bluuebunny/crossref_metadata_2025_split huggingface dataset:
Offshore Exploration in the Argentine Sea
Authors: Arismendi S. M. , Bolatti N. D. , Coenes V. E. , Astengo D. M. , Peirotti E. M. , Kress P. R. 
Published: October 2023

Abstract
The Argentine Sea is one of the largest and less explored regions of the planet. It has a potential of billions of barrels of oil to be investigated. The country's great challenge is to verify and develop this potential in the framework of narrow transitions to alternative energies and decarbonization. For unlocking this hydrocarbon potential, a Play Analysis methodology was applied to the entire Argentinian margin. The large volume of resources detected (+30.000 MBOE) is now being associated with scientific evidence related to the opening of the south Atlantic and recent discoveries on the conjugate south African margin. Besides, a series of actions such as intensive 2D seismic acquisition in deep waters, oceanographic surveys, and the extension of the limit of the continental platform, allowed the country to launch in 2019 its first exploration bidding round since the 1960's. The bidding round was a success in terms of Major energy companies’ interest and investment, ending with the granting of 18 exploration permits. Commitments assumed by companies in these exploration areas are mainly the acquisition of seismic data during a first exploration period. Then, a drill or drop decision must be made to pass to a second period. However, recent changes in Regulations for environmental permits, together with a greater social environmental awareness, led YPF as the National Oil Company, to develop diffusion activities to get the social license to operate. One of the requirements that new regulations introduced, are mandatory public hearings to find out the opinion of the society for each offshore activity. In the first offshore public hearing, only 3% of participants supported the activity but, after strong diffusion effort, the following public hearing registered a 63% of approval. This new context shows that environmental and social demands are a new challenge for the offshore oil & gas activities within the framework of energy transitions and carbon neutrality. It is a priority to respond the concerns of society and demonstrate that the activity could fit in the transition while generating and developing jobs, industries, technical and scientific knowledge, and favorably impacting the economic and social fabric of the country.
Structural Design of a Floating Offshore Wind Turbine Foundation
Authors: Pacheco A. A. , Moreno C. A. S. , Faisca R. G. 
Published: October 2023

Abstract
Nowadays, there is a search for renewable energy sources that are more attractive in terms of cost-effectiveness. Thus, the wind has been considered as one of these sources. Therefore, wind turbines have been installed. As a consequence, it is necessary to develop technologies, mathematical models, capable of analyzing the behavior of the structure in operational and accidental conditions. The present research is mainly focused on the structural design and analysis of a floating offshore wind turbine foundation, which supports the tower of the turbine. Furthermore, the work includes the behavior analysis of the platform in four different conditions: Intact, one broken line, two broken lines and three broken lines. For each condition, it was evaluated the effective tension of the mooring lines extremities. Thus, it was possible to check the mooring lines MBL (Minimum Breaking Load), and finally, it was checked too, the stress levels at the base of the tower. To fulfill the established objective, initially, the shape of the platform was idealized, the thickness of the platform plates were designed, the material plates were defined, etc. After, motion analysis was carried out using the OrcaFlex and AQWA softwares. Subsequently, a mooring system was designed, thereby, for the proposed case study, a global numerical analysis of the system was performed, using the OrcaFlex software, imposing the environmental loads. Finally, the results in terms of the platform motions, mooring lines effective tension and stress level at the base of the tower were evaluated. Therefore, the intact and accidental condition of the platform were analyzed for the wind turbine supposedly installed in the region of Rio de Janeiro, Brazil.
Mineralogical Characterization of Mature Oil Well Cement Pastes Exposed to Downhole Conditions for 30+ Years
Authors: Mello e Alvim Thiago Monteiro , Beltrán-Jiménez Katherine , Gardner David J. , Toledo Filho Romildo Dias , Mendoza Reales Oscar A. 
Published: October 2023

AbstractThe objective of this work is to characterize the alteration on cement pastes exposed to 30+ years of natural ageing at downhole conditions. The cement samples used in this study were recovered from two production wells drilled in the Norwegian continental shelf completed in the late 1980's. Sandwich sections comprised of an inner and outer casing section with cement in between were recovered to surface prior to well abandonment. After recovery, cement samples were cut and studied to investigate signs of alteration and degradation. The characterization was performed using chemical and mineralogical characterization techniques such as: Thermogravimetric Analysis (TGA), X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM) and X-Ray Fluorescence (XRF). Along with the two well cement samples, an additional class G cement, control sample, was produced and cured in control condition so that it could be used as a reference for a younger cement.The cement samples studied in this article were not exposed to aggressive agents such as CO2 and H2S either at downhole conditions or in the lab, therefore the main driver for alteration or degradation was ageing. The results indicate that after an exposure time frame comparable with the service life of an oil well at relatively low temperatures, the conditions did not induce significant chemical or mineralogical changes. When comparing the recovered samples with the control sample, the main alteration identified was the higher level of carbonation process. This process indicates natural ageing of the cement during the 40-year period that finally led to a reduction of strength. This work supports the understanding of the durability of well cement and well integrity. The results presented help to establish a base line and to identify the alteration and degradation due to ageing through the end of the wells production life and the start of the abandonment phase.
Enhancing Predictive Models Through Cuttings Reinterpretation: An Ecosystem to Leverage AI Applications for Well Drilling Technologies
Authors: Oliveira L. H. L. , Nóbrega T. , Jacinto M. V. G. , Medeiros D. R. , Silva M. A. , Medeiros G. C. , Montalvão L. C. , Sátiro L. S. P. , de Almeida R. V. 
Published: October 2023

Abstract
This paper discusses a methodology to enhance machine learning (ML) models developed to predict lithology from real-time mud logging data. Inaccuracies of geological data obtained in the field can lead to inconsistencies in model predictions. To address this, drilling cuttings collected from the field were transported, re-described, and re-evaluated by a team of geologists in a laboratory environment with more favorable conditions. The analysis process carried out was composed of consistent and robust analysis methods and processes, such as microscopic examination (for rock type identification, percentage of each lithotype, color, texture, hardness, cement/matrix material, accessory minerals and fossils, sedimentary structures, and visual estimation of porosity), HCl (10%) test, and fluorescence to describe the cuttings samples. Additionally, calcimetry was used to determine the percentage of carbonate in the rock samples. The results of this study demonstrate that a more accurate reinterpreting of cuttings samples can increase the predictive capability of the ML model (which was able to estimate expected lithotypes with greater reliability). It is worth noting that the continuous description of new samples from other wells in various geological contexts of the same basin is fundamental to improving model performance and making it more trustworthy and representative of reality. One of the importance of these models is to assist the geologist in estimating the rock type being drilled in real-time, based on drilling parameters and gamma-ray data. In this sense, the model becomes more reliable during the decision-making process in drilling operations, contributing to the effectiveness, efficiency and automation of exploration for oil and gas fields. These findings have important implications for the development and implementation of ML solutions in the O&G industry, highlighting the importance of continually improving geological databases to enhance the accuracy and reliability of such models.
The Challenge for the Oil & Gas Industry to Face a New Way of Working
Authors: Paiva R. L. , Silva J. B. , Gonzalez L. J. 
Published: October 2023

Abstract

OBJECTIVES
As a result of the COVID-19 pandemic, most companies had to adopt home as an office to stay safe and continue operations. Based on the above, the purpose of this article is to present how a cloud solution helped Oil & Gas companies adopt a new working scheme during a global health crisis.

PROCESS
With the introduction of cloud solutions to help transition to a new working scheme, it was necessary to implement a migration process that would be the least impactful to both operations and end users. This migration process consisted of the following elements: (1) Infrastructure preparation based on workflows executed and computational demand;(2) Data Migration defining what is priority and what is not; (3) On boarding sessions guiding the users during the adoption of new way of working, explaining the new infrastructure, how to connect, find data, request support, and how the backup works, and (4) Online support avalable24*7 managing basic, medium, and advanced levels.

CONCLUSIONS
The emerging new way of working taught us that integration of teams can be achieved digitally, and independently of where teams are located under the following premises: : (1) The infrastructure was prepared to face company's needs, like disk space, workflow demand and memory; (2) Data was available in an organized, clean, and single environment; (3) Data was protected in very rigorous backup plan; (4) Users were able to work in a collaborative, secure and confident environment that let them to reach their business objectives during the pandemic; (5) A Support system was in place to guide the users during the transition and adoption phase; (6) The pieces of the puzzle (infrastructure, data, applications, users) were integrated to give the Oil & Gas business the continuity it needed in a difficult period of consolidation.
A more intelligent work framework is available, where artificial intelligence is used to create automatic interpretations improving considerably the time dedicated to critical tasks and allowing end users to focus on other jobs. Data Managers and Infrastructure Engineers can use this document as a reference of how crisis have been addressed in the past and how project innovation and digital enhancements have been a key part of the solution.
Static Modelling and Fault Seal Analysis of the Migrant Rollover Structure, Sable Subbasin, Offshore Nova Scotia, Canada
Authors: Martyns-Yellowe K. T. , Richards F. W. , Watson N. , Wach G. D. 
Published: October 2023

AbstractCrestal faulting can lead to breach of trap integrity and leakage. The Migrant structure is an example of a potentially breached trap due to fault leakage and juxtaposition. In this paper we use 3D geocellular modeling, populated with new interpretation of input parameters, including shale volume, to examine the possible mechanism for leakage (crestal faulting). A fault plane profile (Allan diagram) was constructed, which can be taken a further step into dynamic modelling and simulation (not presented in this study).Located in the Sable Sub-basin, the Migrant structure is a fault controlled, four-way dip anticlinal closure, which formed as one of a series of related structures during rift basin extension, sediment loading and salt mobilization in the Cretaceous. Genetically related rollover structures (e.g., the Distal Thebaud Field) in a similar structural and stratigraphic setting have proved viable as a commercial trap.The Migrant N-20 well was drilled to test for hydrocarbons trapped in Late Jurassic to Early Cretaceous deltaic and fluvial-deltaic reservoirs in the structure. The well encountered gas from a deep sand reservoir during drill stem testing (DST 2) with a reported flow rate of 10 million standard cubic feet per day. However, over the duration of the test, an associated decline in flow rate and pressure depletion was observed, which led the operators to consider the target reservoir as non-commercial.In this paper we present a re-appraisal to assess why this trap failed by integrating well data (logs, checkshot and pressure) and 3D seismic to produce a static model demonstrating the trapping mechanism in the Migrant Structure. Initial observation of the 3D seismic shows shallow crestal faults while preliminary observation of well logs from the Migrant N-20 well suggests a diminishing sand/shale ratio from the shallow to deep sections of the trap.This study of the Migrant Structure contributes to the understanding of the relationship between reservoir and seal thicknesses relative to fault displacement and its role in subsurface fluid trapping or cross-fault leakage, through upward and outward displacement (stair-stepping) between reservoirs of different ages across a given fault.The paper shows how data integration and workflows have been combined effectively and is an important contribution for risk assessment in the Sable Subbasin. The proposed model can be applied in other basins including the similar salt cored basins like those offshore Brazil.
Well Clean-Up and Flowback Optimization Considering Emission Reductions
Authors: Theuveny B. , Rashid K. , Bailey W. , Hay G. , Gemmell D. , Comley R. 
Published: October 2023

Abstract
Ultimately, most new wells need to be put into production, whether it is for temporary well testing during the exploration and appraisal phase or during the development phase prior to commercial flows. This process, commonly known as clean-up, encompasses tasks such as handling contaminated fluids, ensuring proper disposal methods, and managing flow instability during the initial stages. These aspects pose various challenges that need to be addressed.
Regrettably, the conventional approach to fluid disposal has been through flaring. The primary concerns of cost efficiency and expediting commercial production have outweighed other considerations. However, some commendable local regulations, like the one currently in effect in Brazil or the Gulf of Mexico, have mandated the storage of liquid effluents during these operations. The driving force behind such mandates is primarily focused on reducing the visibility of fluid releases into the environment, rather than addressing the actual environmental impact. It is important to note that these "non-routine" flaring operations contribute to less than 5% of the total emission footprint and should not be overlooked. Based on an analysis of over 300 clean-up operations worldwide, we have concluded that it is feasible to reduce the required amount of flaring for well start-up and clean-up operations by 50%, without compromising the future performance of production systems.
The paper illustrates how a thorough assessment of field development architecture, operation scheduling, and overall emission footprint can result in a mutually beneficial solution for clean-up. Interestingly, and somewhat counterintuitively, we demonstrate that it is feasible to minimize the quantity of flared hydrocarbons through an intricate operational sequencing of clean-up operations. These seemingly improbable (and non-intuitive) operational sequences are made possible by implementing remotely controlled and automated choke sequences, coupled with real-time monitoring of well conditions.
Accurately measuring the potential reduction in emissions plays a crucial role in successfully implementing these innovative methodologies. The adoption of such approaches by regulators, operating companies, and service providers hinges on the combination of quantifiable environmental impact, operational reliability, safety, and economic considerations. This paper showcases the implementation of these processes in both land and deep-water operations, offering insightful comparisons between different options. The challenges associated with deployment are discussed, and practical lessons learned from the Middle East and deep-water operations are shared, demonstrating how emissions during clean-ups can be reduced by up to 50% while also lowering operational costs.
A Future Pathway for CO2 Geological Storage (CCS) in the Offshore Pre-Salt of Santos Basin
Authors: Pizarro Jorge O. S. , Branco Celso C. M. 
Published: October 2023

Abstract
Carbon Capture Utilization and Storage (CCUS) operations in the Pre-salt Santos basin oil fields should injected, by 2025, a total of 80 million tons of CO2, as additional production units enter operation. This stands as one of the largest CCUS projects in the world, since the CO2 originally dissolved in the oil is reinjected as an Enhanced Oil Recovery method. The infrastructure already placed in the Pre-salt, the characteristics of the reservoirs, the continuous technological advances and the acquired experience, allow us to glimpse a future scenario in which current CCUS operations will open opportunities for strict CCS (Carbon Capture and Storage) projects disposing of anthropogenic CO2. This paper aims to discuss the long-term perspectives for CCS projects in Brazil taking as a case study a hypothetical Pre-salt field, inspired on a real one, resulting in a preliminary estimate of CO2 storage capacity.
The text encompasses an overview of the CO2 sources in Brazil, a review of the main mechanisms of CO2 entrapment in porous media and a summary of the technical requirements for proper injection and permanent CO2 underground storage. Sound reasons may justify the future exhausted/depleted Pre-salt fields as a scenario for CCS projects: reservoirs with large storage and sealing capacity, good injectivity, presence of infrastructure of wells and pipelines (production units will probably need to be replaced in the long term), among others. We propose a workflow, based on material balance, to reach a preliminary estimate of the CO2 mass that could be stored in the field case study. The adopted procedure uses publicly available data and assumes parameters for total reservoir compressibility, reservoir pressure and CO2 water solubility in formation brine.
The exercise carried out for the case study, admitting the field at the end of its producing stage, pointed to a CO2 storage capacity of around 26 million tons trapped under the mechanisms of structural imprisonment in porous medium and dissolution of CO2 in brine. The obtained results highlight the vocation of the present Pre-salt oil fields as an important player for future CCS initiatives.
Preliminary Feasibility Study of an Ocean Thermal Energy Converter (OTEC) Platform for Offshore Brazil
Authors: Sales Joel Sena , Alho Alexandre Texeira , Souza Roberto Valente de , Fernandes Antonio Carlos 
Published: October 2023

Abstract
This study aims to identify the technical and operational challenges that impact the feasibility for the implementation of a 1MW (gross) Brazilian offshore Ocean Thermal Energy Conversion (OTEC) pilot plant. The OTEC technology utilizes the thermal gradient available between different layers (and depths) in the ocean to operate a heat engine to produce power output. It is expected to become mature enough to establish commercial power plants. The analysis is done by using coupled models in which ocean characteristics, the sizing of engineering apparatus and operational aspects of an OTEC plant are taken into account. A closed Rankine cycle with ammonia as the working fluid was considered for the plant. The Brazilian Blue Amazon is a geographic region defined along the Brazilian coast with a high potential for thermal gradient applications due to temperature gradients of more than 20 °C between sea surface and water depths of 600m z 1000 m throughout the year. This study focuses in such region, called CHT field, in Campos Basin. Campos Basin is an attractive location suitable for offshore floating OTEC plants in Blue Amazon that is also located near the Brazilian Offshore Oil fields. Because of this, a synergy may appear between Offshore Oil Production know-how and floating OTEC applications, since its clean and renewable energy source may also be used to Decarbonize FPSOs and other offshore structures. The available thermal power is analyzed in terms of an average annual estimated for the CHTfield, based on different thermal gradients. For each thermal gradient, the mass flows of sea Hot Water Pipe (HWP) and Cold Water Pipe (CWP), Working Fluid (WF), the pipe diameters, the WT, HWP and CWP pump capacities, and operational parameters of the offshore OTEC plant are calculated. One of the outcomes of this study is the possibility of analyzing greater operational capacities of offshore OTEC plants, such as 10 and 100 MW.
4D Geomechanical Analysis to Support Field Strategy on Production and Well Positioning in an Ultradeep-Water Reservoir
Authors: Macias J. , Pedroso C. A. , Pessoa T. F. 
Published: October 2023

Abstract
Fault reactivation due to reservoir depletion in normal faulting areas is well-documented in the technical literature. Ultra-deep water (1550m) combined with low overburden gradient impose additional operational and environmental constraints in fault-bounded reservoir developments. Under this scenario, an accurate assessment of fault reactivation potential is required. This paper presents the results of a risk assessment analysis for a deepwater offshore field located in the post-salt section of Santos Basin, Brazil.
The initial 1D geomechanical model of existing wells indicated a stress state close to the frictional limit. A 4D geomechanical (Finite Element) analysis was performed to gain understanding on the pre-production stress state at the reservoir scale and its variation with depletion, via a one-way coupling to the reservoir flow (simulation) model. Stresses were mapped to seven fault planes, over which three index-ratios were estimated (Sh_ratio, τ_ratio, OT_ratio), which were later transformed to a traffic-light type representation of the risk of reactivation.
Results show an overall stress-path trend towards a more stable condition inside the reservoir (away from the frictional limit) with increasing depletion. Some isolated points, however, show favorable conditions for faulting that should be avoided in future drilling campaigns. Regarding reservoir delimiting faults, a stable but close to the frictional limit condition was observed in all planes for the pre-production state of stresses. A tendency to more stability is expected with depletion, similar to the central reservoir’s response. Some fault planes show local patches with potential for reactivation following different time sequences. This analysis highlights the importance of considering the potential risk of a hydraulic communication between the reactivated patches and shallower zones where a low burial condition could facilitate the opening of the fault. The main uncertainties in the analysis are related to fault strength parameters and the accurate estimation of differential pressures across fault planes, both having a decisive impact on the risk assessment.
An accurate estimation of fault reactivation potential is of great relevance in well planning, construction of safe mud windows and in particular the definition of safe limits for injection/depletion pressures. The later have the potential to impact the production forecast and economy of the project.