bluuebunny/crossref_metadata_2025_split huggingface dataset:
Calculation Methodology to Evaluate Casing Design in ROV-Drilled Relief Hole Scenarios
Authors: Ferrarezi L. N. , Valore F. , M. dos Santos C. , Moreira N. 
Published: October 2023

Abstract
A cascade casing collapse occurred in a well in the Santos Basin was caused by the thermal transient effect, as discussed on Moreira Jr. et al, 2019, leading to operational restrictions that might be mitigated by using ROV-drilled holes near the wellhead. This paper proposes a simplified conservative methodology to calculate structural loads in wells considering the annuli communication by ROV intervention. Hence the objective is to assess technical viability, as regards well integrity, aiming life extension of susceptible wells. A practical and simplified analysis method was sought using the WellcatTM thermal-structural simulator, due to a potential large number of wells to be evaluated. Steady-state loads were selected that conservatively represent the transient analysis for the initial moments of injection (using high flow and low injection temperature) in the four main proposed scenarios: ROV-drilled relief hole in surface casing, relief holes in surface and intermediate casings, relief holes in surface and intermediate casings plugging the surface casing at geothermal temperature, and relief holes in surface and intermediate casings, plugging the surface casing afterwards while injecting at cold temperature. It was possible to successfully apply the simplified casing design structural analysis method in five injection wells at Santos Basin pre-salt so far. It was possible to state that the adopted conservative simplifications did not make the operation of the wells unfeasible, since all of them were approved without restrictions in at least two of the four main evaluation scenarios. In two of the injection wells, the study brought the restriction to manage annulus pressure. In another well, due to a less resistant surface casing, plugging the surface casing was only approved if done at cold injection, because it would bring a casing cascade collapse threat if the plugging operation was done at a higher temperature (geothermal). It is also important to state that this ROV-drilled relief hole technology also requires attention concerning the type of mud on the trapped annulus (as synthetic mud must be recovered if not plugged to avoid pollution) and non-identified failures on the cement that are acting as a well safety barrier. Besides, the scenario of not plugging the surface casing may incur in external corrosion of intermediate and production casing strings. This work presents a new methodology for casing design applied to wells with ROV-drilled holes and brings example cases where the method was successfully used. Before, this technique was seen as viable, but there was no formal method to evaluate casing integrity in this condition. It is an enabling solution for injection wells where transient analysis indicates the possibility of cascade collapse failure, and a ROV drilling campaign is already being based on the proposed method.
New Technique to Plug and Abandon Intelligent Well Completions with Flat Packs
Authors: Scott Martin Schoener , Bazan Pedro Henrique Garcia , Neto Jose Salles Rosa , Pagung Alison , Botinha Bruno Rodrigues , Tazaïrt Réda , Ceccon João Paulo Faria 
Published: October 2023

Abstract
The scope of this abstract is to highlight the complexities that arise when attempting to plug and abandon (P&A) smart well completions. Just about every well that has a smart completion design includes flat pack equipment. Flat packs are commonly used when several different lines are terminated at approximately the same depth in the well. Common applications include intelligent well systems, deep-set chemical injection lines with downhole gauge cable and safety valve lines with shallow set chemical injection lines.
As part of the complex P&A operation the upper completion of the well must be retrieved. To retrieve the upper completion, the production tubing and the flat pack must be cut or severed completely. If the cut is partial there is a high probability of losing complete sections of control line and associated debris in the well bore. This debris can potentially negate the possibility of providing a clean and secure well abandonment, not to mention the high cost of non-productive time (NPT) due to fishing operations to remove the debris.
Two System Integration Tests (SIT) were completed to prove the concept of cutting through pipe and a flat pack within a single operation, one with a 5 ½″ 23ppf S13Cr 95ksi pipe inside of a 10 ¾″ casing and the second was with a 6 5/8″ 28ppf S13Cr 95ksi inside 10 ¾″ casing. Prior to inserting the 5 ½″ pipe into the casing, a flat pack was strapped to the external wall of the pipe. A section of the casing wall was cut out to install an acrylic window to visualize the cutting operation and evaluate its effectiveness. The cutting tool was inserted into the tubing and placed in position to make the cut of the pipe and the flat pack with control lines. The cutting process took approximately 2 hours for both tubing sizes. The tool was able to successfully cut the tubing and the flat pack in two tests. Based on these results, the solution was deployed on an actual operation in 2021 with excellent results described in this paper.
This cutter technology can be used for other size tubing and casing combinations. The time it takes to make the cut is considerably less than having to clean up the well bore after attempting to retrieve the upper completion using other less effective cutting methods. This cutter technology can make multiple cuts in a single run, and it can also be used to cut multiple casings. No explosive or chemicals are used to make the cut.
Data-Driven Workflow for Categorization of Brines Applied to a Pre-Salt Field
Authors: Fernandes M. A. , Gildin E. , Sampaio M. A. 
Published: October 2023

Abstract
In this work we propose a pure data-driven framework to categorize oil producing wells from a pre-salt field based on the chemical compositions of the original formation water, without depending on physical-chemical equations or simulation models. Our unsupervised learning method is intended to group wells with similar reactivities, which could require the same management actions. Taking as a starting point some formation water composition analyses, mostly sampled from injectors, our first step is to spatially interpolate the concentrations of each of the ions, resulting in maps that can give us estimates of the values in the vicinity of the producing wells. Then, we apply dimensionality reduction methods, as the Principal Component Analysis (PCA) to get a clearer view of how those wells are distributed in terms of water composition, and if any kind of grouping is possible. We then use the clustering methods K-means, Fuzzy K-means and Self-Organizing Maps (SOM) for the last step in knowledge extraction. The work focuses on an exploratory analysis to detect trends and groupings of wells with similar characteristics. Observing which wells are contained in each group is therefore useful to drive our efforts in actions such as the correct application of scale inhibitors both in the reservoir and in the production tubing; dimensioning the sampling frequency of produced water for analysis of chemical composition and inspection of solids; validation or adjustment of the injection strategy, considering the compatibility of the injection water with each group's formation water and the consequences of their mixture. The novelty presented is how we are extracting knowledge from the available data (scarce history of breakthroughs, but with an abundance of laboratory analysis) and using it as a decision support tool in the management of pre-salt carbonate reservoirs.
Application of High-Definition Borehole Imaging-While-Drilling Technologies in Presalt Carbonates of Brazil
Authors: Laier A. P. C. C. , Silvestre A. P. , Rosa A. P. , Fernandes P. P. , Ferraz E. K. P. , Cuadros G. M. 
Published: October 2023

Abstract
Borehole images play a crucial role in understanding the depositional environment and diagenetic processes that govern fluid flow in Brazil's presalt carbonate reservoirs. Acoustic and resistivity image logs offer superior resolution compared to the other types of measurements normally acquired for reservoir characterization using either logging-while-drilling (LWD) or wireline technologies. Advanced formation evaluation techniques can be employed to characterize the reservoir, optimize drilling operations, and design completion strategies by combining image logs with additional borehole data. Traditionally, the analysis relied on wireline conveyance technologies, primarily due to the challenges of integrating high-resolution sensors into logging-while-drilling tools capable of capturing detailed images in harsh drilling conditions.
Petrobras recently adopted two high-resolution LWD borehole imaging systems for Brazilian offshore operations. One of these systems offers high-resolution acoustic images suitable for all types of drilling mud, along with apparent resistivity images specifically designed for oil-based mud. The second technology deployed is a laterolog-type system that acquires borehole images with water-based mud. This implementation enables high-resolution borehole imaging while drilling for all mud types, closing a previous technical gap between LWD and wireline technologies. Both technologies use a unique feature-based data compression method to transmit the images in real time.
In deepwater operations, acquiring high-definition LWD images can be compromised by heave-induced errors in the depth measurement taken as a reference, currently provided by the rig. To address this, heave-filtering workflows are applied to preserve the integrity of subsurface features. Processing of the time-indexed data using this application yielded positive results, instilling confidence in the capabilities of these technologies.
Examples from five wells drilled in presalt carbonate reservoirs are used in this document to present and support the first experiences and learning curve using these LWD imaging technologies in Petrobras offshore operation to enhance reservoir characterization.
A New Approach in the Performance of Sorption Booms in the Removal and Recovery of Oil Spills
Authors: Zaldivar M. Paredes , Lima M. S. , Queiroz G. P. , Martins W. , Mulinari D. R. , Faria G. V. 
Published: October 2023

Abstract
This work aims to compare the performance of sorption booms used to remove and recover oil spills. The first type of sorption booms was filled with eco-friendly polyurethane - natural palm fiber composite, and the others were filled with recycled polyurethane. In addition, the oil recovery and reusability of booms were studied. The study was done with mini-sorption booms and real-scale booms. The sorbent foam of eco-friendly polyurethane composite was obtained by partially replacing petrochemical monomers with polyols derived from vegetable oils and adding natural palm fiber residues. On the other hand, the sorbent foam of recycled polyurethane was obtained with petrochemical monomers. The tests were carried out using mini and real-scale sorption booms with 0.3 and 3 meters of length, respectively. The oil sorption capacity and the recovery efficiency in oil and water/oil systems were studied. Also, the oil recovery and boom reusability were tested. The study revealed that booms with the eco-friendly composite polyurethane as filling exhibited higher efficiency in oil sorption capacity with all the oil types, reaching values about two times higher than with the recycled polyurethane filling. However, the material-fabric integration still needs to be studied, which could affect the final performances. In the case of the oil recovery efficiency in water, the tests exposed the best performance of the first boom type, which absorbed almost 100% of the oil in less time and maintained its buoyancy. Also, the boom oil recovery efficiency values were between 50 - 80 % during the reuse of up to seven cycles compared with values of about 40 % for polyurethane booms. Then, the sorption booms filled with eco-friendly polyurethane composite foams are highly efficient in removing and recovering oil spills, being better than booms filled with recycled polyurethane. This study presented a new experience not previously published, revealing the highly efficient performance of sorption booms filled with eco-friendly polyurethane composite. The efficiency of the composite material used as sorbent filled was previously certified by the Centre of Documentation, Research, and Experimentation on accidental water pollution (CEDRE) in France.
Carbonate Re-Stimulation in an Offshore Well in Brazil Pre-Salt Using a New Single-Phase, Polymer-Free Delayed Acid System
Authors: Lai B. , Zakaria A. , Cruz V. , Riolfo L. , Junior A. , Monberg J. , Puyaubran J. L. , Hernanadez J. , Wiratnanto B. , Mohamed M. , Lacerda L.A. 
Published: October 2023

Abstract
The paper highlights the successful application of a new single-phase, polymer-free delayed acid fluid technology for re-stimulation in an offshore well in Brazil's pre-salt field. The study's objective was to evaluate the effectiveness of this new system in bypassing near wellbore formation damage and to compare it with the conventional emulsified acid system.
The new fluid system underwent extensive lab testing in Houston and Macaé with the support of TotalEnergies Reservoir Wellbore Interface (RWI) in Centre Scientifique et Technique Jean Féger (CSTJF) before being utilized for the re-stimulation job. Propriety matrix acidizing software was employed to optimize the job design, volumes, pumping rates, and diversion strategy. The treatment design aimed to ensure acid coverage along the wellbore of a multizone well and radial extension to bypass formation damage. The treatment was verified by pre-treatment and post-treatment production logging tool (PLT) analysis. Prior to the main acid pumping, an acid prewash with coiled tubing equipped with a pulsating pressure waves tool was performed. The acid pumping plant was arranged on a modified platform supply vessel (PSV), which significantly reduced the costs involved with a dedicated Stim Vessel. The treatment was performed successfully utilizing modified PSV) via a drillship to the subsea well. The acid pumping plant arranged on PSV was a unique project, where a full Stimulation Plant was assembled on the main deck of the support vessel, significantly reducing the costs involved with a dedicated Stimulation Vessel.
The new single-phase, polymer-free delayed acid fluid technology resulted in an overall skin reduction from -0.8 to -4.0, despite the variations in permeability observed in different zones. The system was successful in treating all three zones as planned, leading to an incremental production increase of 17% on barrels of oil per day (bopd) after well production stabilization and an increase in production index (PI). The effectiveness of the system was confirmed by Production Logging Tool (PLT) analysis before and after the treatment. Using the new acid fluid simplified operations compared to the emulsified acid system used previously in the initial stimulation, reducing rig time for the job execution. The new single-phase, polymer-free delayed acid fluid technology is considered a suitable candidate for treating multiple zones with permeability variations in Brazil's pre-salt formations.
The new acid fluid technology is an efficient alternative to the conventional emulsified acid system, which is logistically more complex and less environmentally friendly. The results of this study provide practical guidance for practicing engineers working on re-stimulation operations in offshore wells with near wellbore formation damage.
Unlocking Next Generation Well Construction Through Smart and Intelligent Tubular Running Process: Successful Application of Digitalization, Personnel Reduction, and Promoting Safety
Authors: Mahmood A. , Smith L. E. , Thibodeaux R. , Angelle J. , Brown Dougal 
Published: October 2023

Abstract
Well Construction is one of the critical phases during which drilling is planned for tubular running, casing, and completions operation. Historically a labor-intensive and manual-operation process and the associated hazards, risks, and challenges are still faced nowadays adding complexity to meet the desired operational metrics; in addition to championing safety and maintaining full competency and operational compliance. The petroleum industry is also leaning towards a cleaner energy transition that gives rise to transforming legacy systems and solutions to improve the overall economy. The advancements in digital solutions have helped to gain traction in various phases of the well, such as Drilling and Evaluation, Intervention, Production, and Abandonment, however, Well Construction has still yet to unlock comprehensive benefits for increased operational efficiency, flawless execution, reduced personnel – all while complying with current industry specifications and safety standards. To achieve the overall well objectives, a tiered-based digital solution is offered in Well Construction which not only incorporates digitalization and energy transition, but the true proof of industry values is also validated, providing solutions based on various rig types and setups.
With a detailed digital roadmap strategy and recognizing key features and added value, a series of field runs and deployments showed remarkable results capturing the safety metrics, operational cost reduction, and improved efficiency with the tiered approach in Well Construction. Based on various offered solutions, operational safety was improved between 41% to 70%, rig time savings, and efficiency improved between 16% to 33%, and the personnel reduction advocating digital technologies witnessed a larger range from 22% to 77% reduction in operational personnel. Regarding energy transition utilizing remote operations and an intelligent and autonomous tubular connection technology, the solution also offered about $1.9 million in annual cost savings with carbon emission reductions. The digital solution can be integrated based on rig requirements; hence various levels of this tiered technology can be combined to enhance the operational key performance indicators (KPIs). With advancements in digitalization, the power of data management, analytics, and visualization can improve operational metrics and highlight stronger financials with achieved targets. This paper will provide a comprehensive summary of a multiple-level award-winning offered solution, that promotes smart and intelligent Well Construction with validation of proof of value with numerous case studies witnessed in tubular running operations and beyond.
Recurrence of Cryptogenic (ESUS) Strokes in the First Year: Predictors and Outcome—A South Indian Study
Authors: George Jithin , Sylaja P. N. , Sreedharan Sapna E. 
Published: October 2023

Introduction:
Around 9–25% of ischemic strokes are embolic stroke of undetermined source (ESUS) with an annual recurrence risk of 4.5–5%. Regarding ESUS, studies from India are limited. Here, we studied the prevalence of cryptogenic ESUS among stroke subtypes, recurrence risk and outcome at 1 year, and their predictors.

Materials and Methods:
We performed a single-center study of ambispective nature. Patients above 18 years of age with a diagnosis of cryptogenic (ESUS) strokes from January 1, 2017, to December 31, 2020 (4 years), with a 1-year follow-up were recruited in our study. All the patients underwent neuroimaging computerised tomography/magnetic resonance tomography (CT/MRI) with angiography, electrocardiogram (ECG), transthoracic echo (TTE), and rhythm monitoring. Functional outcome was measured using the modified Rankin scale with scores 0–2 taken as good outcome.

Results:
We had 234 (11.21% of total ischemic strokes) subjects satisfying the criteria for ESUS over the study period with a mean age of 58.2 ± 12.8 years. 46 patients had a history of stroke/transient ischemic attack (TIA) at admission. 9.4% had a recurrent event at 1 year. The most important neuroimaging predictor of recurrent strokes was multiple embolic followed by superficial watershed pattern. Around 10% had more than one marker of atrial cardiopathy positive. While the risk factors, coronary artery disease (CAD), and neuroimaging pattern showed an association with recurrent events at 1 year on bivariate analysis, only the latter two remained significant on multivariate analysis.

Conclusions:
Our cohort of ESUS had a higher annual recurrence risk than reported before. Though vascular risk factors and ipsilateral vessel abnormalities were more in the recurrent ESUS group, it did not significantly affect the recurrence risk at 1 year. CAD and multiple embolic patterns on imaging showed an association with recurrent strokes, suggesting a possible cardiac substrate in our ESUS population as well.
Effect of Coronavirus Disease 2019 Lockdown on Eating Habits and Lifestyle Behavior
Authors: Karavadi Vidusha , Ganesh Kanumalee Pruthvi , Nair Naveen Sukumaran , Rao Sudhir 
Published: October 2023

Background and Aim:
The outbreak of coronavirus disease 2019 (COVID-19) affected the lives of all sections of society, as people were asked to self-quarantine in their homes to prevent the spread of the virus. The confinement and lockdown caused many lifestyle changes for Indian citizens, especially with diet and physical activity. The aim of the study was to assess the effect of COVID-19 lockdown on the dietary pattern and lifestyle behaviors in India.

Materials and Methods:
An online survey was conducted from July 2021 to September 2021 using a validated semi-structured questionnaire. The “snowball sampling” procedure was used to recruit the participants. The questions focused on changes experienced by the participants in their lifestyle before and during the lockdown.

Results:
Among the 624 study participants, the mean age was 25.81 ± 9.7 years. Nearly 71.8% (448) reported that their diet and consumption patterns changed during the lockdown. The mean body mass index before the lockdown was 24.11 ± 4.43, and after the lockdown was 23.46 ± 4.51. The change in sleep duration was reported by 494 (79.1%).

Conclusion:
These unprecedented circumstances provide an opportunity to better understand the negative impact of strict lockdown measures on lifestyles, and at the same time, help identify and initiate positive behavioral changes, which if consolidated, may improve chronic disease outcomes in the long run.