bluuebunny/crossref_metadata_2025_split huggingface dataset:
Revisiting Post-Blowout Wellbore Integrity: Mechanistic Modeling of the Stress Evolutions Within the Casing-Cement Sheath-Rock Formation System
Authors: Khan Jawad Ali , Khouissat Abdelhakim , Michael Andreas 
Published: February 2024

Abstract
Eleven ("10 + 1") mechanisms of mechanical degradation that can compromise the wellbore integrity are evaluated by modeling the stress evolutions within the casing-cement sheath-rock formation (C/CS/RF) system. Past attempts from the published literature overlooked the need for establishing an initial stress state that yields stability following cement setting (wait-on-cement). A novel approach is used to calibrate for the initial stress distributions assuming effective-radial-stress-and-displacement continuity along the CS's interfaces with the steel casing and the adjacent-RF.
Established analytical expressions form what is generally recognized as the basic stress analysis inside the casing walls and the RF region adjacent to a well. A calibration procedure is necessary to extend the stress model into the CS layer between the casing and the adjacent-RF considering effective-radial-stress-and-displacement continuity. Our mechanistic model is capable of evaluating against four failure mechanisms in the casing layer considering collapse, burst, tensile, and/or compressive stress loads, four failure mechanisms in the CS layer (inner or outer debonding, radial cracking, disking, and shear cracking), along with longitudinal and transverse tensile/"Mode I" fracture initiation in the RF layer (an "underground blowout"), and finally potential reactivation via shear-slippage of natural, pre-existing faults at close proximity, that could trigger seismic events.
Post-blowout-reservoir depletion, followed by pressurization after successful capping stack shut-in presents one of the biggest challenges vis-à-vis wellbore integrity. A case study is presented, assessing the wellbore integrity during the aftermath of the MC 252-1 "Macondo Well" blowout from April 20, 2010, in the deepwater Gulf of Mexico (GoM). The results differ from those of previous studies and we think are more realistic due to the improved approach used for calibrating for the initial stress distributions. Wellbore integrity is maintained during the heavy-pressure depletion that the reservoir experienced throughout the 86.2-day post-blowout-discharge period and the subsequent wellbore-pressure buildup that followed the successful well capping.
Meeting Increasing Demands for Upstream GHG Reporting – A Framework for the Drilling Industry
Authors: Emborg M. , Olsen S. I. 
Published: February 2024

Abstract
This paper details the scope and framework applied for quantifying upstream Greenhouse Gas (GHG) emissions linked to offshore drilling operations. A step-by-step methodological approach is presented, comprising environmental impact modelling of drilling and rig operational activities through application of the life cycle assessment (LCA) methodology. The method aims to break down upstream emissions to a process level, showing that emissions can be evaluated to a greater detail level compared to what current scope 3 reporting levels offer today. Results from a North Sea drilling case study conducted in collaboration with Noble Corporation are used for showcasing the impact burden levels, challenges and prosperity of accounting, reporting, and tracking upstream emissions as a drilling contractor. A framework tailored to the drilling industry is presented, emphasizing how upstream emissions may be linked to drilling and rig operational processes, and how these emissions can be continuously reported and improved over time. A set of system boundaries for assessing scope 3 emissions are suggested, along with recommended emission calculation methods. The presented framework may serve as an alternate supplement to IPIECA's adapted version of the GHG Protocol's Scope 3 Standard, otherwise intended for the petroleum industry, and to IADC's industry guideline for ESG reporting.
Dynamic Simulation of Riser Gas Handling with a Fixed-Choke Constant Outflow
Authors: Yuan Zhaoguang , Liu Yaxin , Zhou Lei , Hashemian Yahya 
Published: February 2024

Abstract
It is challenging to optimize operation procedures that safely remove riser gas without causing equipment, personnel, or unnecessary environmental issues. This paper presents results from studies of various scenarios using a fixed-choke constant outflow (FCCO) method that will keep the choke opening constant to measure fluid outflow while circulating the riser gas out through the booster line.
A commercial dynamic multiphase flow software program was used to study extreme scenarios of up to 300 bbl of gas influx in the bottom of the riser of a deepwater rig equipped with a riser gas handling system or managed pressure drilling (MPD) system drilling in 12,000 ft of water. The consequences of gas migration and free gas dissolution into both water-based and oil-based mud were studied. The initial fixed-choke opening was selected by modeling a 500-gal/min flow rate through the boost line with a choke sized to initially obtain from 150 to 200 psi surface back pressure. The pump rate was reduced to 200 gal/min or even 0 gal/min as needed to keep choke pressure; hence, the return flow rate is relatively equal to the initial target value. Other scenarios with different influx volumes and choke openings were also studied to check pressure consequences to the riser system.
When using the FCCO method to manage the 300 bbl influx with water-based mud, the software calculated a maximum pressure of 580 psi on the riser top. When using oil-based mud, a maximum pressure of 1,112 psi was observed on the riser top for the same scenario. When the same situation was simply shut in (instead of being circulated using the FCCO method), there was a maximum pressure of 2,300 psi on the riser top with water-based mud, but only 1,254 psi when using oil-based mud, ignoring for the moment the benefit provided by pressure relief valves in an actual operation, which could intervene before the riser top pressure reaches 2,300 psi.
The analysis of the resulting surface choke pressure and surface gas/liquid flow rate support the concept that circulation of the gas influx while adjusting pump rate to keep the flow rate constant through a choke at the fixed position (even if it means reducing the pump rate to 0 gal/min as flow is driven by gas expansion alone) would be easier to handle than by using other proposed riser gas management procedures.
This paper presents the first study of riser gas handling in an oil-based mud scenario considering gas dissolution with an FCCO and provide references for International Association of Drilling Contractors (IADC) riser-gas handling guidelines and deepwater well control guidelines.
Speech Recognition Technology Used to Detect Drillstring Breakover and Optimize Drilling Tasks
Authors: Groh A. , Kaya M. E. , Dunbar D. 
Published: February 2024

Abstract
Detecting when the entirety of a drillstring is moving—referred to as breakover—is necessary for automating several tasks in the drilling process. This paper provides an overview of how cross-industry application of machine learning (ML) technology helped solve challenges related to real-time pattern recognition of breakover and how this solution assisted with providing immediate metrics and control of the drilling process.
This project leveraged Hidden Markov Models (HMMs), used frequently in other industries for speech recognition and pattern recognition over time series data, to create a statistical classifier that detects drillstring breakover in real time. Although these techniques have not seen widespread adoption in the oil and gas industry, they provide a flexible solution to many automation problems. Model features correlated with string stiffness were constructed that allowed for accurate classification of pre-breakover and post-breakover states. Subject matter experts were enlisted to label 500+ examples of breakover, which were used to train and test models for both ascending and descending drillstrings. The models were then deployed and integrated into the drilling control system to provide monitoring capabilities and control certain processes.
The models provided accurate detections of breakover more than 90% of the time when measured against several wells studied for this project and provided hookload values for both breakover and general pickup and slackoff operations. This high accuracy allows for broad application of the model to several use cases. Applications include reducing an operator's 20-ft standard pickup distance, thereby reducing overall connection times, and using the associated models improved the quality of tares in deep lateral sections. The model also provided additional benefits, including automated drag monitoring for rotary drilling and tripping as well as hole condition monitoring during cleanup cycles. Both offer opportunities to optimize flat time and will be discussed in detail.
Thermal Effects on Drilling Performance in Hot Dry Rock
Authors: Vetsak A. , Gerbaud L. , Shor R. J. , Rogers A. , Jordaan W. , Toews M. 
Published: February 2024

ABSTRACT
High-temperature geothermal resources away from tectonic boundaries or geologic hotspots can be accessed by the drilling of deep wells through significant sections of basement rock. This paper evaluates the impact of rapid cooling on rock cutting process, and incorporates this effect as a part of potential drilling performance optimization.
Using data from a series of experiments conducted in a high pressure and high temperature (HPHT) drilling laboratory, we demonstrated that rapid cooling enhanced rates of penetration over 60% in the 300+ °C hot dry rock utilizing a PDC bit or a roller cone bit. Drilling was performed in hard igneous rock samples, with the unconfined compressive strength over 200 MPa. Each sample was heated and confined to predetermined conditions, then drilled with controlled parameters. The drilling performance data was acquired for each experiment, complemented with dynamic in-situ temperature measurements, and visual assessment of rock samples before and after drilling. The rapid cooling effect on the rate of penetration was found to be a function of the temperature difference between the drilling fluid at the bit face and the rock sample temperatures.
Unlike previous studies on the Drilling Performance, which overlooked thermal effects, our research focuses on the synergy between rapid cooling and mechanical rock cutting process. This study provides a framework to understand and improve drilling performance for HPHT wells, including deep and hot geothermal wells.
Methods for Evaluation of Wellbore Collision Probability in Critical Close-Proximity Regions
Authors: Bang J. , Aklestad D. 
Published: February 2024

Summary
A previous paper (Bang, 2017) has described a general method for calculation of the probability of collision between two wellbores. The present paper focuses on the sections along both wells where the collision probability is significant. Our hypothesis for this study was that for such limited sections of the wellbores, approximations and alternative mathematical approaches might increase the computational efficiency without too large sacrifices of the result's accuracy.
The potential benefits have been investigated through numerical calculations. The results indicate that using a constant uncertainty instead of the actual, varying uncertainty across the entire close-proximity region may increase the computation efficiency. However, we also found that this approximation should be applied with care, because it may generally be difficult to define the constant uncertainty with sufficient accuracy, based on a priori data. Furthermore, we have evaluated the current method of calculating probabilities in metric space against calculating in Mahalanobis space. These two approaches are mathematically equivalent. For our implementation and limited range of testing, the two methods are about equal with respect to computation efficiency.
We have also identified some important topics for future studies. Among these are identification of adequate parameters and efficient algorithms for collision risk analysis at various well proximity ranges, and evaluation of the appropriateness of established model assumptions in light of the industry's current needs and practices.
Practical Challenges to Consider for Model-Based Engineering in Drilling Automation
Authors: Whitlow Zackary W. , Mahjoub Mohamed , Menand Stephane , Pastusek Paul , Payette Greg , Nguyen Khac-Long , Gildin Eduardo 
Published: February 2024

Abstract
Model-based engineering has become more prevalent in the drilling industry over the last few decades. While there is great value in using models, a realistic understanding of the types of problems that can be solved with models, the associated cost, and limitations is critical. Understanding these challenges will help facilitate communication, planning, and collaboration. This paper describes some of the challenges to understanding and ultimately automating drilling processes using models.
Examples of models used to solve industry problems are torque and drag, stick slip, surge and swab, drillstring dynamics, and many more. Models may be data-driven, or physics based, steady state or dynamic, high fidelity or reduced order for execution speed and clarity. To learn from a high-fidelity model, data must be collected and fed to the model and parameters estimated to reproduce the behavior of interest. Often there is not enough data to be certain of the relevant dynamics either because of aliasing or sparse sensor placement. Models for control systems and automation must be controllable and observable which means that most of the high frequency dynamics which represent things like high frequency torsional oscillations and whirl are eliminated, high fidelity is not appropriate. Specifying model requirements and modifying existing models to meet those may require a significant effort which should be considered when planning projects.
The goal is to provide an overview of common use cases for models, and a general description of associated model requirements, to illustrate some of the challenges and costs involved in drilling automation. Processes involved in developing models for specific applications are not described in detail. Instead, the reader is referred to relevant literature.
Drilling Integrity Analysis and Optimal Well Placement Based on 4D Coupled Geomechanical Modelling and Natural Fracture Prediction
Authors: Haas M. , Cifuentes H. R. , Ahumada J. S. , Suarez Y. O. , Gomez J. C. Acosta , Abad F. , Sorgi C. , Hussein A. M. 
Published: February 2024

Abstract
Wellbore instabilities and mud losses lead to costly and time-consuming drilling issues. The identification of these drilling risks is inevitable when it comes to estimating time, costs, and the success of wellbores for exploration and production in reservoirs. The goal of this study is to assess drilling integrity and enhance drilling program designs for forthcoming wells in the reservoir located in the Matachín Field, Colombia based on a high-resolution 4D geomechanical model and incorporated natural fractures. The study involves examining the prediction of natural fractures and stability of wellbores during production scenarios, with the aim of minimizing non-productive time in future wells, irrespective of their trajectories.
An advanced geomechanical workflow was developed in four stages. The first stage involved gathering all data through a screening process. The second stage was data integration, which involved constructing a structural model by incorporating geological attributes and single well profiles, including geomechanical parameters, stress distributions, and pore pressure. In the third stage, present-day stresses were analysed, and their evolution was examined due to changes in pore pressure from the reservoir model and imposed tectonic strains. The fourth stage involved analysing stresses, elastic and rock strength properties for field integrity, drilling integrity, discontinuity stability analysis, and optimal well placement ultimately incorporating natural fractures. Geomechanical properties and stresses were derived from wireline logs at well scale and calibrated against available measurements, such as rock core tests, formation tests, and wellbore deformation analysis. Dynamic pore pressure data up to present-day were included to assess stress changes caused by depletion. The results of 1D geomechanical analysis were upscaled into 3D and incorporated into a complex structural grid along with fault and discrete fracture network models.
The 3D model shows that well trajectories can be improved for increased wellbore stability, resulting in a significant decrease in predicted wellbore collapses. Pore pressure changes that occur due to depletion (production) are explicitly reflected in the reservoir section. As one of the first 3D geomechanical studies in the Colombian Matachín field, the model provides a robust subsurface stress distribution that allows conclusions on safe and optimal well placement. The 3D model serves as the basis for future studies to incorporate new information available from well data and laboratory data. New geological and seismic interpretations allow for an extension of the model area to yet unexplored regions.
Mechanistic Study and Chemical Design of a New Lubricant for High Salinity Drilling Fluids
Authors: Brockhoff J. , Taylor M. , Dubberley S. , Ma K. , Jaska C. 
Published: February 2024

Abstract
The drive to reduce freshwater consumption has led to a significant increase in the use of waste streams, such as high salinity produced water brines, as base fluids in drilling fluid systems. However, the performance of conventional lubricants is typically reduced in such brines. This paper describes the design and development of a new class of lubricant specifically designed for use in high salinity water-based drilling fluids.
A comprehensive literature review and a detailed laboratory testing program were undertaken to investigate the mechanism of drilling fluid lubricants under downhole conditions. The knowledge gained from this study was used to design a new class of lubricant that undergoes a chemical reaction with high salinity brines in order to activate the lubricant species and maximize performance.
A series of field trials were conducted on wells targeting the Montney formation in Western Canada. The drilling fluids consisted of solids-free sodium chloride, calcium chloride, and produced water brines with densities ranging from 1080 – 1330 kg/m3. The wells had lateral lengths ranging from 1580 – 4000 meters. The new lubricant significantly out-performed conventional lubricants on 100% of the field trials and was able to achieve friction factors close to those of oil-based drilling fluids. A series of in-depth case studies are provided which highlight the unique performance characteristics of this novel drilling fluid lubricant.
Enhancing Stuck Pipe Risk Detection in Exploration Wells Using Machine Learning Based Tools: A Gulf of Mexico Case Study
Authors: Gomes D. , Jaritz T. , Robinson T. S. , Revheim O. E. 
Published: February 2024

Abstract
We present a case study on the utilization of a machine learning (ML)-based computational tool for detecting stuck pipe risks early in live operations. The system was used in two Gulf of Mexico (GoM) wildcat exploration wells. The risk detection approach is based on a novel technology using physics-informed machine learning models to analyze real-time data and detect potential stuck pipe incidents in live operations. The ML models were pre-trained on a variety of wells from different fields. The system was designed for out-of-the-box usage, which supports operational monitoring for exploration wells without pre-training on offset well data. The methodology and the process of integrating the computational tool into live operations, and the flow of data between the tool and the drilling operation is described. Additionally, the paper delves into drilling practices that helped to prevent stuck pipe and examine specific incidents that were unavoidable.
The application ran stably throughout the operations, with high uptime and few false warnings in both wells; on average, fewer than one false alert was observed per day of operations. The pre-trained models proved effective, requiring no additional training; this generalizability is an important prerequisite for utility when applied to exploration wells, where offset data may be unavailable. However, due to lack of personnel to follow up the system's outputs in real-time, the benefits were limited. The first well was drilled without stuck pipe incidents. Some sticking risk symptoms were identified during the operation, especially in a fault zone. The post-well analysis indicates that good drilling practices were enough to mitigate the risks. The drilling practices responsible for the success of the operation will be discussed. In the second well, there were stuck pipe incidents. The application provided some indications of stuck symptoms but with some limitations for how far in advance the risk could be detected. The causes of the stuck incidents, the challenges in avoiding them, and updates to the risk detection system for identifying these, will be explored. Based on the experience described in the paper, the authors will offer recommendations for optimal technology utilization both from the application's and organizational perspectives.
Barriers in Cancer Risk Reduction in Community in Indonesia: A Qualitative Study
Authors: Tiranda Yulius , Nuntaboot Khanitta , Septiwi Cahyu , Agianto  , Solikhah Solikhah 
Published: February 2024

Abstract
Background: Posbindu Penyakit Tidak Menular/PTM (Integrated Development Post of Non-Communicable Diseases) is one of the strategies implemented by the MOH of Indonesia for prevention, screening, and early detection through community empowerment and community involvement in reducing the number of NCDs, including cancer. The aim of this study was to explore the barriers in reducing the risk of cancer. Methods: Twelve participants were involved in this study using in-depth interviews and participant observations. All the interviews and discussions were recorded using an audio tape recorder and also using field notes, and then a transcript was transcribed verbatim. Results: Five themes emerged namely providing funding for the program, obtaining appropriate support from the government based on the community’s needs and a health workforce shortage, sharing and discussing the health information, and cultural practices of the community as barriers to reducing the risk of cancer in the community. Conclusions: The study results can be used as evidence to develop and to sustain effective strategies to address the barriers to reducing the risk of cancer in communities in Indonesia.