bluuebunny/crossref_metadata_2025 huggingface dataset:
A Framework for Trustworthy Digital Twins Over their Lifecycle
Authors: Hansen O. H. , Jaiswal V.
Published: October 2023

Digital twins, replicating the physical assets they represent and working safely, effectively, and efficiently, can provide trustworthy results within well-defined limits and to a stated level of confidence. Capability and trustworthiness over time requires assurance processes and a methodology to assess and qualify the digital twin solutions. The purpose of a continuous assurance process is to ensure that the capabilities remain valid over time. A standard (DNV-RP-A204, 2023) for the qualification and assurance of digital twins has been developed and released recently. The framework in this standard was developed in close cooperation with the industry, including offshore floating and subsea facilities operators, and is currently being used across the energy sector by both technology vendors, engineering companies and operators.

The ability to execute a specified action or achieve a specified outcome, based on real time situational awareness and decision support, will define the capability level of the digital twin, moving from descriptive to predictive to automated. Digital twins are becoming more data-driven and digitalized and should be prepared for automated decision making.

The framework presented within the standard (DNV-RP-A204, 2023) addresses requirements to the functionality, technology integration, operations, the digital twin platform, including data quality and cyber security aspects, and requirements to the organization developing and operating digital twins. For each of these areas, clearly defined working and quality assurance processes and requirements have been defined and described.

Keeping a digital twin trustworthy and valid over time is a key challenge. The digital twin solutions need to be identified and managed as a key system, integrated in existing work processes, subjected to management of change processes, and continuously updated to accurately represent the physical asset at any time. All stakeholders need to implement tools and processes to monitor, assess and manage all relevant changes, which shall be verified.

This paper presents the philosophy and framework of the methodology from DNV-RP-A204 in the context of developing and operating a digital asset, as well as learnings from completed and ongoing projects.
Emulsion System with Nanoparticles for Selective and Reversible Water Shut-Off in Mature Sandstone Reservoirs Offshore
Authors: Sergeev V. , Abe M.
Published: October 2023

Results of laboratory research conducted in the framework of laboratory program developed jointly by a technology provider and an offshore oil-gas fields operator are presented in this paper. The laboratory program included optimal list of experiments for testing physical and technological properties of the physico-chemical water shut-off agent, resulting in a ready-for-pilot solution at minimum cost and time. The studied water shut-off agent is an emulsion system with nanoparticles (ESN), which is an inverse emulsion augmented by the synergy of natural and artificial surfactants with supercharged silicon dioxide nanoparticles. The ESN consists of three liquid components: sea water, diesel and nanoparticle-based surfactant. One of the main tasks of this research was to study such features of the ESN as selectivity of blocking impact to water-bearing zones and reversibility of blocking effect in the oil-bearing zones of sandstone reservoirs in the Lower Miocene (2950 psi and 91°C) and Late Oligocene (3900 psi and 107°C) hydrocarbon formations. As a basic requirement from the operator, the ESN had to be stable at the said reservoir conditions and compatible with reservoir and process fluids. Besides that, the operator wanted to confirm that the ESN is an easy-to-handle water shut-off agent in the offshore environment, meaning that it can be prepared with ordinary equipment available at the vessel, all components are liquids easily mixed to each other at ambient conditions and ready-to-use composition properties do not change in time within the operation offshore. Thus, the laboratory program was executed in three successive stages, divided based on the experiment conditions: ambient; pressure & temperature; modeled reservoir conditions. In result, the ESN performed as stable and compatible water shut-off agent and met all requirements of the operator. In the series of core floods, conducted on eight sandstone cores of different permeability and saturation, it was confirmed that the ESN selectively and fully blocks water-saturated cores, while the oil-saturated cores permeability decreased slightly with clear tendency to full recovery under the flow of hydrocarbons.
Digital Twin in Oil and Gas Equipment for Predictive Maintenance
Authors: Dehghan M.
Published: October 2023

Digital twins as a virtual model that is designed to reflect a physical system can improve the performance of electrical and mechanical components in industries. With digital twin technology, the industrial organization can be assumed in a way that they implement a sustainable solution with stability and predictability. By using MATLAB and Simulink, in this paper, a digital twin was demonstrated for Electro-Mechanical parts of the drilling for oil and gas industries. Hence, every single element of electrical and mechanical components was defined including the rotational parts separately, then by connecting those parts, the entire process in a closed-loop control system can be controlled. Having this digital twin, healthy data was generated for the situation that the system is working properly, as well as failure data that can be assigned for those components that are prone to wear and failure. Considering a fault in the digital twin in every specific part of the equipment, fault data was generated that can be used for data analysis and machine learning to find a Remaining Useful Life (RUL). To show how it is possible, in the next step, a digital twin for a triplex hydraulic pump that is crucial equipment in the oil and gas industries was investigated, then by having a simulation in healthy and faulty situations the required data were generated. Having data, an RUL was defined by implementing a data analysis and machine learning that can be implemented to have predictive maintenance for the system and it is shown how building a digital twin and having predictive maintenance for our system may boost productivity while decreasing unexpected downtime, which is costly and time-consuming.
The 3W Project and its Strategy to Foster the Development of Data-Driven Solutions for the Offshore Sector
Authors: Vargas R. E. V. , Pinto R. L. A.
Published: October 2023

This paper presents the 3W project and the strategy adopted in contrast to the classical buy and build approaches to develop a data-driven solution which can be used by oil companies to overcome their technological challenges. With this strategy, solutions are developed in a collaborative and symbiotic way with several types of players in the global community. Results so far obtained with 3W are promising, which justifies and motivates other similar projects to adopt the strategy proposed in this article.
Formation Evaluation Enhanced by Cloud-Based Platform – A Presalt Case Study Using Public Data
Authors: Bertolini. A. , Dantas M. , Baines V. C. , Bize-Forest N. , Mullins O. C.
Published: October 2023

The cloud-based formation evaluation platform aims to accelerate real-time subsurface domain insights and enable collaboration with domain experts during operations for faster and better decision-making. The proposed platform quickly creates a 3D near-wellbore reservoir model honoring geological trends that can be updated within minute-to-hours as new data are acquired and interpreted.

The cognitive E&P environment caters for real-time applications and near-real-time applications using PRISM and OSDU as their respective cloud architecture. The fast modelling is enabled by an innovative meshless smart structure algorithm that inputs the borehole geology interpretation to create an implicit function at the wellbore, which represents the geological trends, and populated with petrophysical properties using a combination of geostatistics and machine learning methods. The workspace and its content are available for visualization and download. The more complete the shared dataset, the higher the accuracy of the pre-job model.

The proposed cloud-based workflow provided a focal point for integration of all advanced well and seismic data streams presented in this paper and a stringent test for present-day reservoir realizations. The 3D contextualization of critical wellbore insights combining rock, fluid, and pressure enhances the real-time and near-real-time capabilities to properly evaluate different formations and productive reservoir intervals. Those capabilities accelerate real-time subsurface domain insights and enable collaboration with domain experts during downhole measurement operations for faster and better decision-making. Operational decisions and data acquisition programs need to be made in an operational timeframe, where derivatives from one or more sensors run may affect decisions for subsequent data acquisition runs in the well and future rig activities.

The case study was created with data from the public datasets published by National Petroleum Agency (ANP). Apart from drilling data such as mud-logs, logging while drilling logs, and deviation well surveys, the available wireline well datasets include high quality image logs, dynamic pressure measurement, downhole fluid scanning stations, and advanced petrophysical logs. The data integration of wells was interpreted with the surface seismic providing a connection among the presalt wells for a proper 3D near-wellbore modeling.

Data from different sources can now be consumed using the cloud-based wellbore measurement workflow. The coupling of dynamic and fluid data with the facies identification provides a means to incorporate fluid data into a geo-model at early stages of reservoir evaluation. The results of this integrated analysis can be potentially used to develop a geo-scenario, which is the sequence of major events that occurred in the reservoir, both rock and fluid, over geologic time.
Automated External Corrosion Detection for Process Equipment With Ai
Authors: Ferguson Eric L. , Potiris Steve , Castillo Marco , Dunne Toby F. , Bargoti Suchet , Kazzaz Ibrahim
Published: October 2023

Atmospheric corrosion poses the most significant threat to the integrity of offshore Oil and Gas (O&G) platforms in the Gulf of Mexico (GoM). Traditional manual inspection of topside equipment on these platforms is not only expensive, time-consuming, and labor-intensive but also subjective and incomplete, leading to an increased risk of unplanned shutdowns due to overlooked repairs. To address these challenges, computer vision and machine learning algorithms can be employed to detect and categorize corrosion accurately. This approach enables an objective and comprehensive management of corrosion throughout the facility. By identifying and reporting areas with detected corrosion, the system can prioritize high-risk equipment, which is prone to failure and can have severe consequences, for prompt remediation, thereby significantly reducing the likelihood of unplanned downtime. This paper introduces a pioneering AI-based system that revolutionizes corrosion management and inspection processes, specifically designed for offshore O&G platforms. The authors present a case study illustrating the application of this AI-based corrosion management system on a large GoM offshore platform. The practical impacts of this technology on corrosion management are demonstrated, showcasing how machine learning and computer vision algorithms vastly enhance inspection, maintenance, and overall management processes, ultimately leading to reduced operating costs and risks associated with offshore O&G platforms.
Mechanistic Analysis of Various Scale Inhibitors on Calcium Sulfate Precipitation
Authors: Alissa F. M. , Aljeaban N. A. , Tobon-Gonzalez J. , Albaiz A. I. , Alzahrani A. A.
Published: October 2023

The deposition of scales is one of the major challenges in the oil and gas industry. Prevention of such challenge is carried out using chemicals known as scale inhibitors. However, not all inhibitors function the same. For instance, some inhibitors function as threshold inhibitors, while others function as crystal modifiers. In order to investigate this, several experiments for precipitating Calcium Sulfate were carried out in the laboratory by mixing Calcium, and Sulfate brines. Following the precipitation process, the solid was filtered out using vacuum filtration. Subsequently, ion chromatography was used to determine the concentration of sulfate ions present in the solution. Herein, the inhibition efficiency of various phosphonic-acid based inhibitors: ATMP, PAPEMP, and BHMTMP were examined and compared against a baseline blank test. Afterward, the mechanism of inhibition was interpreted from the kinetic experiments. Generally, the performance of a threshold inhibitor tends to plateau. Both ATMP and BHMTMP reached a maximum inhibition efficiency of calcium sulfate precipitation around 30%. No significant change was noticed when increasing the concentrations to 300 ppm. On the other hand, the performance of PAPEMP was non-threshold reaching 53% inhibition efficiency at the same concentration.
Multi-Scale, Multi-Process and Multi-Issue Integrated Geological Modeling: A Solution for Brazilian Pre-Salt Reservoirs
Authors: Massonnat G. , Lesueur J. L.
Published: October 2023

In the field of geosciences for oil and gas, there is a disconcerting question that is not often tackled: could we correctly model and predict what might not have been understood? The answer seems natural and obvious. Therefore, the capability of a geological modeling workflow to meet the needs of correctly predicting reservoir petrophysical properties in the 3D space requires that the geological processes driving the current organization of these properties have been correctly identified and characterized prior to the modeling phase.

In the case of carbonate reservoirs, whether marine or lacustrine, the complexity of prediction is largely linked to the multiplicity of processes that have generated the heterogeneity of the reservoirs. Distributing in a reliable way the final properties resulting from geological history shaped both by different organizational logics and by dependence on successive heritages is an immense challenge with major technical and economic consequences. Claiming to go beyond it, as is often the case in industrial studies, despite a lack of concepts, techniques, tools or time, could appear as a lack of lucidity. But reservoir geologists are sometimes constrained by the "good enough" approach were a lack of global understanding and modelling is weighted with regards to a potential loss of revenues generated by miscalculations of reserves.

Nevertheless, reservoir modeling remains a crucial step in the reservoir appraisal process, especially when limited dynamic data is available. For several decades, this modeling has been based on the use of geostatistical techniques whose strength lies more in their ability to honor the available hard data than in the quality and reliability of extrapolation beyond the drilled zones. It is known that the use of these techniques does not allow the validation of the geological hypotheses underlying the stochastic simulations, and that multi-scenario approaches are usually lacking in the evaluation of reserves and resources attached to discoveries.
A New Method for Torque and Drag Retro-Analysis to Obtain Accuracy to Compute the Friction Factor for Wells in Severe Drilling Scenarios of Pre-Salt Fields
Authors: De Souza Marcio Francisco Alves , Dos Passos Adriano Gouveia Lima Gomes , Fernandes Fernando Bastos , De Lima Flank Melo , Britto Guilherme Augusto Santos , Buzza Joseph Eduardo Harbi , Portugal Luis Fernando Dunley , Soares Matheus Morato , Pereira Virgínio Augusto Moreira
Published: October 2023

New technologies and methodologies for estimating torque and drag (T&D) response during directional and horizontal drilling wells are constantly being researched in the literature. Classical methods developed in the 80s are still used nowadays. However, their approximations involved may incur significant errors during the well drilling design and operations. In contrast, using numerical methods may increase the computational costs of a well plan and result in unfeasible designs. A methodology to determine the friction factor based on retro-analysis of data from drilled wells is presented to support well design in severe drilling scenarios, such as the pre-salt of Brazil. The systematization of the T&D retro-analysis process makes it possible to compose a database and consequently allows to determine the friction factor more accurately, as well as the analysis of the variables' influence on it and results in more accurate decision-making on resource planning and well design, such as: use of power section in the BHA, drill string assembly, maximum casing extension, back-reaming operation, rig type choice and feasibility of wellbore completion. A case study of planning and design in Pre-salt of Brasil is presented, in which the wells have very deep final depths and/or challenging trajectories, the drill string and the rig are subjected to efforts that approximates their operational capacities, even when considering the best on the market. Therefore, in these scenarios, a high accuracy of the friction factors values, used in the design phase, is crucial for planning and execution success. The methodology to determine the friction factor based on retro-analysis of drilled well data results in more realistic and accurate friction factors.
Axisymmetric Displacements of Miscible Fluids in Annulars with Washouts for Applications in Primary Cementing Operations
Authors: Carvalho F. C. , Oliveira R. M. , Author D. E. , Author F. G.
Published: October 2023

Primary cementing is "the process of installing cement in the annulus between the casing and the formation exposed to the well", NELSON (1990). The cement provides permanent zonal isolation to prevent contamination or undesirable fluid migration toward the annulus. It protects the casing from corrosion and provides hydraulic and mechanical stability throughout the oil well productive life. During the drilling stage, irregularities in the cross-section, defined as washouts, can occur caused by partial collapses of the open hole section due to the presence of poorly consolidated rocks in the formation. A successful primary cementing operation will depend on whether the spacer fluid system and the cement slurry adequately and completely displace the drilling mud from the annulus and washouts. Motivated by this industrial problem, the present work performs a Direct Numerical Simulation of the vertical displacement between two miscible Newtonian fluids confined in eccentric annular spaces containing an expansion followed by a contraction. We investigate how different viscosities and densities of the injected and displaced fluids, the miscibility between them, the injection rate, and the dimension of the rectangular washout affect the two-phase flow, and calculate displacement efficiencies.

Our numerical algorithm was developed in C language using finite differences and spectral methods and solves the Navier-Stokes equations with variable viscosity in cylindrical coordinates coupled to an advection-diffusion equation for a scalar field that measures the concentration of the more viscous fluid.

Our results predict very high displacement efficiencies, close to 100%. Although the fluids used in industrial cementing processes are non-Newtonian, the high displacement efficiencies found in the current results motivate the use of spacer fluids as a strategy to control the interface properties. Thus, approximating the field conditions to the ones encountered in the displacement between miscible Newtonian fluids can lead to increases in displacement efficiency. Needless to say, this might have important consequences for the safety and integrity of oil wells.

We emphasize that the axisymmetric displacement between miscible Newtonian fluids leads to very high displacement efficiencies, close to 100%. The calculation of such efficiencies for miscible fluids considers the miscibility between them and is easily obtained from averaged values of the concentration parameter.
Catching Failures in 10 Minutes: An Approach to No Code, Fast Track, AI-Based Real Time Process Monitoring
Authors: Anzai T. K. , Furtado P. H. T. , de Brito G. M. , Santos J. S. , Moreira P. C. M. , Diehl F. C. , Ferreira L. E. L. , Grava W. M.
Published: October 2023

Process monitoring has gained significant attention in recent years due to the need for certain industry sectors to enhance their processes' performance and safety. This development has enabled, more than ever, novel applications in real industrial systems. However, the desire to achieve quick results has led to decentralized and unstable applications that can hinder the long-term scalability and maintenance of these technologies. Moreover, the proliferation of commercial tools in response to the industry's demand for digital transformation has made selecting the right solution a daunting task. To address these challenges, Petrobras developed the SmartMonitor platform. SmartMonitor empowers users to create and configure, usually within minutes, online machine learning and first-principles monitoring tasks using a user-friendly, no-code visual programming framework. This approach ensures accessibility and democratizes the process of task creation and management. Additionally, the platform supports the inclusion of new methodologies and monitoring techniques, making it an integrated development hub aligned with best practices in machine learning models management. Currently, SmartMonitor has hundreds of tasks running in real-time, generating performance indices on critical equipment in Petrobras units. This paper provides a description of some of these tasks, along with an overview of the SmartMonitor platform's structure, its monitoring philosophy and challenges regarding process monitoring in real industrial systems.
Application of Automatic Wellhead Displacement Monitoring System by Computer Vision in Offshore Well
Authors: Teixeira G. T. , Weidlich M. C. , de Souza C. O. , Dias R. , Pestana R. G.
Published: October 2023

This work presents the application of an automatic wellhead displacement monitoring system in offshore wells. The system uses computer vision algorithms applied to ROV videos for estimation of wellhead motion. Obtained results are then compared to BOP (Blowout Preventer) accelerometer data.

The system identifies and quantifies, through tracking algorithms applied to ROV videos, the horizontal and vertical displacement time series of the wellhead. Subsequently, it provides quantitative data suitable for use in a wellhead fatigue analysis and preliminary risk assessment of wells where wellhead motion is observed during ROV inspection.

The results of the analysis of an offshore wellhead displacement using the developed tool are presented, as well as the comparison of this outcome with data from BOP sensors. The results were used both to quantify the criticality of the displacements and to calibrate the soil models (p-y curves) used in global riser analysis.

Comparative investigations show good agreement with BOP accelerometer data.

The novelty of the tool is to automatically quantify the horizontal and vertical displacement of the wellhead using computer vision in ROV videos.

Preliminary results show that the use of computer vision techniques can bring improvements to the analysis process, providing a tool for calibration of numeric models used in well integrity assessments, especially in situations where accelerometer data is not readily available.
Decision Tree Regression Method Applied in Well Clustering: A Supervised Approach
Authors: Vianna I. G. P. , Valladares I. F. , Pacheco C. E. P. , Brito A. C. de A. , Costa F. R. , Mendes D. H.
Published: October 2023

Drilling rigs are an expensive resource in the oil and gas industry; hence, planning their time properly is necessary. Estimating activity durations plays a crucial role in the rigs' planning. The selection of correlated wells to be used in estimation models is vital for good duration estimative. Based on this necessity, we present a regression supervised method to cluster wells. Results were compared with traditional unsupervised clustering methods.

The developed method transforms a machine learning unsupervised problem (without a target) into a machine learning regression supervised problem (with a target). We use a decision tree regression to transform an unsupervised clustering problem into a supervised clustering problem and compare it with the other two methods based on K-means (unsupervised). We apply multiple linear regression with leave-one-out cross-validation in the resulting clusters to evaluate the clusters.

We tested the methodology in eight different scenarios, varying in number of wells (42 to 236) and similarities. All scenarios were based on real wells from a large Brazilian energy company. The target for the decision tree regression methodology was the drilling duration, and the variables were water depth and well footage. We limited the minimum number of wells per cluster, reducing overfitting in the estimation technique. Our methodology reached the lowest mean absolute percentage error value for all scenarios. The decision tree regression methodology can increase the capability of the expert to select similar wells based on their characteristics and duration.

The novelty of the decision tree regression method applied in a clustering problem is to provide the experts with a tool that considers the operational duration, besides the traditional set of relevant variables, transforming an unsupervised problem into a regression supervised problem. With the decision tree regression method, it is possible to cluster wells in more similar groups, improving any further analysis.
Implementation of Magneto-Rheological (MR) Elastomer for Mitigating Fishtailing Instability in FPSO-Tanker In-Tandem System
Authors: Zainuddin M. , Kim M. , BhatAramanadka S.
Published: October 2023

The objective of this study is to analyze the implementation of MR Elastomer (MRE) Tensioner system in FPSO-Shuttle Tanker in-tandem system to mitigate fishtailing instability. It is also to identify the opportunity for digital twin implementation for similar application.

Fishtailing instability in the FPSO-Shuttle Tanker in-tandem system, and the implementation of MRE Tensioner in this system are analyzed by performing mooring-vessel-coupled time-domain analysis utilizing Texas A&M in-house CHARM3D program. Two types of FPSO are considered, which are turret FPSO and spreadmoor FPSO. West Africa metocean condition is used in the simulation as this region contains significant number of FPSO. First, two-body frequency-domain WAMIT simulation is performed to obtain the required vessel hydrodynamic data. These data, together with mooring, riser and hawser data are inputted into time-domain analysis (CHARM3D). The MRE Tensioner is modelled in CHARM3D and it is based on the physical MR Elastomer and Elastomer Tensioner system. The MRE Tensioner is then used as hawser connection on FPSO side. A simulation of FPSO-Shuttle Tanker with fishtailing instability is performed and used as baseline (called Fairlead case). Hawser angle, which is the angle the hawser deflects due to out-of-phase sway and yaw motions between the FPSO and Shuttle Tanker, is calculated in the post-simulation to measure the severity of fishtailing instability. Two MRE Tensioner cases for each FPSO type are simulated to investigate the stiffness level required to suppress fishtailing instability. The first MRE Tensioner corresponds to the 0A energizing current, which corresponds to the lowest MRE Tensioner stiffness. The second MRE Tensioner corresponds to the current level to get the appropriate MRE Tensioner stiffness that results in significant fishtailing suppression.

The Fairlead case exhibits significant hawser angle dynamics indicating fishtailing instability in both turret FPSO-Shuttle Tanker case and spreadmoor FPSO-Shuttle Tanker case. However, spreadmoor FPSO-Shuttle Tanker case exhibits benign motion than turret FPSO-Shuttle Tanker case. In MRE Tensioner cases, no significant improvement is observed in MRE Tensioner case with 0A energizing current or with the lowest tensioner stiffness. Significant suppression is observed when 5A energizing current is implemented in turret FPSO-Shuttle Tanker case. Fishtailing dampening is also observed when 10A energizing current is implemented in spreadmoor FPSO-Shuttle Tanker case.

The novelty of MRE Tensioner is its ability to adjust its stiffness which enables it to be utilized as means to suppress fishtailing instability for a given metocean condition by utilizing it as hawser connection. This in turn provides an opportunity to improve hydrocarbon offloading uptime. Furthermore, having the ability to control hawser connection stiffness through electrical current signal provides an opportunity for digital twin implementation.
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

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

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

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

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

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

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

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.