bluuebunny/crossref_metadata_2025 huggingface dataset:
Improved Hydrophobicity of Silicon Dioxide Integrated Zinc-Tellurite Glass Surface
Authors: Azmi Syarinie , Arifin Ramli , Ghoshal Sib Krishna
Published: October 2017

Economically viable and maintenance free glass surfaces with improved hydrophobicity are highly demanding in the recent nanotechnology era. Deposition of pollutants and dirt on glass surface that not only causes visual obscurity but also damages the cultural heritages are still to be researched intensely. It is documented that excellent hydrophobic surfaces (with contact angle greater than 90o) can be achieved by controlling the surface wettability, where liquid droplets remain spherical on such surfaces. Selection of materials and the preparation method play a significant role towards such accomplishments. Stirred by this idea, we explored the feasibility of fabricating super-hydrophobic tellurite glass systems by facilely varying the compositions of different constituents. Highly transparent and thermally stable ternary tellurite glass system with chemical composition of (80-x)TeO2 – xSiO2 – 20ZnO, where x = 0.00 to 0.20 mol% are synthesized via conventional melt-quenching method. Samples are characterized using Atomic Force Microscopy (AFM) and contact angle measurements. The impact of SiO2 concentrations variation on the surface roughness, surface energy, and hydrophobic properties are inspected. Glass surface roughness as much as 9.885 nm is attained. The optimal value of water contact angle is discerned to be 101.02° for 0.1 mol% of SiO2 incorporation into the amorphous tellurite host matrix. Besides, the surface energy revealed an inverse proportionality to the water contact angle. This achieved contact angle (greater than 90°) makes this hydrophobic glass surface beneficial for diverse applications. It is established that the present glass composition may be prospective for the development of super-hydrophobic surfaces.
Tracking of Materials and Equipment Used in Planned Maintenance Shutdowns on Offshore Platforms: An Approach using RFID
Authors: Soares P. D. , de Oliveira C. M. , Morales G. , Arica J. , Matias I. , Ferreira A. S. , Carneiro V.
Published: October 2017

Maintenance shutdown tasks on offshore platforms generate large revenue losses for companies in addition to high costs, partially caused by environmental adverse conditions, distances from workplaces, and large volume of materials. The use of an efficient asset controlling and monitoring system reduces these costs and improves their resource management. This work describes the development of a web/mobile architecture system integrated with radio frequency identification (RFID) transponders for asset tracking in maintenance shutdown processes on offshore platforms.

For this study development, we visited an oil and gas company, located in the city of Macaé, Rio de Janeiro, Brazil to analyze its processes. The company was facing problems on its asset management, and tracking material processes. The former takes place in two different sites. It is performed not only on-shore, but also offshore (on oil and gas platforms). Therefore, it was developed a web/mobile system integrated with RFID transponders to tackle these problems.

This system enhances efficiency in processes, reduces costs and losses because of production downtime. Its tracking is able to save up to 5.5 (five and a half) days at the laydown yard and approximately 7 (seven) days on the platform. Besides that, it ensures greater assertiveness, thus decreasing the level of materials’ replacement in the tasks, which was one of the main causes for delays in these processes. Other results are related to its managerial processes. They became automated once the RFID system integrates data in real time, and all the items from tasks defined as priorities were identified. The experimented efficiency suggests to use open source tools to reduce the system development costs, and analyze the use of RFID throughout the oil and gas supply chain, as well as studying other applications and systems in different supply chains, focusing on ways to optimize costs for the company. Additionally, it enabled the monitoring of assets and processes throughout the supply chain, besides providing information and knowledge for companies.
Polyacrylamide Mechanical Degradation and Stability in the Presence of Iron
Authors: Ferreira Vitor H. S. , Moreno Rosangela B. Z. L
Published: October 2017

Polymer flooding enhances oil recovery due to mobility reduction of the injected water, mainly because of the viscosifying capability of the polymer. However, polymer degradation causes viscosity loss. Thus, determining the degradation magnitude is key to a successful polymer flooding. This paper focuses on mechanical and chemical (due to iron presence) degradation mechanisms. The objective is to investigate the impact of these degradation mechanisms on polymer solution viscosity, in both coupled and individual fashions, during a dynamic experiment.

A polymer solution was stored in a stainless steel bottle (at 23°C) and injected in a porous medium at different instants (during three weeks) and flow rates. The flow rates varied from 1.0 cm3/min to 0.25cm3/min and then back to 1.0 cm3/min, in ten steps (duplicates for each flow rate), during the experiment duration. The solution was composed by a partially hydrolyzed polyacrylamide (HPAM) copolymerized with acrylamide tert-butyl sulfonate (ATBS) in a brine of 10.5% TDS containing both mono and divalent ions. Oxygen was dissolved in the solution, and iron was available from the bottle internal wall surface, which resulted in chemical degradation. The flow at different flow rates resulted in distinct levels of mechanical degradation. Rheological data from samples collected before and after injection were compared to evaluate both degradation mechanisms. The polymer concentration in the solutions was confirmed by a UV-spectrophotometer analysis. The iron content was evaluated through inductively coupled plasma optic emission spectroscopy.

The level of degradation in the presence of iron is consistent with other literature for the same polymer. However, the mechanical degradation data is new for this specific HPAM. We divided the chemical and mechanical components of the degradation and quantified the viscosity loss due to each of these phenomena. Additionally, we saw that the mechanical degradation was more relevant at the beginning of the experiment. Although, as time passed, the scenario shifted to a more relevant chemical degradation. We also observed that, for a given flow rate, the mechanical degradation varied depending on the level of chemical degradation of the injected solution. The observed viscosity reduction ranged from 6.1% to 74.2%.

The main contribution of this work is the experimental quantification of two polymer degradation mechanisms as both individual and coupled phenomena.
Fault Reactivation in Compartmentalized Reservoirs: Effect of Fault Transmissibility Enhancement on Pressure Transient Behavior
Authors: Molina Oscar M. , Zeidouni Mehdi
Published: October 2017

A novel application for pressure transient analysis aimed to identify the characteristic pressure response of fault reactivation in a compartmentalized reservoir, where fluid injection/extraction creates a pressure differential across the fault that leads to fault-seal breach, is presented. The analytical solution to two producer wells separated by a sealing segmenting fault is presented. Fault reactivation is incorporated into the model as a fault transmissibility enhancement occurring at the onset of fault reactivation (ts) while pressure distribution at t = ts is used as the initial condition for modeling pressure response after fault-seal breach. The single-well fault slip model is extended to the case of two wells by applying the principle of superposition. The Fourier-Laplace transform is implemented to find the analytical solution to the governing equations before and after fault-seal breach. Asymptotic solutions for early and late-time behavior are discussed too. Pressure and pressure derivative diagnostic plots are presented for various onset times and enhanced fault transmissibilities. In summary, the proposed pressure transient analysis is suitable to 1) diagnose the loss of sealing capability in a segmented reservoir, 2) estimate the threshold conditions that led to fault reactivation, and 3) characterize fault transmissibility before and after fault reactivation.
Best Practices for Decommissioning of Floating Production Systems FPS
Authors: Júnior Samir Leite Alves , Souza Robson
Published: October 2017

Decommissioning of offshore floating structures is predicted to pose significant future challenges for the offshore Oil and Gas (O&G) industry, and will become increasingly relevant as the sector matures, and assets reach the end of their offshore design life. At the present time, the majority of operators are not prepared operationally or procedurally for this stage. Given the number of units due to reach the end of their design life in the next 10 years in Brazil alone, the need for experts in decommissioning or life extension is ever more important.

The O&G industry and the Petroleum Regulatory Agencies are growing increasingly concerned with Decommissioning liabilities and this paper will bring awareness of key aspects relevant to this niche market for safe, sustainable decommissioning and green recycling activities.

This paper aims to present the best practices and solutions related to the decommissioning of FPSO's, and the risks and challenges of sound project execution. The successful execution model consists of procedures related to required assessments to be performed during the planning phase, in order to prepare the decommissioning execution plan, cleaning, voyage / voyage preparation, disconnection and asset disposal.
Discussing Royalties in Brazil in Oil Price Volatility Times: A Public Management Analysis
Authors: Jesus F. D. , Silva T. B. , Resende L. D. , Roitman T. , Silva J. F.
Published: October 2017

Objectives/Scope: The objective of this work is to evaluate the management of revenues from royalties (and special participations fees) by the Brazilian public administration, through the construction of a dependency index to the petroleum sector, to propose new forms of management in the light of international examples and well succeeded theories of public management.

Methods, Procedures, Process: The proposed methodology of the petroleum sector dependence was done through the introduction of an indicator in the form of a composite Index that captures a region's aggregate dependence on its nonrenewable oil and gas resources. The three indicators that make up the Index are the share of export earnings from oil and gas in total export earnings; the share of revenue from petroleum in total fiscal revenue; and the oil and gas industry added value to GDP. Our approach goes beyond the application of an existing index, through an investigation of welfare indicators and further analysis of municipal public data.

Results, Observations, Conclusions: The developed index is useful as a monitoring tool for the management of revenues from royalties and special participations fees. We found that oil fees revenues growth did not generate the same proportion of welfare gains for a local population. Finally, the results drove us to conclude that there is an urgent need for a review of public management regarding the use of these revenues, given the strong dependence of Brazilian municipalities, as well as the known finiteness of natural resources.

Novel/Additive Information: The paper's original contribution is therefore through the introduction of an indicator in the form of a composite Index that accurately captures a region's aggregate dependence on its nonrenewable oil and gas resources. The novelty is the index itself, as well as its analysis and application to municipalities, which will serve as a tool for monitoring and decision making on revenue management, and the elaboration of proposals to better manage natural resources.
Successful Application of Cased and Perforated Completions in Deepwater
Authors: Sathyamoorthy Sekhar , Singh Arvinder P. , Odai Lowestein , Ampim Solomon , Amaning Kwarteng , Boahen Thomas Boakye
Published: October 2017

Most deepwater high rate wells are completed with sand control to avoid sanding issues, especially for a subsea development. However, sand control adds significant Capex to the development besides causing additional pressure drop across the completion. In addition, experiences to date have shown that sand control completions tend to increase in mechanical skin over time due to solids plugging or scaling leading to additional Opex required to stimulate these wells.

This paper describes the key steps taken for two major subsea deepwater developments in Ghana, in order for a paradigm shift towards Cased and Perforated (C&P) completions for full field implementation. Oil production and water injection in both fields are primarily from sand facies associated with Clustered Frontal Splays and Confined Channel Complex. All completions deployed initially were equipped with downhole sand control (mainly Frac and Packs), but driven by well impairment issues early in field life, a thorough review of completion type was initiated which lead to a staged implementation and move towards C&P design for all high rate oil producer and water injector wells.

Modified API RP 19-B Section IV tests were performed using core material from the fields for catastrophic sanding risk evaluation over well lifecycle, and examination of sanding under steady state flow conditions with varying fluid type. Laboratory test results and simulation data were then used to determine safe operating envelopes for the designs. A staged implementation commenced with C&P completions in two wells with the use of High Set Screens (HSS) with capability of bypassing the screens if required and ‘real-time’ downhole gauges to monitor pressure drop across the screens over time. Based on the confidence attained from the sand free production data from both these wells, HSS were removed altogether from subsequent completions.

Well performance data have demonstrated the successful application of C&P completions in typical deepwater turbidite setting. C&P completions have significantly lower skin than other completion types applied in the same fields and are capable of delivering more than 20,000 stb/d oil rates and more than 50,000 b/d water injection rates.
How Technology and an Integrated Project Approach Help Reduce Well Liability Costs during the Decommissioning Phase
Authors: Giskemo Jørn Tore , Marcancola Fernando
Published: October 2017

Exercising environmental responsibility during decommissioning of old assets has become increasingly important during recent years. In addition to increasing awareness in the industry, regulators consistently update and review the regulatory requirements for well abandonment and asset decommissioning.

Operators document liability costs related to decommissioning in their balance sheets. Advancements in project execution and technology adaptation have resulted in regularly scheduled reviews of these liabilities. However, an industry-wide initiative to improve decommissioning execution and efficiency has provided operators direct incentive to review these liabilities more consistently and thoroughly. This paper presents an integrated project methodology to help reduce liability costs by improving efficiency during the decommissioning phase.

This integrated project approach typically begins with a detailed preparation/study phase to predict possible challenges, followed by a design phase for each stage of the project to identify potential costs savings. Well data and regulations are obtained and analyzed according to the specific geographical location and then categorized by the technologies and resources necessary for abandonment. During the technologies and resources phase, potential costs savings are included as part of the plug and abandonment (P&A) service solution. Wells identified as potential candidates for new technology applications are ranked and grouped according to the execution sequence. After this thorough categorization, time and costs estimates are produced for the candidate wells.

This paper presents details of this integrated project methodology combined with recent key technologies to help improve efficiency during well abandonment operations in challenging scenarios. Case histories of the methodology application are also discussed.
Formation Oil Characterization in Oil-Based Mud Environments Using Blind Deconvolution in NMR Data
Authors: Fouraux Mateus Barroso , Tamoto Hugo , Senne Ricardo , Campassi Alvaro
Published: October 2017

The low contrast between formation oil and oil-based mud (OBM) filtrate as well as noise associated in the signal can cause the T2 distribution for the different fluids to resemble each other, making it difficult to identify the formation fluid using nuclear magnetic resonance (NMR) data. One challenges is to quantify the remaining oil volume and estimate the formation fluid proprieties using the diffusion map (T2D) from two-dimensional (2D) inversion. Consequently, it is important to determine new methodologies that can properly enhance the evaluation of such environments.

This paper presents an application of blind deconvolution with a maximum likelihood algorithm processing applied to enhance the NMR diffusion map (T2D), helping to identify, quantify, and characterize the remaining oil volume in an invaded zone. The blind deconvolution algorithm is effective even when no information about the noise is known, making it possible to enhance the T2D map, deconvoluting the point-spread function (PSF) from the signal. After the enhancement, a multiple asymmetric Gaussian fit is used to generate a modeled distribution of the formation oil to estimate the remaining formation oil volume and its T2Intrisic logarithmic mean.

The methodology using the blind deconvolution over the T2 diffusion map was tested. Promising results provided a formation oil distribution consistent with expected fluid properties measured.
Simultaneous Effect of Salt Creep and Dissolution in Caliper Prediction During Drilling Operations
Authors: da Silva B. F. , Longhin G. C. , Waldmann A. A. T. A. , Martins A. L. , Lomba R. F.
Published: October 2017

The Brazilian pre-salt operation presents many technological challenges. Among the key aspects for a successful operation, the choice of drilling fluid is important to avoid structural problems and predict the final well caliper. Drilling operation simulations can be used to indicate operational conditions and assist the choice of the drilling fluid. A simulator has been developed to represent drilling, circulation and static operations involving well drilling processes considering simultaneous effects of solubility and salt creep. The main objective is to avoid wellbore enlargement due to salt solubility in water-based fluids. A bad fluid choice can lead to column imprisonment or a wellbore caliper increase; both effects could compromise the well structure and add difficulties and costs in drillings operations. The model implemented is based in salt transport equations and mass transfer adjusted correlations. The common ion effect is considered in presence of more than one salt. Initial development did not include salt creep and influence of drill cuttings size. The present work adds these effects and evaluates their influence in the final caliper. The salt creep effect is computed as a decrement in well radius, which is obtained in a deformation rate table as a function of fluid density and depth. The authors propose an analysis of salt creep effect and drill size cuttings in a real case study. The need for new adjustments in mass transfering correlations in the solubilization modelling is evaluated and its impacts are presented. The change in the well geometry during drilling, due to solubilization and creep of the salt formations is computed in a dynamic mesh. The application estimates a final wellbore caliper after a sequence of operations in a drilling phase. Such estimate provides arguments for an optimized drilling fluid selection. This work contributes to improve salt drilling operations, avoiding well losses and reducing drilling time and cost.
Intelligent System for Start-Up and Anti-Slug Control of a Petroleum Offshore Platform
Authors: Campos Mario C. M. M. , Ribeiro Leonardo D. , Diehl Fabio C. , Moreira Cristiano A. , Bombardelli Douglas , Carelli Alain C. , Junior Gilberto M. J. , Pinto Sergio F. , Quaresma Bernardo
Published: October 2017

It is difficult to control and to manage wells’ start-up in offshore platforms. In order to solve this problem an intelligent system can play an important role, since available qualitative operator and design knowledge can be easily implemented to assist the operator during wells’ start-up. This paper describes the integration of an expert system associated with anti-slug control for well start-up. The intelligent system has many heuristic rules to implement the automation of the start-up procedures, like the opening choke valve while simultaneously respecting many constraints. Severe slugging flow regimes are one of the major disturbances for the operation of offshore production platforms, and can cause many unplanned shutdowns. Therefore, it’s important to combine start-up intelligent system with an anti-slug advanced control module for each well.

The benefits are associated to reducing possibility of unplanned shutdowns during well start-up operational procedures, decreasing operators’ stress and also helping to minimizing impacts to the environment. A prototype was implemented in one platform with good results for a safe and efficient wells start-up procedure. This paper will present the development and results of this intelligent system for wells’ start-up and anti-slug control for offshore platforms.
Developing a Digital Twin for Floating Production Systems Integrity Management
Authors: Renzi David , Maniar Dilip , McNeill Scot , Del Vecchio Cesar
Published: October 2017

Floating production systems asset integrity management programs are dependent on a combination of inspection, analysis and measured data. These tasks are often labor intensive to perform. A digital twin model combines data and computer models, which can significantly increase the efficiency of these integrity management tasks. A digital twin model has been developed that utilizes typical floating systems measured data and a global performance model. This digital twin model provides an automated continuous assessment of the asset. Eliminating many of the labor intensive activities allows personnel to focus on applying the outcomes of the floating systems assessments rather than performing the assessments. The automated and continuous nature of the digital twin model also allows for a much greater understanding of the behavior of the system, which is the fundamental basis of a successful integrity management program.
Technical Feasibility Study of Steel Catenary Risers for Pre-Salt Field Developments
Authors: Brito Raphael , Aguiar Ludimar , Prado Vinicius
Published: October 2017

So far, off the coast of Brazil, steel catenary risers (SCRs) are only used in the subsea gathering system when connected to a semi-submersible FPU (Floating Production Unit) or a Buoy Supported Risers system (BSR). This paper presents a technical feasibility study for the use of SCRs in the ultra-deepwaters of Pre-salt field (Santos Basin) connected to a spread-moored FPSO (Floating Production Storage and Offloading).

Environmental loads acting on FPSOs cause higher movements than on other types of FPUs (such as semi-submersible, SPAR and TLP). The wave-induced floater motions under the harsh conditions of Santos Basin may generate high fatigue damage at the riser TDZ (touchdown zone). In addition, extreme events may cause a significant compression load on the SCR, inducing global buckling in the same region and, thus, making the TDZ a region of special interest for the design.

To address the issues mentioned above, advanced engineering techniques and effective technologies available in the offshore industry were employed. The study considered different safety classes along the riser, allowing greater flexibility for the definition of safety requirements, and calibrated the fatigue safety factors according to a risk-based methodology. The proposed configuration made use of hydrodynamic dampers and fatigue performance improvement techniques such as upset end pipes and stress relief on critical welds.

The study results indicate the feasibility of SCRs for the operational conditions considered. The use of SCRs potentialy enhances the competitiveness of rigid riser systems for the Pre-Salt fields of Santos Basin when compared with Steel Lazy Wave Risers (SLWRs).
Qualification of Biopolymer in Offshore Single Well Test
Authors: Urkedal H. , Selle O. M. , Seime O. J. , Brandal Ø. , Grøstad T. , Todosijevic A. , Dillen M. , Prasad D. , Ernst B. , Lehr F. , Mahler E.
Published: October 2017

A single well polymer injection and back-production test has been performed at Heidrun, an offshore oil and gas field in Norway. The objective of the test was to verify at field conditions the properties measured in the laboratory for the biopolymer Schizophyllan. This test was part of a polymer qualification program. This paper will give an overview of the single well test and lessons learned.

To ensure high quality data from the test, all elements in the test required detailed planning and following up, including an extensive quality check. The successful execution of the test was possible through a joint active collaboration between the operator, the biopolymer supplier and the service providers. The first focus was on the logistical chain from production of biopolymer, transportation and quality checking prior to injection. The second focus was on the injection, including qualifying polymer mixing equipment for offshore use and preparation for using an injector for both injection and back-production. The third focus was on sampling and analysis where high quality sampling and analysis was a prerequisite for getting conclusive results.

The test was an operational success with no HSE incidents and delivery of an extensive data set, including pressure, temperature and flowrate data as well as of fluid samples. A total of 3,500 m3 of polymer solution including biocide was injected as planned, followed by a short back-production period of 195 m3 for baseline sampling. The remaining polymer solution was shut-in for 39 days before final back-production of 365 m3. Both during injection and back-production samples were taken for later analysis and evaluation of results.

The data confirms that the biopolymer is not being biodegraded during the shut-in period due to efficient application of the biocide injected simultaneously with the biopolymer. The rate and pressure data also supports that the injectivity is maintained during the test compared to water injectivity.
The Effectiveness of the Infraction Notice as a Tool of the Regulation System
Authors: Saad H. C. , Bergamaschi M. B. , Tavares G. R. , Santos M. D.
Published: October 2017

This paper aims to discuss the role of the National Agency of Petroleum, Natural Gas and Biofuels (ANP) in the inspection of fluid measurements, and to present a history of improvement of the issuance of infraction notices, related to the violation of the current resolutions, in addition to their sanctioning implications to regulated agents. In order to carry out this study, the data of all infraction notices issued by the Nucleus of Insspection of Measurement of Petroleum and Natural Gas Production (NFP) from 2010 to 2015 were analyzed, showing the process of finding nonconformities on the measurement systems and how infraction's amount is calculated. In addition, the results of court judgments will be present and, finally, a comparison between the number of infraction notice issued, the infraction committed and the punitive pedagogical implications applied. Futhermore after a critical analysus of each infraction notice issued and its respective nonconmities, it is observed that the most common infraction is the divergence between the values declared in the Daily Production Report and those recorded in the flow computer of the measurement system monitored by NFP. These and other infraction notices generate financial penalties whose are set to force operators to follow the recommendation given by ANP. Petrobras, which is responsible for 94.3% of oil and gas production in Brazil, awsers for most part of infraction notices issued and has paied approximately R$250 million.
New Fiber Technology to Improve Mud Removal
Authors: Engelke B. , Petersen D. , Moretti F. , Halla L. A. , Becker R. , Pagani L. , Revilla R. A. , Martinez A.
Published: October 2017

As drilling muds evolve to satisfy well requirements, cementing preflush technologies need to change to ensure proper mud removal during cementing jobs. A new component—engineering-designed fiber—was added to a preflush fluid and tested in the laboratory, with promising results. The system was then implemented in Latin America.

Obtaining proper mud removal is very important for achieving zonal isolation at cementing jobs. The new technology consists of the addition of an engineering-designed fiber to cementing preflush fluids to significantly improve the removal of nonaqueous fluids from the well during cementing operations. The fibers are compatible with both cement slurries and mud. They work by removing the mud from the casing or formation through two mechanisms: by mechanical cleaning and by attracting the nonaqueous compound of the mud toward itself by hydrophobic-hydrophobic interaction. Two different methodologies were used to evaluate the fiber's ability to enhance the chemical wash and spacer capabilities to clean and demulsificate the nonaqueous mud fluids.

The laboratory tests were performed with cementing preflush fluids with and without the fibers. Results indicated that the preflushes with the fibers were able to clean and demulsificate the drilling mud much more efficiently than preflush without the fibers. Indeed, it was possible to optimize the amount of the preflush surfactants and still obtain excellent results. Some successful cases of field implementation of this technology corroborated the laboratory findings. In both cementing jobs, results indicated very efficient mud removal, and, consequently, zonal isolation and well integrity were achieved.

The fibers were successfully pumped in a field in Latin America. This innovative technology is able to enhance cement bonding in both casing and formation and reduces potential remedial job costs in a wide range of challenging environments.
Development of Low-Manganese L80 HF-ERW Tube Containing 1%Cr with Addition of Boron
Authors: Melo L. C. R. , Cordeiro W. R. , Gomes I. O. , Ferreira M. W. , Filho J. C. Payão
Published: October 2017

The purpose of this work is to present the development of low-manganese pipes containing 1% Cr and Boron manufactured by the HF-ERW process according to standard API SPEC 5CT (2011) L80 grade. The study has an innovative character and the main competitive advantage is the relatively low cost of manufacturing combined with the high level of quality in welding process and subsequent heat treatment of quenching and tempering.

The chemical composition of the steel was designed in such a way to ensure good weldability, high hardenability and low mechanical properties variation after tempering. Low levels of Manganese was established and increase the resistance of hydrogen induced cracking due the tendency of formation of MnS inclusions in the continuous casting. Additionally, levels of 1%Cr were incorporated to ensure corrosion resistance in water injection wells. Hollomon model was used to set the tempering temperature as a function of the aim mechanical property. To characterize the tube, the follow tests were performed, tensile, Charpy, hardness, microhardness, optical microscopy, SEM and CO2 corrosion tests.

The seam weld presented excellent results under UT inspection. The low variability in the mechanical properties shows that the quench and tempering process was stable, which is able to meet the API SPEC 5CT (2011) L80 grade and NACE MR0175 (2003). The scanning electron microscopy identified fine precipitates dispersed in a martensitic matrix, this being the mechanism of secondary hardening which raised the tempering temperature as provided by Hollomon model. The corrosion resistance was compared with N80 and confirmed more than 75% resistance according to the references.

In view of the results we conclude that the low manganese tube containing 1%Cr manufactured by the process HF-ERW meets the requirements of Standard API SPEC 5CT (2011) L80 grade and thereby contribute significantly in increasing competitiveness in the oil and gas production, mainly for the water injection wells by increasing corrosion resistance and offering a tube manufactured by a competitive process compared to seamless.
An All-Electric BOP Control System: A Game-Changing Technology
Authors: Dale John , Rød Magne , Howes Thomas
Published: October 2017

Control system failures in subsea operations are a leading cause of Blowout Preventer (BOP) down-time. The cost of these failures can increase exponentially with water depth. Legacy BOP control systems are based on 90-year-old hydraulics technology and have been stretched to cope with new regulatory requirements and harsher environments. The industry has responded to these design requirements by increasing component sizes, weights, and system complexities. These adaptations have resulted in unintended consequences, such as reduced reliability and an increase in wellhead loading. As subsea operations move into deeper water and wellhead pressures increase above 15,000 psi, legacy control systems may have reached their design limit. This paper introduces a new concept of an all-electric BOP, a game-changing technology that will not only negate these issues, but also improve the safety, efficiency, reliability, and functionality of subsea BOP control systems.
A Novel Approach to Reliability Qualification Testing: Key Constituent in Successful Development of Electrohydraulic Flow Control Device
Authors: Balasubramanian Aswin , Gissler Bob , Shrivastava Pankaj , Saldanha Savio
Published: October 2017

Flow control devices (FCD) play a vital role in an intelligent completion’s ability to enhance reservoir management capabilities by allowing the operator to control inflow and outflowremotely. Among FCDs, the most versatile type is electrohydraulic. However, because these electrohydraulic FCDs are permanently installed in severe downhole conditions, it is important to integrate the reliability qualification testing (RQT) in the overall development effort. This paper describes a novel approach to product development which integrates RQT as a key component.

RQT incorporates testing for all criteria, including function, environment, and reliability. It typically includes accelerated testing, which is performed to reduce testing time while helping ensure product reliability is verified. RQT is applied in the form of a systematic, streamlined, and concurrent verification program to help improve the reliability of the product. Design for reliability (DFR) tools, such as FMEA (failure mode and effects analysis), help identify the key failure modes and failure mechanisms (causes of failure) related to the product. It is of utmost importance to understand these failure mechanisms in detail and correlate them to the stresses applied during testing.

RQT planning uses the analyses performed during the design phase, such as FMEA, reliability predictions anddevelopmenttesting results, to highlight the risks associated with the product. And, further integrates this information to efficiently design the tests. The primaryobjective of RQT is to determine whether the product will meet the mission reliability target. RQT planning not only identifies the need for component reliability testing, but also substantiates reliability targets at the component level. Multiple ingredientsare required todevelop an efficient RQT, such as (a) performing risk-mitigation studies during design phase, (b) defining a mission reliability target at the system and component level, (c) addressing the range of environmental conditions, (d) using accelerated test plans, (e) optimizing test parameters, sample size, test time, etc.

This paper presents an efficient RQT plan, developed for FCD, as well as all associated accelerated testing models for system reliability predictionsand statistical confidence. Also discussed is a uniqueapproach for identifying and integrating key elements of a holistic RQT, which can be used to design an efficient test plan. This approach unites the reliability studies performed during development stages, and further, uses accelerated testing for successful product development, resulting in both cost and time-to-market improvements.
OTIMROTA-Multiline: Computational Tool for the Conceptual Design of Subsea Production Systems
Authors: Fonseca dos Santos Thiago Duarte , Rocha Djalene Maria , Pereira Ladislau Israel , Baioco Juliana Souza , Albrecht Carl Horst , Jacob Breno Pinheiro
Published: October 2017

This article presents a computational tool oriented to develop subsea layouts of oil production system focused on design concepts associated with wet completion. The OTIMROTA-Multiline has been developed by Petrobras in partnership with UFRJ; its goal is to comply with the needs and requirements to develop conceptual design of several subsea systems currently being studied in the Brazilian pre-salt scenarios.

Considering that subsea projects are intrinsically complex, multidisciplinary and comprising of several interfaces, the OTIMROTA-Multiline tool follows two approaches to achieve an optimal solution. The first is based on deterministic methodologies, intended to systematically reproduce design experience with logical restrictions; thus, a large number of candidate solutions can be quickly analyzed, greatly reducing the time to complete the design. The second approach is based on evolutionary algorithms such as Genetic Algorithms to solve the optimization aspects. Both approaches have a large search space, with several interdependent design variables, with complex and quite unpredictable interactions. The final goal is to reduce the overall project costs.

Initially, the computational tool includes facilities to find the best position for a floating production unit (FPU), and to interactively integrate satellite wells in an optimized subsea layout. Compliance with the many design criteria, parameters and requirements is automatically checked, including marine geology and environmental constraints; pre-existent obstacles; simultaneity of offshore operations; risers anchoring, and so on.

Information is available to the designer throughout the tool iterative execution, including acquisition and installation costs for the equipment and flowlines, and expected oil flow rates for each candidate solution. As a final deliverable, the tool automatically provides a formatted report with all relevant results for a proper project selection. The tool also exports a file that can be employed in 2D/3D modeling programs, enabling the best alternative selected to be subsequently detailed by the specialists.

One of the main contributions of developed automation tool will be to enhance the integration among the technical teams through less complex analyses; this will contribute to a more reliable and robust alternative selection, leading to more efficient solutions.

Further developments are currently underway, including new subsea architectures (including production ring, trunkline, manifolds), along with their costs, production flow modeling and the interface with well and topside design to have a more robust tool for evaluation of new architectures.
Geomechanical Model and Wellbore Stability Analysis of Brazil's Pre-Salt Carbonates, a Case Study in Block BMS-8
Authors: Silva Cristiane , Rabe Claudio , Fontoura Sergio
Published: October 2017

In this study, a wellbore stability model was built of the pre-salt area using analytical correlations to obtain an optimum mud window. The operational window assists in optimizing the fluid weight to be used while drilling and is defined by a lower limit (pore or collapse pressure) and an upper limit (fracture gradient). To build a geomechanical model, it is necessary to estimate different parameters. Log data from offset wells, pressure measurements, formation integrity tests, and data from the World Stress Map were used to estimate overburden, pore pressure, rock strength, the magnitude of the minimum horizontal stress, and the magnitude and direction of the maximum horizontal stress. These parameters made it possible to estimate the collapse gradient and define the mud window. The sensitivity analysis of the parameters was performed on the rock strength (UCS) and maximum horizontal stress due to the lack of available data, especially borehole images, 4 to 6 arm caliper, and triaxial tests. The geomechanical model indicates that the overburden in the carbonates of the studied area ranges from 14.0 to 14.6 lb/gal. Pore pressure indicates two different behaviors, presenting slightly over-pressurized (approximately 9.4lb/gal) and over-pressurized in another area (13.2lb/gal). The results of the formation integrity test (leak-off tests) were used to estimate the minimum effective stress ratio (ESRmin), a constant value around 0.65 with a minimum horizontal stress values between 12.4 to 12.6lb/gal in the slightly over-pressured zone and in the over-pressured zone the values are between 13.8 to 13.9lb/gal. The average value of uniaxial compressive strength (UCS) was estimated at approximately 43MPa. The azimuth of maximum horizontal stress was estimated to be approximately 95° and was obtained from the World Stress Map. The effective maximum horizontal stress ratio (ESRmax) was between 0.95 and 1.45, according to the presented scenarios, and the conclusion was that the faulting stress regime was between normal and strike-slip. For the mud window calculation, the effects of slightly over-pressured pore pressure (Pp) and the selected failure criterion, elastic properties and allowable breakouts provided a lower bound limit to the mud window in the carbonates of between 10.0 to 10.1lb/gal and an upper bound limit between 12.4 to 12.6lb/gal for the study area. In the zone with the high-pore pressure gradient, the geomechanical model provided a lower bound limit between 13.3 to 13.4lb/gal and an upper bound limit between 13.8 to 13.9lb/gal.
Parametric Study of the Influence of GOR and CO2 Content on the Simulation of a Pre-Salt Field Configuration
Authors: Pasqualette M. A. , Rempto M. J. , Carneiro J. N. E. , Fonseca R. , Ciambelli J. R. P. , Johansen S. T. , Løvfall B. T.
Published: October 2017

A distinct characteristic of reservoir fluids in different Brazilian pre-salt fields is the high Gas-Oil- Ratio (GOR) and high content of CO2 in the associated gas. In particular, the presence of CO2 in significant amounts is known to have a strong influence on the thermophysical properties and phase equilibria of the oil mixtures. Due to the strategy of re-injection of CO2-rich streams for EOR purposes, these aspects can be even more pronounced in the production fluids in future scenarios. In the present work, a parametric study is performed to investigate the influence of both CO2 molar content and GOR, in a controlled manner, on the simulations of a pre-salt field configuration for various operating conditions. PVT look-up tables were used with a commercial multiphase flow simulator.

First, the thermodynamic modelling of a 20% molar CO2 pre-salt oil was performed, along with well characterized CO2-live oil mixtures taken from the literature, in order to generate PVT look-up tables. They were used to successfully reproduce field data and assess the validity of multiphase flow simulation results from a commercial software. For the CO2-rich live oil mixtures from the literature, a parametric study was performed in which the CO2 molar content ranged from 20% to 50% with 300-600 Sm3/Sm3 of GOR. Simulation results of temperature, total pressure drop, gas volume fraction and gas- liquid density ratio are presented and compared.
Dynamic Model for Production Optimization to Offshore Platforms with Short-Time Machine Failures
Authors: Vieira B. F. , Rosa V. R. , Arraes F. F. , Teixeira A. F.
Published: October 2017

The objective of this paper is to give a support decision tool to help the engineer when main equipments, especially compressors, fail for a short-period, that is to say, a few hours. This is a very complex problem since, according to the transient period of the wells, an intertemporal component is included. Until a steady state is reached again the operator must decide every period (typically every hour or every half an hour) on which wells to close or open, how much gas lift should be injected, how much the chokes should open or close in order to maximize oil production.
On the Hydrodynamic Aspects of the Carbonate Scale Formation Process in High Flow Rate Wells
Authors: Maciel R. S. , Cosmo R. P. , Maciel F. S. , Pereira F. A. R. , Ribeiro D. C. , Aldeia Santo W. , Martins A. L.
Published: October 2017

Easily accessible oil deposits are increasingly scarce, and therefore, more challenging reserves will require innovative solutions and technologies. Carbonate reservoirs are today important resources to be developed. Among the challenges imposed to the flow assurance process, the thermodynamic envelopes for scale formation have been widely studied. This article deals with the additional aspects related to the hydrodynamics of saline scaling of carbonate origin, noticeably calcite. Several phenomena before scaling and should be considered in a global simulation. The forecast of scaling only will represent the reality if all relevant phenomena are accurately described. In this sense, the dynamic growth of calcite crystals influenced by the fluid flow dynamics were investigated using experimental and computational fluid dynamics (CFD) techniques. Experimental data were obtained to evaluate the solid particle size distribution, and these profiles, were the boundary conditions of a discrete phase modeling. The experimental data, coupled with CFD could estimate the scaling rates at high flow rates production wells. The coupling technique constitutes novel contribution to the understanding of carbonate scaling phenomena and can be used to support field procedures for its mitigation, avoiding production losses.