between the internal flow and the structural dynamics is needed. The objectives of the paper is to demonstrate a method for dynamic coupling of slug flow and pipe structure simulations by comparing numerical results with small scale experiments on flexible pipes.

Two small scale experimental setups for two-phase slug flow in floating and submerged flexible pipes were prepared. The experiments were designed to give unstable flows. The air and water flow rates were measured and the pipe movements were video recorded. A new coupled model was established, in which a structural dynamic model has been implemented into a dynamic slug tracking model. Forces due to the internal flow such as fluid weight, friction and centrifugal force were included in the structural model, as well as external fluid drag and soil contact forces among others.

The implemented model can reproduce fairly well the dynamic forces due to the internal flow as well as predict the associated pipe deformations and movements. Slug flow can potentially have an impact on pipe dynamics, in particular for cases where severe slugging can occur.
Subsea Pipeline Vibration Dampers: Mitigation of Vortex Induced Vibrations
Authors: Hahn G. , Masson C. , Norris M. A. , Williams S. L.
Published: October 2015

A study is presented of the potential capacity of pipeline vibration dampers (PVDs) to mitigate vortex induced vibration (VIV) for subsea pipeline spans. The study also makes evaluations for VIV fatigue damage reductions that could be accomplished by PVDs for the spans. While it is recognized that helical strakes and other similar VIV suppression devices are widely used, PVDs are studied herein as a potential standalone option for VIV mitigation or a tool that can be used in combination with strakes. Solutions are presented which indicate that PVDs can substantially reduce VIV of subsea pipeline spans, and there is potential to develop them into practical design tools for such spans. The study is based on the use of representative subsea pipeline span conditions.
Riserless Drilling Technique for Maximizing Bore Hole Stability: Dynamic Kill Drilling Application in Offshore Brazil
Authors: Pessanha W. , Indio M. , Miranda A.
Published: October 2015

As petroleum reservoirs continue to be discovered in ever-increasing water depths, the challenges to drill in these environments become increasingly more difficult. Operations in deep and ultra-deep waters always involve serious risks, which have led the oil industry to invest greatly in research and development of new solutions. The challenges become even greater when horizontal drilling is necessary to enable the production of heavy crude oil from sections located at depths with thin sediments above the production zone. To overcome such problems, it is necessary to increase the well inclination just below the conductor in unconsolidated formations. This difficult well trajectory due to unusual constraints led to the introduction of an innovative technique in Brazil: drilling a riserless and high-inclination directional well using a dual-gradient technique. This paper presents the drilling fluid technologies and procedures that were successfully used to drill the well as it was designed.
Sanding Onset Prediction on a Ultra-Deepwater Well Using a Probabilistic Approach: From Lab to Field
Authors: Ferreira F. H. , Santos E. S. R. , Rossi D. F. , Borba A. M.
Published: October 2015

Sand production is a serious problem in many petroleum basins worldwide. It costs the oil and gas industry tens of billions of dollars annually. Additionally, uncontrolled sand production results in costly workover operations and, in some cases, can result in environment hazards due to the release of hydrocarbons associated with catastrophic wellhead and/or production equipment failure. On the other hand, if an unnecessary sand exclusion completion scheme is adopted in one well it will cause oil/gas production impairment and loss of oilfield revenue. Rock strength plays a main role in the analysis of sanding onset prediction. Regarding that subject, the in situ stress and the reservoir depletion are also important players. This article presents a sanding onset probabilistic analysis that takes into account the uncertainties associated to the determination of rock strength and in situ stress over the predicted bottom hole flow pressure at sanding onset.

In order to determine the sanding onset at a sandstone reservoir, the rock strength will be estimated in three distinct scales: small (uniaxial tests), middle (scratch test) and large (wellbore logs and correlations). According to this procedure, it is possible to scale up the rock unconfined compressive strength from lab to field. In parallel, the in situ stress was estimated considering leakoff tests, minifracs and wellbore logs. Finally, an analytical model is used to estimate the stress around the perforated tunnel. As design criterion, it is not permitted that the maximum hoop stress surpasses the formation effective strength (U). This mechanical rock property is related to the cavity strength registered in a hollow cylinder test.

Using this kind of methodology, in a pore pressure vs. bottom hole flow pressure diagram, failure probability contour maps for sandstones were generated for two of Petrobras' ultra-deep water fields. For the first analyzed field, previously to the analysis itself, wells have been completed with fracpack technology. After performing an analytical and experimental study using the proposed methodology, two wells (gas and oil) were completed in a conventional way. Up to this date both wells are producing without sanding. Throughout the article these wells will be called "Well A". The second field is still at the appraisal phase and wells have been drilled in order to estimate rock mechanical properties and in situ stress state with the purpose of minimizing the proposed methodology uncertainty. Based on this analysis, a long term well test will be performed without any sand exclusion equipment inside the well. Henceforth this well will be named "Well B".

The proposed methodology is an assemblage of an analytical simulation of stress around cavities and an experimental effort to estimate the unconfined compressive strength based on lab tests and wellbore logs in conjunction with empirical correlations.
Walk To Work Offshore Using Motion Compensated Gangways
Authors: Salzmann D. Cerda , Prezzi J. , ten Haaf S. , Groenteman S.
Published: October 2015

This paper describes the operating principle behind motion compensated gangways, how they impact offshore people transfer, the new possibilities and benefits raised by the Walk To Work (W2W) concept. Some examples of vessels designed with this principle are shown.

Ten years ago, W2W with a motion compensated gangway was an unknown concept in the Offshore Industry. People access to offshore structures was basically performed via helicopters or baskets. Nowadays, W2W has become common practice in the North Sea and is spreading all over the world, as a means to increase the number of crew on a platform or to exchange crews in a safe, reliable and efficient way. Active motion compensation technology is the technological driver that enables this innovative concept. The development of accurate sensors, reliable computer power and sophisticated hydraulic and electronics components, motors and actuators, combined with the entrepreneurial spirit of offshore engineers, makes European companies leading in this space.

For the active motion compensation industry as a whole, the ultimate audacious end goal is obvious: eliminate "Waiting on Weather" from the Offshore Industry vocabulary. Although this may be obvious and clear to state, it is definitely a long way ahead of us to actually achieve this vision. However, slowly but steadily, we are getting there. As Walk to Work solutions are advancing in eliminating weather downtime, platforms can be built and commissioned more efficiently, well shutdown durations can be shortened and maintenance or modification work can be planned more accurately. Nowadays, Oil Field Development is required to be all about smarter instead of bigger. The winners of today's oil price fluctuations are the companies that can make use of dramatic decrease in vessel rates and relative cheap shutdown costs, in combination with smart technologies that reduce OPEX costs effectively. The Offshore Industry is a market that is just beginning to open up for the general concept of active motion compensation technology, and at the same time it is essential to embrace this technology in every offshore discipline in order to keep future energy production cost efficient.

Motion compensated crane operations FLNG developments, drilling and well intervention, emergency evacuation are some other offshore activities where active motion compensation is, or will be, a key driver in making the industry smarter and more cost efficient. Offshore motion compensation established itself globally as a reliable part of the offshore ecosystem. But this is only the beginning. The impact on offshore field development budgets can be huge.
System to Telemeasure the Cathodic Protection Potentials Using Fixed Reference Electrodes in Petroleum Platforms
Authors: Bustamante M. A. , Baca A. J.
Published: October 2015

To capture and display the cathodic protection information in the computer screen of the Onshore Engineers that provide the maintenance of the petroleum platforms, this is achieved using a remote system to send the signal from offshore and installing reference fixed electrodes of silver/silver chloride in the legs of the platforms. The problem is that is very difficult and expensive to obtain the cathodic protection potentials below the surface in the legs of the platforms, because of the difficulty to manage the reference electrode in this site. The operator which is located in the ship is the worker who manage and locate the reference electrode. This task is complicated because of the tilt and depth of the platform legs so that the readings couldn't not be so accurate. The wires and the electrode which are hanging from the top of the ship, are thrown to the subsea along the metallic legs to obtain the cathodic potential readings, the movement from waves and position could affect the accuracy of the readings. To avoid this problem, is proposed and recommended to fix the electrodes to de wall of the legs, far away the anodes installed previously in the structures. This is because the potential signal is weaker in far areas. It is necessary to install many reference electrodes to cover the immerse structures; all depends on the cathodic protection arrangement. Each electrode ought to be connected using wire caliper 14AWG/16AWG to a Junction Box that will be located on the top of the platform. The signal will be sent from the junction box, using systems based on satellite and mobile communications technology or telecommunication systems.

Once the fixed reference electrodes be installed, the cost of maintenance will be substantially reduced, because the rent of ships won´t be necessary. On the other hand the readings will be obtained at the moment, just in the instant time. To improve the system is necessary to install a current rectifier instead zinc active anodes in order to send polarization electrons along the structure. There is no a similar job around the world, so that it could be an opportunity to the Cathodic Protection Engineers to improve their systems, minimizing maintenance costs and obtaining information immediately that is obtained
Proactive and Reactive Strategies for Optimal Operational Design: An Application in Smart Wells
Authors: Abreu A. C. A. , Booth R. , Bertolini A. , Prange M. , Bailey W. J. , Teixeira G. , Emerick A. , Pacheco M. A.
Published: October 2015

The primary objective of this study is to quantify the benefit of utilizing smart-well technology. The approach presented here maximizes the expected net present value (ENPV) of a field development strategy while accounting for uncertainty in reservoir parameters. In particular the dominant objective is to quantify the relative merits of adopting proactive and/or reactive strategies when designing optimal control policies from their impact on asset value.

Proactive or reactive control strategies are the methods typically deployed for controlling smart wells in the presence of reservoir uncertainty. In the case of an entirely proactive control strategy, the future operational strategy is optimized based on one's current understanding of the reservoir; this approach does not account for new measurements, as and when they become available, and the improved understanding of the reservoir that they bring. In the case of an entirely reactive control, operational strategy follows rules that are tied to future measurements without recourse to a model-based prediction, e.g., the valve may be closed if significant water ingress is observed. In summary, the proactive strategy seeks to prevent an undesired future result, while the reactive strategy actuates the valves when the undesired event occurs. The approach presented in this article combines these two strategies.

This hybrid approach was evaluated against a reservoir model based on the Namorado field, Campos basin, Brazil. The results are compared with scenarios involving a conventional well, but without smart completions, and an entirely proactive control strategy, that does not consider future information. We demonstrate that the approach yields the highest ENPV. The sensitivity of the approach to changes in the number of time steps used for both proactive and reactive control was also considered. For proactive control, the sensitivity analysis examined frequency of valve adjustment in the absence of new information and for reactive control, how fast one needs to react to new and revealing measurement data. This examination revealed that while being operationally proactive is important, there is no value in planning for frequent valve adjustments when there is an absence of new information.
An International Oil Company's (IOC) Development Projects Overview
Authors: Valente C.
Published: October 2015

Shell's E&P journey in Brazil started back in the seventies when 23 risk services contracts were executed for the exploration in nine onshore and offshore basins. Between the mid-seventies and late nineties, more than 30 wells were drilled on 13 blocks. Almost US$ 400 milion spent on seismic and drilling. This paper presents an overview of field development from the early days to the present.

Between the late seventies and early eighties the discovery of Merluza gas field, in the Santos basin, and other non-commercial discoveries were made. The Merluza development started in the late eighties and was handed over to Petrobras for operation in 1993. The scope considered an offshore platform, subsea infrastructure, wells, gas pipeline to shore and an onshore gas unit.

The Bijupirá & Salema fields, located in the Campos basin, 250 km east of Rio de Janeiro, in water depths between 480 and 880 m, were discovered by Petrobras in 1990 and included in bid round zero. Shell joined the Venture as the operator through the acquisition of Enterprise Oil in 2002 and production started in 2003. It was the first IOC operated development in Brazil with eight producers and six water injection wells. A re-development project resulted in four additional wells with first oil in 2013.

The BC-10 Parque das Conchas deepwater development, also from bid round zero and in Campos basin, is a combination of several distinct small to mid-size fields that allow for phasing. The fields are off the coast of Brazil in about 1800m water depth. This series of successfully phased projects started with the deployment of the Espirito Santo FPSO, 11 wells and subsea boosting equipment in Phase 1 which came on-stream in July 2009. Phase 2 followed on-stream in October 2013 with an additional 11 wells (including 4 water injectors), subsea boosting equipment, and brownfield topsides upgrades on the FPSO. The Phase 3 investment has already added another 7 wells (including 2 water injectors) and will come on-stream in early 2016, after the subsea and topsides scopes are completed.
Practical MPD Deployment Considerations for Floating Drilling
Authors: Bruton J. W. , Lin J. , Patel H. N.
Published: October 2015

Benefits of using managed pressure drilling (MPD) are already widely acknowledged throughout the offshore drilling industry. This presentation will focus on some of the non-trivial issues that must be addressed in the actual deployment of this emerging technology before implementing it to drill from a floating mobile offshore drilling unit (MODU). This information will be based on the authors' recent and on-going experiences. For deepwater drilling, MPD is not widely practiced and is considered as an extension of industry's new technology. Therefore, sharing lessons learned will help to advance this technology.

A major consideration that must be addressed in the initial phases of any MPD deployment includes integration of MPD equipment with the existing conventional drilling systems. A critical choice to be made as early as possible is whether or not to make the MPD systems a temporary or permanent installation on the particular MODU(s) being considered. There are also class society considerations that must be addressed in offshore MPD deployment discussions.

There is a possibility that MPD equipment manufacturers and their vendors may have never furnished products for offshore utilization on a classed MODU. They may be unaware of the many safety and design related issues involved in receiving and maintaining equipment class certification. The paper will also discuss some of these topics, such as: material traceability, MPD equipment design considerations, offshore maintenance, rig implementation with operator, classification society and repair requirements and the constant safety considerations that must be honored.

The next significant consideration in any MPD deployment is related to the actual ownership of the MPD systems being used. Three possible choices exist: the drilling contractor, MPD service provider(s), or the operating company. Each one of these groups carries several unique benefits and bears additional consequences as well. These issues quickly exhibit circular logic, always leading back to the key question: "Are these to be temporary or permanent installations?" On matters such as: personnel training, equipment maintenance, including the spare parts inventory policies, and MPD operating responsibilities, choices will vary, depending on who owns the equipment, and whether or not it is permanently installed on the particular floating MODU(s).

Finally, the crucial roles of risk exposure and risk reduction in making all of these MPD choices will be examined. Regulatory awareness and their approvals for the intended use of MPD technology can be facilitated by class society involvement early in each project. The matter of who owns the MPD systems will play another role in these risks analyses, and the planned mitigations.
Economic Viability to Trigger the Development of Marginal Fields Offshore in the Gulf of Mexico
Authors: Xochipa O. , Galicia S. , Aramayo A.
Published: October 2015

This article is based on a new study for marginal fields Crudo Ligero Marino project, whose purpose was to define a methodology and investment options to meet your goals and profitability criteria.

For this case study, five are considered marginal fields assigned to the project, which have been documented year after year without being able to obtain financing to start their stage of development, that having to compete for financial resources to other more profitable fields. To meet this goal aims to generate improvement levers to achieve those investments meet the criteria of efficiency of capital. These levers will be focused on increasing to meet higher investment income and allowing the project to meet its production targets. To accomplish the above, a methodology based on two stages was used. The first to consider the individual assessment of fields, which involve three main aspects: 1) Analysis of current business case, 2) Identification of initially documented and 3) Analysis levers identified value created by levers, for the definition of using levers. The second stage is the search for synergies to review opportunities for production and consolidation of final results, where aspects of production and investment are determined. This methodology was called as MEAPTEC "Methodology for investment projects applying technical, financial and business levers".

The application of the methodology was made by forming an integrated group consisting of a project manager and technical specialists in static and dynamic reservoir characterization, business modelers and financial analysts.

At the conclusion of the study levers of technical improvement and optimization of investments for the development of these fields they are identified. However, one of them was not possible to achieve improvement has mainly concluded that information is not consistent in its exploratory well.
Numerical Simulations of High CO2 Content Flows in Production Wells, Flowlines and Risers
Authors: Carneiro J. N. E. , Pasqualette M. A. , Reyes J. F. R. , Krogh Espen , Johansen S. T. , Ciambelli J. R. P. , Rodrigues H. T. , Fonseca R.
Published: October 2015

There are several challenges associated to the pre-salt development at the Santos basin, such as long distances from the coast, low temperature reservoirs, high pressures, high water depth, among others. Additional aspects contributing to the complex production scenario are related to fluid characteristics and flow assurance. In particular, the high CO2 content in the dissolved gas is an important characteristic that should be also analyzed, because CO2 is not only a heavy component, when compared to lighter components present in the gas phase, but has also a high Joule-Thomson coefficient. This affects pressure drop and specially the mixture cooling behavior during decompression. The cooling effect is expected to be strong at high production rates. Thus, the objective of the present work is to evaluate these effects under present and future production scenarios, taking into account increasing CO2 contents due to re-injection strategies.

Two different field configurations were investigated and a variety of operating conditions was used, along with real and model fluids ranging from 5% to 50% CO2 content (molar basis). PVT data for the model fluids with high CO2 content were generated by a simulated swelling test with CO2 of an existing mixture with lower CO2 content. A parametric study was carried out aiming at investigating primarily the total pressure and temperature drop in the pipeline when the total CO2 content of the mixture is increased. Furthermore, variation of the fluid properties along the well, flowline and riser was evaluated. Results are also discussed in view of the impact of increasing CO2 contents and the challenges experienced during simulation of such flows.
Exploring the Potentialities of Nanoscience to Enhanced Oil Recovery Process: A Multiscale Computational Approach
Authors: Pereira A. O. , Miranda C. R.
Published: October 2015

The use of smart nanofluids has become an interesting alternative to control and modify the interfacial and wetting properties of liquid-liquid and liquid-solid interfaces. The understanding of how these properties can be modified at the nanoscale and how affects the fluid behavior at the microscale is essential to the development of smart nanofluids for enhanced oil recovery (EOR) techniques. Although the recent experimental advances, the determination of these interfacial properties at nanoscale continues to be a challenge. We proposed an integrated multiscale computational protocol ranging from first principles calculations, molecular dynamics and Lattice Boltzmann method (LBM) to explore the potential applications of smart nanofluids in EOR processes. More specifically, we study the role of dispersed functionalized SiO2 nanoparticles in brine to the oil displacement process in clay pore structures. At first, the montmorillonite surfaces with functionalized Si probe tip model were investigated within density functional theory (DFT) with the generalized gradient approximation revPBE functional with van der Waals density functional (vdW-DF). These results were benchmarked with classical MD calculations. Those previous calculations indicate that the addition of nanoparticles to the brine solution considerably reduces the interfacial tension between oil and brine. Also, a small reduction in oil viscosity and an increase of the contact angle is observed. Here, by mapping the MD results into LBM parameters and simulating the oil extraction process by a nanoparticle solution at the microscale, we observed that the inclusion of nanoparticles indeed improve the oil displacement process in realistic pore network models. The improvement in oil recovery was evaluated for different rock geometries, porosity and permeability. The proposed multiscale approach can be a useful tool to explore potential chemical additives for EOR and investigate the effects of the interfacial and wetting properties on fluid behavior at both nano and micro scales.
Anti-Slug Advanced Control for Offshore Production Platforms
Authors: Campos M. , Meien O. , Neto S. , Stender A. , Takahashi T. , Ashikawa F.
Published: October 2015

The application of advanced control techniques in offshore oil production plants is a challenge. There are many changes in operational points in time, for example, the process is affected by the natural oil well's behavior dynamics. Besides that, limited instrumentation available has to be considered when thinking in oil optimization and control. In order to improve the scenario, taylor-made advanced control modules have been developed for those units. The present article will present development, implementation and results of anti-slug control for four platforms located at Campos and Santos basins. Severe slugging flow regimes are one of the major disturbances for the operation of offshore production platforms. Slugs can occur, for example, in pipeline-riser systems that transport oil and gas mixture from the seabed to the surface and they are characterized by severe flow and pressure oscillations, with moments of high instantaneous liquid or gas flow, which is then followed by moments of almost no flow. This cyclical phenomenon can cause many problems like reduction in process efficiency, and production losses due to many unplanned shutdowns.

One of the ways to minimize issues associated with slugs is to use advanced control techniques in wells. These techniques utilize the available measurements, as downhole pressure (PDG) and top side pressures, to define a choke valve position that minimize or even eliminate slug instability. The objective is to have a stable flow together with the maximum possible production rate. One great challenge for this anti-slug control is how to deal with plant nonlinearity, because the process gain of the system changes drastically at different operating conditions. So, we will discuss in this paper different control algorithms to deal with this problem.

This paper will present an anti-slug advanced control, which has three subsystems: one responsible to diagnose and identify slugs, considering some pressures patterns; other to control or minimize slugs; and finally one to protect the process plant in case of severe disturbances. Finally, this paper will show and discuss some economic and safety results of the implementations of these anti-slugs advanced control systems in offshore platforms, emphasizing the benefits obtained, which are related with stability, energy efficiency, and profitability due to a important decreasing in unscheduled compressor shutdown events, as well as increasing in operational efficiency. It will be shown that operators have well accepted this system and are maintaining this controller in automatic mode in more than 80% of the operating time.
Offshore Waste Water Management System Reduces Operating Costs
Authors: Usher M. , Herrington D. , Kozikowski M. , Scott E.
Published: October 2015

Regulatory constraints governing the discharge of contaminated waste water in offshore operations are increasing across the world. In most regions, contaminant (oil) levels above 30 mg per liter are strictly monitored and regulated to protect our environment. These regulations prohibit disposal of contaminated material offshore, forcing this "slop" water to be transported from the rig to shore for proper treatment and/or disposal. The costs associated with transport, handling, and disposal are incremental to the drilling operations and drive up the cost of the well. These additional rig and logistical operations further expose rig personnel to potential health and safety risks by burdening the crew with additional activity and movement of materials. The intent of this paper is to show the performance capabilities of an innovative waste management system that has been proven capable of reducing the slop water volumes in offshore operations by as much as 80%.

A novel waste management system has been developed and designed specifically to reduce the costs associated with offshore waste water management. The technology has been performance tested to prove that it can efficiently remove the contaminants required to allow clean permeate to be discharged to sea. Testing conducted to confirm system capabilities utilized genuine offshore slop water at various levels of contamination. Waste contents tested ranged between 1% and 10% and were comprised of both oil and solids.

Performance testing has been successful for over one year with no visible suspended solids detected in the resulting permeate. All concentrations tested showed the quality of permeate produced to be below the 30 mg/liter oil in water threshold, qualifying it for discharge to sea. Additionally, the reliability and maintenance needs of the system were benchmarked to confirm operational efficiency and cost requirements.

The system's performance has shown the ability to significantly reduce the volume of waste/slop water that would otherwise have to be transported to shore and treated/disposed of as prescribed by regulatory agencies. The system's ability to remove these contaminants directly results in reductions as high as 80% in the volumes being shipped to shore for treatment and disposal and consequently a significant reduction in disposal and handling costs.
Considerations of Adjusted Brine Chemistry for Waterflooding in Offshore Environments
Authors: Alvarado V. , Garcia-Olvera G. , Manrique E. J.
Published: October 2015

The work addresses technical issues of waterflooding operations in offshore environments from the standpoint of fluid-fluid and rock-fluid interactions. Seawater is the preferred source of injection fluid for waterflooding in offshore reservoirs. Given the elevated CAPital EXpenditure (CAPEX), seawater treatment is generally driven by the need to mitigate injectivity loss or water compatibility issues such as the formation of hard scales. The emergence of engineered water as an enhanced-oil recovery (EOR) process has prompted the need to adjust seawater chemistry. Water chemistry modification, however, is a reservoir specific process in our view. Here, we analyze fluid-fluid as well as rock-fluid interactions for two heavy-oil carbonate reservoirs in the Gulf of Mexico to show that geochemical interactions upon adjustment of brine chemistry can lead to undesirable results depending upon lithological characteristics.

Crude oils from two offshore carbonate reservoirs in the Gulf of Mexico were used in experiments. Synthetic reservoir brine was prepared based on produced water analysis. Shear and dilatational rheology were employed to estimate interfacial moduli of crude oil-brine systems, for several water chemistries. These dynamic interface properties have been found to contribute to EOR mechanisms in low-salinity waterflooding. Three different carbonate outcrop samples were used to characterize single-phase rock-fluid interactions in coreflooding experiments. Effluent samples were collected to determine cations and anions concentrations and thereby calibrate geochemical models. We contrasted the needs of seawater modification with availability of viable technologies for offshore operations, such as reverse osmosis, to envision feasible optimization of brine chemistry.

Results show that geochemical interactions upon modification of equilibrium conditions in reservoirs resulting from injection of adjusted brine chemistry can lead to in situ alteration of water chemistry in a way that it impairs EOR benefits of adjusted brine chemistry injection. This is particularly severe when low-ionic strength is selected for injection in anhydrite-containing carbonate reservoirs. On the other hand, current sulfate-reducing strategies to avoid scaling in sandy reservoirs run contrary to proposed sulfate-enrichment in several oil-producing provinces. Current technologies appear to enable a broad spectrum of water chemistry modification, but implementation in offshore environments might be prohibitive for some designs.

The combination of experimentally calibrated geochemical modeling with interface rheological characterization, in light of current seawater treatment technologies, offers a novel strategy to guide optimum water design for adjusted brine chemistry waterflooding operations.
CFD Simulations of Multiphase Flows Containing Large Scale Interfaces and Dispersed Phases with Selected Production Technology Applications
Authors: Johansen S. T. , Mo S. , Meese E. , Oliveira J. E. S. , Reyes J. F. R. , Carneiro J. N. E.
Published: October 2015

Multiphase flows in oil- and gas pipelines involve a variety of different flow regimes. The different flow regimes are determined by the geometric arrangement of oil, gas and water inside the pipe, and evolve in a dynamic manner along a flowline, from bottom hole to receiving facilities. Along the path of the flow, the geometric fluid arrangements (or flow patterns), which develop dynamically, are often outside what is properly accounted for in existing 1D flow models. In such cases, more detailed multidimensional models are needed. As the industry is facing tighter operating margins and stricter regulatory frameworks, more accurate and predictive tools are needed. It is realized that CFD (Computational Fluid Dynamics) type models cannot replace 1D models in most cases, but will be an extremely valuable addition to the toolbox in cases where the 1D models may be insufficient.

In the present paper a CFD method will be presented which enables such generic simulations. In this model, the physics of coexisting large scale interfaces and dispersed fields (droplets and bubbles) has been handled. Results obtained by a "Quasi-3D" implementation of the model will be shown for a number of important industrial applications. It will also be shown how such tools can also be applied to improve existing 1D frameworks, or directly to tackle multiphase production technology challenges.
Field Results of the First Brazilian Pre-Salt Multi-Fractured Sub-Horizontal Well
Authors: Azevedo C. T. , Neumann L. F. , Denadai N. J. , Chagas C. M.
Published: October 2015

Petrobras pre-salt discovery is a huge hydrocarbon reserve located below an extensive layer of salt at about 5000 m depth. So far, the wells drilled at this scenario found light oil in highly heterogeneous carbonates reservoirs. The formation permeability varies more than four orders of magnitude. Some fields have most of the permeable zone with values ranging from 1 to 10 mD and this scenario requires stimulation in order to maximize productivity. This article will present the first multi-fractured sub-horizontal well constructed in the pre-salt reservoir.

In this stimulation operation 8 acid fractures were created in a sub-horizontal open hole well. This article will show the completion selected that permitted to register the bottomhole data above and below the zone where the fracture was being created. This record allowed the interpretation if the fractures were really created in the zones selected or if there were communication between zones. The article will present the calibration tests results, the fracturing data of all intervals and some insights regarding fracture orientation due to temperature behavior.

The reservoir depth and the proximity of the salt layer bring many challenges regarding hydraulic fracturing operations. This operation and other field results have shown minimum in situ stresses in the magnitude of 0.7 psi/ft and fracture propagation pressure that exceeds the estimated overburden. The records of the bottomhole pressure during this operation showed that there were some communication between zones. After the stimulation operation, a formation test was done measuring the well productivity and collecting samples of the reservoir fluid. The samples collected were analyzed and the tracers used during the stimulation were identified, indicating which fracture was contributing to production. The data registered during this operation is a huge lesson learned about doing multi-acid fractures in a carbonate reservoir for all the industry.
Developing Corrosion and Erosion Resistant Technology for Sand Control in Oilfield Applications
Authors: Carrejo N. , Mann C. E. , Wibowo H. , Gaudette S. L.
Published: October 2015

As the oil and gas industry moves toward drilling ultra-deep, high-pressure wells with more challenging completions, emerging technologies will be required to increase the reliability of current sand control products and methodologies. Investigations in sand control and particle retention have led to the development of several different design methodologies. Gravel packing is one technology used in many openhole wells today. When gravel is pumped downhole, an understanding of the particle packing around the screen helps determine theoretical porosities. Because there is no way to determine the particle packing of a gravel screen, a combination of cubic and rhombohedral packing is estimated to provide pore throats with a maximum diameter that ranges from 24% to 30% of the median grain size used within the gravel screen. When investigating the effectiveness of gravel-packed screens, the overall permeability of the gravel pack and screen must be 25 times that of the permeability of the formation1. The data shows this would maintain an increase in relative production and emulate a screen with infinite permeability. The development of a high-strength bonded bead matrix (BBM) is one such technology that incorporates the sand control efficiency of a gravel pack into a metallic sand control media. The BBM has a high unconfined compressive strength (UCS), is corrosion resistant, erosion resistant, and can have its geometry tailored to fit each application with engineered pore sizes. The BBM is a rigid pack of spheres that provides permeability between 100 and 1500 Darcy while allowing the production of fines smaller than 43µm to prevent plugging. Due to its high resistance to erosion and corrosion, the BBM is suitable for harsh environments, acid treatments, as well as injector and producer wells. In addition, the BBM is integrated into the base pipe wall, allowing a larger bore and a higher pressure alternative to conventional screens. This bonded bead screen (BBS) can be run with a frac sleeve or other monobore multi-zone systems. It can also be drilled in hole with a casing bit system or steerable drilling liner assembly to prevent a separate screen run, further limiting operational costs that can be crucial to limiting non-productive time as well. This paper outlines the development of this sand control technology and discusses the inclusion and functionality of the BBM within many applications.
Overview of CFD Multiphase Flow Simulation Tools for Subsea Oil and Gas System Design, Optimization and Operation
Authors: Gharaibah E. , Read A. , Scheuerer G.
Published: October 2015

Due to the recent drop in the oil prices, the oil and gas industry is experiencing tremendous pressures to reduce costs. This is especially true for both Subsea Production Systems (SPS) development and operations to ensure profitability while meeting increasing regulatory requirements.

In the last years, the modelling and simulation of multiphase flows has become a powerful engineering tool to conduct virtual experiments during design and development for many industries, such as aerospace, automotive, energy and healthcare. This is mainly due to the significant improvement of the modelling approaches which include more details of multiphase flow physics and phenomena. An additional growth contribution is due to the rapid development of the computational resources and computer power.

The oil and gas industry can benefit from high fidelity multiphase flow modelling and simulation tools to minimize the cost of production system design during the project development phase as well as to support optimized operation and assessment of production performance. Because of the low-risk virtual environment, the use of multiphase flow modelling and simulation tools will also reduce the cost of physical testing, assist development of new technologies, and the evaluation of novel concepts.

The objective of this paper is to provide an overview of the state-of-the-art of multiphase flow simulation tools and their recent evolution and adaptation for subsea applications. The focus is on multiphase flow modelling using Computational Fluid Dynamics (CFD) simulation tools, and in particular on their capabilities and limitations when applied to predict the hydrocarbons behavior throughout their journey from the reservoir to the processing facility. Applications of multiphase CFD tools to support the design, operation and monitoring of SPS and the developments and validations required for replacing costly laboratory tests, component qualification and field tests are also addressed and discussed.
Impact of Notch1 Deletion in Macrophages on Proinflammatory Cytokine Production and the Outcome of Experimental Autoimmune Encephalomyelitis
Authors: Wongchana Wipawee , Lawlor Rebecca G. , Osborne Barbara A. , Palaga Tanapat
Published: October 2015

Notch signaling is involved in regulating TLR-mediated responses in activated macrophages. In this study, we investigated the impact of Notch signaling in macrophages in an experimental autoimmune encephalomyelitis (EAE) model. To examine the impact of deficiency in Notch signaling in activated macrophages in EAE, an adoptive transfer of activated macrophages derived from Notch1fl/fl × Mx1cre+/− (Notch1 knockout [N1KO]) or CSL/Rbp-jκfl/fl × Mx1cre+/− (CSL/RBP-Jκ KO) mice was performed prior to induction of EAE. Mice receiving activated N1KO macrophages showed decreased severity of EAE compared with mice receiving wild-type or CSL/RBP-Jκ KO macrophages. In vitro restimulation of splenocytes by myelin oligodendrocyte glycoprotein 35–55 peptide from these mice revealed that cells from mice receiving N1KO macrophages produced significantly less IL-17 compared with the control mice, whereas IFN-γ production was similar in both groups. We found that activated N1KO, but not CSL/RBP-Jκ KO, macrophages produced less IL-6 and had lower CD80 expression compared with wild-type and did not exhibit any defect in IL-12p40/70 production, whereas activated macrophages from CSL/RBP-Jκ KO mice phenocopied γ-secretase inhibitor treatment for reduced IL-12p40/70 production. Furthermore, the nuclear translocation of the NF-κB subunit c-Rel was compromised in γ-secretase inhibitor–treated and CSL/RBP-Jκ KO but not N1KO macrophages. These results suggest that Notch1 and CSL/RBP-Jκ in macrophages may affect the severity of EAE differently, possibly through modulating IL-6 and CD80 expression, which is involved in the Th17 but not Th1 response.
Tibialis anterior muscle needle biopsy and sensitive biomolecular methods: a useful tool in myotonic dystrophy type 1
Authors: Iachettini S. , Valaperta R. , Marchesi A. , Perfetti A. , Cuomo G. , Fossati B. , Vaienti L. , Costa E. , Meola G. , Cardani R.
Published: October 2015

Myotonic dystrophy type 1 (DM1) is a neuromuscular disorder caused by a CTG repeat expansion in 3â€™UTR of DMPK gene. This mutation causes accumulation of toxic RNA in nuclear foci leading to splicing misregulation of specific genes. In view of future clinical trials with antisense oligonucleotides in DM1 patients, it is important to set up sensitive and minimally-invasive tools to monitor the efficacy of treatments on skeletal muscle. A tibialis anterior (TA) muscle sample of about 60 mg was obtained from 5 DM1 patients and 5 healthy subjects through a needle biopsy. A fragment of about 40 mg was used for histological examination and a fragment of about 20 mg was used for biomolecular analysis. The TA fragments obtained with the minimally-invasive needle biopsy technique is enough to perform all the histopathological and biomolecular evaluations useful to monitor a clinical trial on DM1 patients.
Primary hepatic Ewing sarcoma: a very infrequent case report
Authors: Ates Ozturk , Bugdaycı Basel Fatma , Bozdogan Nazan , Aksel Bulent , Oksuzoglu Omur Berna
Published: October 2015

Ewing sarcoma (ES) is a member of small round cell tumors of which contains Wilms’ tumor, neuroblastoma, rhabdomyosarcoma and lymphoblastic lymphoma. ES occurs most commonly in the bone but infrequently occurs in the soft tissues without involvement of the bones. Primary involvement of the liver is even rarer. We report the case of 24-year-old female patient with abdominal pain. Abdominal computed tomography scan showed hepatic large cystic lesion. Liver biopsy showed tumoral cells with small narrow stoplasmic and hyper chromatic nucleus evaluated as small round cell tumor. Immunohistochemical study of the lesion revealed CD99 and bcl-2 positive, cytokeratin, LCA, CD138, chromogranin, synaptophysin, myoD1, terminal deoxynucleotidyl transferase and myoglobin negative the diagnosis primary hepatic ES. A research for any other tumor involvement by using positron emission tomography yielded only hepatic involvement revealed. The patient treated with vincristine-cyclophosphamide- adriamycin and ifosfamide-etoposide alternately chemotherapy then hepatic tumor regressed. Patient operated on hepatic wedge resection. She has continued on chemotherapy and she has been doing well at the sixth month of diagnosis.
An exploration of the idea of ecodomy in Calvin's view of God and the world: Its implications for churches in South Africa today
Authors: Pillay Jerry
Published: October 2015

The Faculty of Theology chose as its theme oikodome, which speaks about the fullness of life for all. This article explored this theme by looking at John Calvin�s understanding of God and the world. In this article, working from the premise of the sovereignty of God, the author attempted to show that undergirding Calvin�s theology is the idea of oikodome. The author showed that for Calvin everything in life is connected to God and thus the idea of oikodome is deeply rooted in Calvin�s theology. The author illustrated this by examining significant themes in Calvin�s teachings on the Trinitarian God, creation, humanity and providence, state and church, transformation of society, concern for the poor, and education. The author used this information to show what implications the idea of oikodome has for churches in South Africa today, especially in the context of poverty and struggle. The author calls on churches to embrace the theological foundation explicated by Calvin in their endeavour to work toward the fullness of life for all people.